Hi everyone !!
Ok, if you are interested(and it is, i'm advising to read through it, plenty of good info) i've posted this discussion before on 24/08/07 ''Electric shock from mic while touching guitar, ......''
I just came across the same problem a while ago, last week !!
My mixer was plugged in to a socket in the wall, so as musicians, but spread in different corners, different sockets (all on the walls).
And, to stop the mic from being electically charged, all i had to do was: Plug out my mixer which was going to a socket in the wall, and in the same socket (on the wall) i plugged in an extention lead, and then i plugged in the mixer in the extention+vocalists guitar ?!
Sounds strange to me but it worked !!
Could anyone explain to me (and to all of us) why did it work ?!
I just can't understand it !! Lost !!
Thanks guys !!

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Don't blame the world
Find a solution !!

Assuming the guitar amp was properly earthed, then by plugging the guitar amp into the same mains extension as the mixer, you ensured their earths were at the same potential, and thus no shocks.

I suspect the socket that the guitarist was using originally had no earth, or a very poor earth.

There really is no excuse these days for not checking each and every mains socket used in every venue with a simple socket tester to make sure they are wired correctly and are safe to use.

It is also a much better idea to run everything from the same socket or adjacent sockets, to reduce the risk.

Hugh

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Technical Editor, Sound On Sound

Call me extremely pedantic...

It's very rare that a mic will ever give you an electric shock. It's almost always the fault of the guitar / amp; it's only by touching the earthed mic that this becomes apparent. It always winds me up when people blame the mics rather than the true cause...

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There's nothing we can't face... Except for bunnies

i dont think it has anything to do with the amp.
i played at the colston hall in bristol and i even had problems there, and my equipment is certainly earthed!
It was that our amps were plugged in to a different circuit to the mixing desk

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Live Sound and Studio Engineer

Quote Paul Supersonix Studios:

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i dont think it has anything to do with the amp.

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To be fair, it is most usually a problem associated with a disconnected earth on guitar amps (to kill the hum, man!).

Quote:

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my equipment is certainly earthed!

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I'm glad to hear it, but can you be as certain that the socket you plugged it into is properly earthed, or that the equipment, sockets, mains cables and plugboards that everyone else uses are properly earthed?

The only way to be sure and safe is to test the mains sockets you plan to use before using them, and check that everyone's equipment is earthed correctly before allowing them to plug anything in.

Quote:

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It was that our amps were plugged in to a different circuit to the mixing desk

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Then there was a potentially lethal fault somewhere in that building. The difference in earth potential between sockets should be no more than a volt or two at most. To feel a shock when touching an earthed mic suggests that an earth was missing from the singing guitarist's rig. If that's the case, then he is playing on borrowed time....

Hugh

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Technical Editor, Sound On Sound

yeah well as hundreds of professional touring chart topping artists play there every year you would have thought that it would be properly earthed? maybe not,
the reason i said it wasn't the guitar amp was because i was getting shocks(and i play bass and sing) and so was our guitarist(who also sings) and its never happened before?

Edited by Paul Supersonix Studios (06/02/08 12:59 PM)

Quote Paul Supersonix Studios:

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yeah well as hundreds of professional touring chart topping artists play there every year you would have thought that it would be properly earthed? maybe not,

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The first rule of not dying is to not make assumptions like that. Faults happen. Things can change. When we rigged for some SOS seminars at the old Wembley Arena site, I found four faulty sockets in the same conference room -- a room that was used everyday by all and sundry. One socket had no earth, two were live-neutral reversed, and one just had no power. It happens! Often, the screws clamping the cables inside work lose or tarniosh and oxidise. Sometimes they weren't done up tight in the firtst place, and as the cable oxidises the connection goes high-resistance. That's all that's needed to make the safety earth next to useless! Sometimes someone else has had a major fault and the cable or the socket has been damaged but not reported to be fixed. Hence my advice to check them before using them.

Quote:

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the reason i said it wasn't the guitar amp was because i was getting shocks(and i play bass and sing) and so was our guitarist(who also sings) and its never happened before?

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Were both your amps plugged into the same mains extension plug board by any chance? Or the same wall socket? If so, you've probably just identified where the missing earth was.

Clearly, there was a serious and potentially fatal fault somewhere. It could have been the earths protecting the sound desk, or it could have been the earths protecting the guitar and bass amps.

In my experience, shocks when touching a microphone are almost always because the mic body is properly earthed but the guitar amp's earth is disconnected, so that the 'earthed' metalwork on the amp (and guitar string earthing) floats up to half mains voltage (115V).

You won't feel that while playing as long as you don't touch anything else earthed, but the moment you do, you'll get the shock.

Now the missing earth might not be because the safety earths in the amps have been deliberately disconnected -- it could just as easily be because a mains cable or extension board has been damaged, or the wall socket could be faulty, as I've explaiend.

It's a less common scenario, but certainly still one worth investigating, that it could equally have been the other way around -- the guitar amps were properly earthed and it as the mixing console earth that was at fault. In that case, the mic's body would have floated to 115V, but you would have got the same tingle effect through the grounded strings.

Sadly, without all the same equipment set up in the same room in the same way, we'll only ever be guessing what the actual problem was. But it would be foolish to dismiss it and not check everything you can carefully.

As I said, the location of that discontinuous earth (or earths -- there could be more than one fault here) could be at any of a variety of places. The wall sockets, the extension cables, the mains plugs, the mains cables, the pluig-boards, or inside the equipment itself. The only way to be sure is to check every single mains cable you used, every extension cable, and every piece of equipment.

In fact, this really is something you should do regularly anyway. Cables get snagged and cut, or tripped over pulling the wires from the plugs, and screw connections inside plugs can work loose and wires corrode and oxidise.

If they all check out okay, then it was probably the mains sockets in the venue -- it really isn't that uncommon! Buy a tester, and make a point of using it next time. it only take a few seconds. Also, to be almost completely safe, make sure you run all your own equipment through an RCD, and persaude all the others in the band (and FOH) to use RCDs too.

Hugh

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Technical Editor, Sound On Sound

ok thanks hugh that makes a bit more sense now, it was a while ago so cant exactly remember where we were plugged in to but yeah i always use RCD's now.

it only happened when we sang and touched our strings.
Cheers

Edited by Paul Supersonix Studios (06/02/08 02:15 PM)

Quote Paul Supersonix Studios:

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it only happened when we sang and touched our strings.

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Yes, it would.

Normally, the strings are earthed through the guitar cable's screen to the guitar amp, and from their to the mains safety earth of the amp's mains lead.

The mic body is earthed through the mic cable screen to the mixer, and from there to the mains safety earth of the mixer's mains lead.

If one or other of those mains safety earths becomes high resistance or disconnected, then the mains input filtering of the amp or mixer will tend to pull everything connected to the now disconnected earth line up to half mains volts (115V in the UK and Europe).

If you are playing the guitar while touching the mic body as you sing, you complete a circuit, one side of which is earthed, and the other is sitting at 115V. it doesn't matter which way around it is -- which side is still earthed and which is floating -- the results ae the same.

If you're lucky it will just tingle unpleasantly. If you're unlucky there'll be a bang and the gig will come to a premature end... as will the person who formed the link in the circuit.

You said this only affected you and the guitarist, and that's often the case. Vocalists generally only touch the mic and nothing else -- so there is no circuit. Likewise keyboard players generally only touch plastic keys, so there's still no circuit.

The worst case scenario is when the circuit is formed across the hands -- one hand on the guitar strings, the other on the mic. That way any current flow is straight across the chest, through the heart, and is likely to stop the heart. One ex guitarist...

Hugh

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Technical Editor, Sound On Sound

never happened to me b 4 but thanx 4 posting that thread...
it's gonna save me loads of time in the future...cause i'm sure it'll happen

Quote Paul Supersonix Studios:

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i played at the colston hall in bristol and i even had problems there, and my equipment is certainly earthed!
It was that our amps were plugged in to a different circuit to the mixing desk

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I could tell you a few stories about that venue, but probably had better not.

Most touring acts will plug distro into the heavy stage power tie stage right (good for 400A or so IIRC) and forgo the use of the random 13A points except for back stage tea and coffee.

That the earthing is a little suspect comes as no surprise (No reflection on the house crew, council run venue and Bristol council, well 'nuff said).

I would heavily advocate always testing before you plug in anywhere, in any venue and that the use of RCD protection on backline supplies is just good sense (along with FOH if you don't trust things).

Note that most simple socket testers cannot identify a neutral/earth reverse.

There are a scary number of dodgy sockets out there, test everything and be paranoid, it's good for you.

Incidentally, IME CEE form sockets are less likely to be miswired as people pay more attention to the 'industrial' power then they do to the domestic stuff (Good reason to use them if available).

Regards, Dan.

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Audiophiles use phono leads because they are unbalanced people!

the engineer was a right pr*ck he just said "deal with it". in the end our guitarist just got so annoyed at the end of the set just smashed over the mic stand lol

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Live Sound and Studio Engineer

Hehe my guitarist was getting static off his guitar in band practice dont know why it happend, he was also using a mic at the time and quite close to the amp and socket. It was amusing to watch when now and again hed jump in the middle of a song with a small yelp!

haha yeah its not fun if your being shocked after a 30 minute set my mouth was burning.

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Live Sound and Studio Engineer

Quote Paul Supersonix Studios:

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the engineer was a right pr*ck he just said "deal with it". in the end our guitarist just got so annoyed at the end of the set just smashed over the mic stand lol

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You are completely within your right to walk out there.

NOTHING is worth the risk you just put yourself through(30 minutes???!!!!). If they have a problem with you walking out, tell them you will feel happy to have the local inspector come in and make sure the building is up to code and if that is the case you will come back. But until then something is very much NOT right there and they are endangering lives like that. Honestly the engineer that says, deal with it, to something like that needs to be fired on the spot. Maybe then he will learn not to screw with electrocuting people.

Seablade

NOTE: I am in the US, though I would imagine a similar safety inspection exists in the EU for such situations.

City council venue Seablade, the place (a ~1,800 seat somewhat run down neoclassical pile last time I was there) is owned by the AHJ! I understand that they have done some work on it in the interim, but the real plan for as long as I can remember has been to replace it.

This is the council which owns another venue where you always had to ensure a lantern was plugged into the first socket on the FOH bar and securely clamped to the bar as that was the only one with the earth connected (Lots of moaning from us, zero action from the council, and this is in 240/415V land)! Mind you, they also supplied me a 'street lighting technician' to fill a rider requiring the venue to provide a 'lighting technician', nice guy, but about as useful as a chocolate fireguard.

I do wonder if that 'engineer' was actually a hired in PA company as I don't recall that place having any PA worthy of the name (And from what I recall of working there a few times, that does not sound like behaviour the resident chief would have accepted from his people).

It does however sound like the sort of thing a pissed off third party sound provider might perpetrate after a bad day.

Regards, Dan.

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Audiophiles use phono leads because they are unbalanced people!

Quote DingoDave:

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Hehe my guitarist was getting static off his guitar in band practice dont know why it happend

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Not being funny here, mate, but you are dismissing a seriously life-threatening situation here. You need to find out why it happened. Something is UNSAFE in your rig.

Quote:

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It was amusing to watch when now and again hed jump in the middle of a song with a small yelp!

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I wonder how many people will laugh when your mate -- OR YOU -- DIE!

This is serious and it happens everyday. And if something nasty does happen, and it can be shown that you were aware of the fault but did nothing to rectify the problem, it won't do you much good either!

Seriously -- sort this out NOW. Get the gear checked. Get the room wiring checked.

Hugh

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Technical Editor, Sound On Sound

I know it's been said a million times before, but surely we can all agree that this topic warrants being made a sticky.

Also, Dan/Hugh/anyone, do you have a particular socket tester that you recommend? I know for a fact that my rather basic Maplins jobby (the name of which completely escapes me) will spot a disconnected earth, but won't pick up on a reversed live/neutral. Dan, I think I've heard you talk about stuff Martindale(?) before now?

Quote dmills:

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City council venue Seablade, the place (a ~1,800 seat somewhat run down neoclassical pile last time I was there) is owned by the AHJ! I understand that they have done some work on it in the interim, but the real plan for as long as I can remember has been to replace it.

This is the council which owns another venue where you always had to ensure a lantern was plugged into the first socket on the FOH bar and securely clamped to the bar as that was the only one with the earth connected (Lots of moaning from us, zero action from the council, and this is in 240/415V land)! Mind you, they also supplied me a 'street lighting technician' to fill a rider requiring the venue to provide a 'lighting technician', nice guy, but about as useful as a chocolate fireguard.

I do wonder if that 'engineer' was actually a hired in PA company as I don't recall that place having any PA worthy of the name (And from what I recall of working there a few times, that does not sound like behaviour the resident chief would have accepted from his people).

It does however sound like the sort of thing a pissed off third party sound provider might perpetrate after a bad day.

Regards, Dan.

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Again, yank over here sadly, but I would say then the next step is to take it over the city. At least in the US this would violate NATIONAL safety standards, so there is nothing stopping someone above the city from shutting it down if need be. Again I would venture a guess in the EU that a similar situation exists.

I know it sucks, but honestly they need to be forced to do something. This is waiting for someone to die as described right now. No hyperbole at all, it literally is a matter of waiting till the first person dies before anything is done unless someone goes over their heads if the city is unwilling to do anything with it.

Honestly, there have been venues I have told production companies never to book again as they were dangerous along this level. This would certainly qualify, step one is to never play it again, and make sure noone you know plays it until they get this fixed. Step 2 would be to report it over the heads of the city IMO.

Seablade

Quote Matt P:

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I know it's been said a million times before, but surely we can all agree that this topic warrants being made a sticky.

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Yea at this rate, I gotta agree, something needs to be done to keep this perfectly visible, not sure if a sticky thread is the right answer or not. Maybe an FAQ section along the lines of Martin's computer FAQs? Ah well up for the mods/admins to decide not me.

Anyways to answer your other question I bought this kit for basic electrical analysis that I carry with me.

http://www.lowes.com/lowes/lkn?action=productDetail&productId=205783-7 2068-TK-30&lpage=none

I believe the socket tester in it wil check for a live/neutral reverse, but I will double check tomorrow. At the moment I need to get some sleep and don't feel like getting dressed to go out to the car to check.

Seablade

when i have this problem i use a multimeter and the odd radiator to find which earth is bad and then i put a sticker on it saying "Faulty. This is not to be used until repaired" then i tell the venue management what i've done and suggest that it's repaired. If i'm feeling really bolshy i'll follow it up and report them to the local coucil, their licensing authority or HSE if the sticker was removed without being rectified (i have done this to a council venue whose 63Amp supply was LN reversed).

if you knew what you were doing and if you had the appropriate test gear, you could measure between the earth connections on the stage and mixer supply sockets and see if there is a voltage -more than 5 volts or so suggests a possible problem, double figures means a definite issue with earthing in the building. i have found over a 120 volts on an earth in a leisure complex venue.

a missing or dodgy earth is potentially lethal should a fault condition occur, and the venue would be fined heavily or shut down once HSE had been in there should there be an accident (happened to a franchise of a food chain in my home town after a lethal shock).

also any venue needs an annual electrical inpection to get their PEL, so it would be good to ask for a copy of the report for this "council-run" venue -i think as a council they are obliged to supply one to a formal request. stir up some mud, you might get things to happen before someone dies.

that aside, the usual reason for shocks on microphones is a removed earth on guitar amp plugs -in this case it could be a bad earth from either side from the mains sockets.

anybody who lives in Bristol fancy verifying this? it does sound like something does need to be done.

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planet nine
lincoln, uk.

Thanks to previous SoS threads on this, I now always bring my 'Martindale socket tester' to everygig,
and fit a couple of Wickes RCDs onto the bands' gear.

Occasionally they trip out in the middle of songs, so the band can be a little "auch! not that bloody thing that ruins our gigs!" but I just keep reminding them that leaving the stage in an ambulance would ruin the gig even more.

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~~~ A weasel hath not such a deal of spleen as you are tossed with! www.feline1.co.uk ~~~

find an electrician friend to measure your gears leakage current feline -most PAT testing gear will do this -see if you have some borderline equipment or if you have any congealed beer in any of your socket strips...

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planet nine
lincoln, uk.

Quote:

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I do wonder if that 'engineer' was actually a hired in PA company as I don't recall that place having any PA worthy of the name (And from what I recall of working there a few times, that does not sound like behaviour the resident chief would have accepted from his people).

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nah it was the inhouse lampy i think. they have some sort of turbosound rig in there, not very good though.

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Live Sound and Studio Engineer

Quote Nathan:

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find an electrician friend to measure your gears leakage current feline -most PAT testing gear will do this -see if you have some borderline equipment or if you have any congealed beer in any of your socket strips...

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nah, the time it tripped, there was spilt beer about an inch deep all over the stage and the 4-ways, so "go figure", etc etc...

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~~~ A weasel hath not such a deal of spleen as you are tossed with! www.feline1.co.uk ~~~

heh, no argument

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planet nine
lincoln, uk.

Quote Nathan:

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also any venue needs an annual electrical inpection to get their PEL, so it would be good to ask for a copy of the report for this "council-run" venue -i think as a council they are obliged to supply one to a formal request

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Yep - with very few exceptions, under Freedom of Information they are required to supply any document held by the public authority.

The request for information must be somehow written down (email considered fine) but technically doesn't have to be in any way "formal".

You don't have to live in bristol - anyone should be able to email: foi at bristol.gov.uk and ask for a copy of the report....

As this is a topic that comes up regularly, and is 'mission critical' I have made it a sticky as suggested.

hugh

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Technical Editor, Sound On Sound

Quote Hugh Robjohns:

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As this is a topic that omes up regularly, and is 'mission critical' I have made it a sticky as suggested.

hugh

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Applause!
Righto, is there prize for writing the best definitive Electrical Safety guide?

Hi all,
At the weekend I was getting small shocks from the main vocal mic (our singer doesn't play any instruments or have anything plugged into mains). There was no unecessary phantom power and the problem was only on the main vocal. I was splitting it into 2 channels and using 1 to drive monitors... could it have been something in the desk? Anyone got any ideas how this can be fixed if i encounter it again?
Cheers
Pete

Tried to search in this thread about it, but i was surprised to see that noone came with the suggestion to put a DI between the amp and the guitar to prevent shocks.
Of course you have to plug the DI into the mixer or remotebox on the stage, just to even out the differences in current between different outlets. But with that done, you won't have any problem with shocks while grabbing your guitar and singing.

Best regards
Sylvester

That won't fix any problems with earthing on the mains sockets, though...

You could still injure/kill yourself.

Although, on the bright side, that annoying hum will have been stopped...

Dodgy socket wiring would be my bet for the shocks from the (non guitarist) vocal mic.
Get a simple three lamp socket tester, and use it every time, you will find some amazing things.

On the subject of guitars, I have one that has had a low value class Y cap added in series with the lead that connects the bridge to the screen.
It has little effect on the screening, but means that the path to the amp will be too high impedance to deliver a belt that is likely to be fatal (Cheap insurance, and I commend this modification to the house).

Not of course that this makes lifting the safety ground safe, but it does provide some protection against muppetry.

Regards, Dan.

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Audiophiles use phono leads because they are unbalanced people!

Quote dmills:

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Not of course that this makes lifting the safety ground safe, but it does provide some protection against muppetry.

Regards, Dan.

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LOL.
Good one.
Should be in 'Top Tips'.

Cheers Dan,
I'm not totally sure what you mean by the socket tester.. the only power she could have been connected to was from FOH.. on it's own feed from the distro... maybe test that output? I don't get how we didn't encounter the same problem with other (vocal) mics.
Cheers
Pete

Quote PeteJ:

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At the weekend I was getting small shocks from the main vocal mic (our singer doesn't play any instruments or have anything plugged into mains).

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By small shocks, do you mean static 'zaps' -- short, sharp zaps that are not continuous -- or do you mean half mains voltage continuous electric shocks?

The former is caused by clothing or flooring, generally and isn't lethal but can be startling. The latter is potentially lethal...

I'm ubnclear when you say you got shocks but the singer doesn't play anything. Was the singer getting shocks too?

Quote:

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There was no unecessary phantom power

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Phantom power is DC and low voltage, so it's not a factor in this.

Quote:

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and the problem was only on the main vocal.

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That is very odd... and quite unlikely if it is real faulty-earth style electric shocks! But could be possible if it was static shocks.

Quote:

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I was splitting it into 2 channels and using 1 to drive monitors... could it have been something in the desk?

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Do you mean two channels of the same desk, or split to two different desks?

Quote:

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Anyone got any ideas how this can be fixed if i encounter it again?

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Check all the mains earths on all the equipment, mains leads, and distro boards. Check the wall sockets at the venue before using them. And power eveything via RCDs.

hugh


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Technical Editor, Sound On Sound

Thanks Hugh...
Static shocks I reckon. Sorry about the confusing bits.. I just mix the band so when I said myself and the singer it was me during soundcheck and her during the show. Maybe it was floor / clothing related.. I'll check out what she's wearing next time. Any other ways of minimizing this? Changing cables / stands / mics?
The channel thing was just that I had to mix mons + foh from the same board so I y-split the main vocal into 2 channels of the same desk - then used one for out-front and one to send to monitors with different eq.
Thanks for your help..
best
Pete

Quote PeteJ:

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Static shocks I reckon.

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Yes, sounds more likely.

Quote:

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I'll check out what she's wearing next time. Any other ways of minimizing this?

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Can't do anything with the mics/stands etc. They have to be earthed for safety. Best to check your lady singer for static-inducing underwear before every gig

hugh

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Technical Editor, Sound On Sound

Quote Hugh Robjohns:

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Best to check your lady singer for static-inducing underwear before every gig

hugh

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You could always attach some of those static tails you used to see under the rear bumpers of cars in the 80's.

Quote:

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Best to check your lady singer for static-inducing underwear before every gig

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Something I've made a point of for years. Sometimes a visual check alone is not enough, as you're doubtless well aware. However, no matter how the check is carried out, I find the best option is to ensure it's removed, and held in safe keeping pending further investigation.

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[url=http://www.facebook.com/pages/hifi-studios/117322741632389[/url]

The HS executive do a leaflet on electrical safety for entertainers. You can download it here as PDF file:

HSE executive PDF on electrical safety for entertainers

Note sure it adds much to the discussion, but it's a useful reminder.

Thanks all
Turns out she had three layers of nylon on under that dress!... hang on... make that four

valentine's day is coming... buy her some silk!

Hugh

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Technical Editor, Sound On Sound

Off Topic, Off Topic ...pheeeeep!



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planet nine
lincoln, uk.

Yerst... it all needs takihng off...

one layer at a time...

slowly...


video please!!!!

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[url=http://www.facebook.com/pages/hifi-studios/117322741632389[/url]

Quote Grim Audière:

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The HS executive do a leaflet on electrical safety for entertainers. You can download it here as PDF file:

HSE executive PDF on electrical safety for entertainers

Note sure it adds much to the discussion, but it's a useful reminder.

---

Good man.
Definately ON topic!

Quote seablade:

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Quote Matt P:

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I know it's been said a million times before, but surely we can all agree that this topic warrants being made a sticky.

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Yea at this rate, I gotta agree, something needs to be done to keep this perfectly visible, not sure if a sticky thread is the right answer or not. Maybe an FAQ section along the lines of Martin's computer FAQs? Ah well up for the mods/admins to decide not me.

Anyways to answer your other question I bought this kit for basic electrical analysis that I carry with me.

http://www.lowes.com/lowes/lkn?action=productDetail&productId=205783-7 2068-TK-30&lpage=none

I believe the socket tester in it wil check for a live/neutral reverse, but I will double check tomorrow. At the moment I need to get some sleep and don't feel like getting dressed to go out to the car to check.

Seablade

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For the record, yes mine does do a Hot/Neutral Reverse check. Cheap 20 buck kit got me a cheap multimeter, a socket tester, and voltage detector, not a bad deal to me.

Seablade

Good link here;

http://professional-sound.com/soundadvice/datadirectory/viewnews.cgi?id=11 91436814

I really do love my wireless setup as it puts several feet of air between me and electrocution

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Crazy guitar beating - www.myspace.com/dalecampbell

There is something to be said for that...

Hugh

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Technical Editor, Sound On Sound

For the new BS7909 code of practice (in draft now) it is recommended that (for small systems from 13A outlets etc) you check the sockets using at least a socket test device that includes an Earth loop indicator and you should not use any socket that has an earth loop above 500 ohms, something like this http://www.martindale-electric.co.uk/sockets.htm#ez150

You should also have an RCD, and you may need to bring this with you as some places still do not have them fitted.
see also the HSE publications: INDG247 - Electrical safety for entertainers http://www.hse.gov.uk/pubns/indg247.pdf
and GS50 Electrical safety at places of entertainment which is is for the venue.

Now (referring to a post up the page a bit, where Hugh seemed to be suggesting that mics and stands are earthed for safety reasons) that would be a first for me - did you really mean that mic. stands should/must be earthed? I don't think I've ever seen that. Mics, yes. But stands? How would you do that?

Edited by revbobuk (01/04/08 05:24 PM)

Quote revbobuk:

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Hugh seemed to be suggesting that mics and stands are earthed for safety reasons) that would be a first for me - did you really mean that mic. stands should/must be earthed? I don't think I've ever seen that. Mics, yes. But stands? How would you do that?

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I didn't mean to suggest that stands should or must be earthed. The metal body of mics are through the cable screen, obviosuly. Stands can become earthed because of contact with other earthed metalwork.

Performers usually get shocked becasue they are holding the guitars strings in one hand (which might be floating at half mains voltage or worse of the amp is missing it's protective earth), and then touch the mic (the body of which is earthed through the mic cable and mixer).

hugh

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Technical Editor, Sound On Sound

The venue must test socket outlets as a licence requirement in most cases. This is done formaly be electrical contractors or competent in house electrictians.

If sockets are not safe don't use them, walk away and if anyone hassels you remind them that electrical systems have to be safe as a requirement of the Electricity at work regulations 1989 under the HASAW act.

The IEE wiring regulations BS7671:2008 which now include temorary stuff for shows refer you to BS7909, which is being updated and is available in the 1998 form or as a draft 2008 version.

Both BS7671:2008 and the draft of BS7909:2008 recomend that the socket outlets are tested before use, for saftey particularly to check that the protective earth is continuious and that the resistence to ground is low enough to be effective in enableing the effective operating of protective devices.

I would as a minimum invest in a decent socket check plug with an indication of earth fault loop impedence.

More information about these things can be found at these links:

www.hse.gov.uk/electricity/socket1.htm
www.hse.gov.uk/pubns/indg247.pdf

http://www.martindale-electric.co.uk/sockets.htm#ez150

I am going to try to get permission to use section 5 of the proposed BS7909:2008 available as part of a free or low cost information sheet for lay electrical users.

well from my personal exprience,as a singer/guitar player
i found when getting a shock from a mic,usually come from a bad ground,due to plugs being in different wall sockets
and man it can hurt sometimes,my easy fix is,put my guitar
mixer and power amp all on the same wall socket,problem fixed
but this is really isn't a long term fix

there is bigger problem with the electrical in the house or building,some people call it dirty power,and could result
in a fire cause by an electrical problem,meaning the place could burn to the ground and you lose everything
and it might be good to have an electrical inspector
come in and check everything out

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Just a Musician

Did the venue have three phase power and if so was ALL the audio equipment plugged into the correct (ie. same ) phase?

Quote Roidster:

---

well from my personal exprience,as a singer/guitar player
i found when getting a shock from a mic,usually come from a bad ground,due to plugs being in different wall sockets
and man it can hurt sometimes,my easy fix is,put my guitar
mixer and power amp all on the same wall socket,problem fixed
but this is really isn't a long term fix

---

It is important to note, that if that socket has a faulty ground, this will not fix the real problem. Good grunds are important.

Quote:

---

there is bigger problem with the electrical in the house or building,some people call it dirty power,and could result
in a fire cause by an electrical problem,meaning the place could burn to the ground and you lose everything
and it might be good to have an electrical inspector
come in and check everything out

---

What most people call "Dirty power" is actually a bit different. It ranges in definition, but in general it tends to fall into the category of under or over-voltage power coming from a bad source, or overly taxed distribution. I have also seen it refer to poorly isolated power, leading to similar problems as above, for instance an elevator motor starting up causing the sound system to get an under-voltage as it draws power.

Seablade

Many thanks for the info and links. This is something that's been on my mind recently, ever since I got a nasty shock from a standard lamp of all things - although I am very gratefull that it wasn't anything more than nasty, and that it was me not one of my customers. It was a lamp we move round quite often, and poor design meant that every time it got moved it rubbed a little more insulation off the live cable... (I know that's meandering a bit off topic but bear with me)

I run a small independent venue and regularly have the electrics checked out. However this incident has brought it home to me that something could go wrong 5 seconds after the electrician walks out of the door, and he may not be back for 6 months to check it out again.

This line was an eye opener for me:

Stewart Newlands Quote:

---

If your socket tester cannot display the Earth Fault Loop Impedance, it should not be used to check whether a socket is adequately earthed and safe to use.

---

I guess I'll have to upgrade to a more expensive tester - the cost is easily justified as you can't put a price on peoples lives.

Sadly, in my experience, this line isn't right:

Quote Stewart Newlands:

---

The venue must test socket outlets as a licence requirement in most cases. This is done formaly be electrical contractors or competent in house electrictians.

---

Unfortunatley I've never seen or heard of this being an actual licence requirement. For example, my own licence has several conditions pertaining to safety such as all fire routes must be kept clear and spills must be mopped up imediately, but naff all about electrics. There is a legal obligation that eveything must be safe, but too many operators look at their licence as being the be all and end all of their obligations. Also, since the changeover to the new licencing laws, I've had 2 "taskforce" visits, which basically means that police, licensing, environmental health and fire officers all turn up together to make sure you're within the letter of the law, but they've never even looked at the electrics! And I know that's the case in various friends venues as well.

Quote Stewart Newlands:

---

If sockets are not safe don't use them, walk away and if anyone hassels you remind them that electrical systems have to be safe as a requirement of the Electricity at work regulations 1989 under the HASAW act.

---

To be honest I'd recommend going one further than that and notifying the EHO (Environmental Health Officer) of the situation. There are a small minority of operators who don't give a damn, but if something goes wrong we all get tarred with the same brush.

Remember, YOU may have the chutzpah to walk away and cancel your gig, but there will be a lot of up'n'coming bands who will happily take that risk for a bit of exposure. That said, please speak to the management first, it could be a new problem and most of us are decent folk who really don't want to see a performer get electrocuted on stage!

Rant over!

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One is too many, two is about right, but three can never, ever, be enough

You can find more information about Electrical Saftey at www.7909.org.uk which will be listing all sorts of stuff regarding BS7909:2008 and BS7671:2008 and entertainment.

There may be some NVQs in this area at some point starting with a level 2, but it is some way off just now.

Quote Mattmvb:

---

Many thanks for the info and links. This is something that's been on my mind recently, ever since I got a nasty shock from a standard lamp of all things - although I am very gratefull that it wasn't anything more than nasty, and that it was me not one of my customers. It was a lamp we move round quite often, and poor design meant that every time it got moved it rubbed a little more insulation off the live cable... (I know that's meandering a bit off topic but bear with me)

---

this guy i knew,was living in a house,but it wasn't the lamp he was getting shocks from
everytime he used any light switch in the house,he would get a nasty shock
it had gotten to a point were he would use a stick to turn on and off the lights,in his house
finally they had gotten an electrical inspector in
he shut the hydro off at the pole and told them
every electical wire that ran through out the walls
floor and ceiling had to be replaced,before they would hook
the power back up
he said to them they were lucky there was never a electrical fire
this was an older house with original wiring,so over time the wires had deteriorated

--------------------
Just a Musician

If your under pressure to get your sound-check done you can try sticking a D.I. box between your guitar and the amp and plug the XLR cable from the D.I. into a stage box. This should solve the problem on the night and the show can go on.

Quote jbk:

---

If your under pressure to get your sound-check done you can try sticking a D.I. box between your guitar and the amp and plug the XLR cable from the D.I. into a stage box.

---

Um. Not convinced about that. The pass through output that goes from the DI to the amp doesn't usually offer any isolation so it won't electrically separate the guitar and (potentially dodgy) amp. Also, most guitar amps are mic'ed which doesn't present any electrical problems so I can't see why you'd want a DI feed instead...
Personally, if there's dangerous electrics on stage, the gig can wait until it's sorted. The show doesn't have to go on if it means putting lives at risk.

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There's nothing we can't face... Except for bunnies

This is if your getting shocks from the mic because the guitar is not properly grounded. you ground it with the XLR into the stage box. It's not a channel your going to use , so it's got nothing to do with the guitar being miced. It works, and always has done. It's not a permanent and far from ideal solution but as I pointed out the show must go on!

Quote jbk:

---

...as I pointed out the show must go on!

---

It takes me about 5 minutes to wire a new edison onto a plug over here. The show must go on, but not at a dangerous cost.

I will admit to being a bit sleep deprived, but at first glance your solution may work, by providing a path to ground with a lower potential, but it is addressing the symptom instead of the problem. Add this onto the fact that removing the shield in an audio cable is not an uncommon occurance to prevent ground loops in a safer way, and you are left with no path to ground except through the performer.

Fix the problem, not the symptom. Especially when it takes a couple of minutes at most, and ensures someone's safety.

Seablade

Wigi brought the matter up but can I reinforce his statement regarding phases please?

It might be very tempting if you run out of outlets to just run another extension to another room. There is NO guarantee that the room is on the same phase and thus the voltage stress on the equipment is greatly increased. Futhermore the earth path resistance will almost certainly be increased.

In older building that have been "knocked about" it is even possible that a socket at one end of the room has been "pinched" thru' a wall from another phase. AFAIK there is no easy, safe, cheap way to test for this so as Hugh says, run eveything from one outlet or those as close together as possible. You can pull nearly six kW from a 13A double, enough for any SOUND system surely!

Dave.

--------------------
#They did not listen, they are not listening still...Perhaps they never will?#

Quote ef37a:

---

You can pull nearly six kW from a 13A double, enough for any SOUND system surely!

---

No you can't! You're likely to start a fire if you try. With most twin outlets, the most you can draw is around 20A; they're not designed to be able to supply 13A from both outlets simultaneously. There are some designs out there that can do so safely but these are the exception rather than the rule.

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There's nothing we can't face... Except for bunnies

Thank you Sheriton. I was basing my figures on a ring I have just put in using 32A trips.

Are you saying the OUTLETS will burn, because the cable can surely stand 32A?

Dave.

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#They did not listen, they are not listening still...Perhaps they never will?#

The sockets themselves can overheat as they're not designed to be able to supply that much current. I believe it's the point where the cables are connected at the back that is the weakest link.

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There's nothing we can't face... Except for bunnies

Well, I was not suggesting a pair of 3kW heaters!

Shall we meet at a 5kW but not a continous load? 20A is not 5k I admit at 230V but we always get 240+ here and that is pretty close.

Our new premises run 250 most of the time and has hit 254 now and again!

Dave.

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#They did not listen, they are not listening still...Perhaps they never will?#

On the phase thing, I would note that running systems across multiple phases is actually NOT a problem (And is done routinely on largish gigs (32A TP+N is a much smaller and lighter cable then 63A SP)), there is 400 odd volts phase to phase sure, but as a minimum of 4 faults are required to end up with two bits of exposed metalwork being live to different phases (Two earth faults and two phase->case faults) this should be a completely negligible risk if your electrical maintenance regime is even halfways competent.

The large earth loop that can result from plugging into multiple locations can cause circulating currents in the screen connections, but as long as nothing has a pin one problem, and everything is balanced, that rarely causes hum (And if it does, just fix the gear already).

One thing to watch with ring mains is that you never know what else is connected to them (Think Ice makers!), but for a general bar gig I would probably be quite happy to run a PA off one, sound requires remarkably little RMS current (and it is that, not smallish short term peaks that causes problems). Lighting is of course another matter.

I would second the advice to get a good socket tester, and getting the local theatre sparks to PAT your gear for you occasionally is never a bad thing (Normally costs a few pints). Hell just opening up the plugs and tightening all the screws once a year goes a long way.

Regards, Dan.

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Audiophiles use phono leads because they are unbalanced people!

Ok Dan,

I take you point about phases. I based my warning on an experience at a factory where I was a general handyman. The power on one wall in the refrectory failed one hot afternoon and there were 3 snack chillers in there. I quickly ran in a couple of mains leads from the testroom outlets about 15mtr away the other side of a breezeblock wall.

I was roundly castigated the next day by the visiting sparks re phase dangers. I did think at the time that you would have to be bloody unlucky.....

Dave.

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#They did not listen, they are not listening still...Perhaps they never will?#

A long time ago there was a requirement in the 'wiring regulations' (BS 7671) to separate all sockets on different phases by 2M, but that was removed many years ago.

There are however still many site electricians that seem to be wedded to following this practise to the point of insisting on it.

I just had some 200 channels of lighting dimmer installed at work we did try to keep it to one phase per bar (not always successfully) on the grounds that it doesn't hurt and there is an outside chance that it may help some day, but it is not something to get overly worried about.

I do however try to keep all the backline on one phase as in my experience this tends to be where the really dodgy stuff turns up (And the venue often does not have easily applied control over it).

FWIW My amp racks (and fixed signal processing) are fed from a three phase supply locally broken down to give the required single phase feeds, are installed right next to the main dimmer racks (the location was convenient), and the whole thing is totally silent.

An awful lot of the time you get moans from sound types about buzz from dimmers it is more a reflection on the sound companies engineering then it is venue or lighting companies...

Regards, Dan.

--------------------
Audiophiles use phono leads because they are unbalanced people!

Just to breathe life into this sticky again, we nearly lost 3 more to electric shock at the weekend.

Kim Rew, Lee Cave Berry & Ted Koehurst were playing a gig with a dodgy 3 phase installation & lost all 3 amplifiers, plus Ted got well and truly zapped.
No dead bodies, but how close do you need to get?
The worrying thing is that the amps worked for one set before frying (and predictably in at least one case shorting to the input jack, which was earthed to the chassis)
Ths was not a bad earth, this was incorrect voltage (440)which makes it even scarier.
I don`t have all the details yet but will try to post once I get in touch with one of them.

RDF`s don`t always get everything folks - especially if you are playing outdoor events/festivals, it pays to carry a good mains tester as well as your own individual RDF device.
Cheap life insurance.

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Me? But I`m such a loveable old bugger!

Hi, I've just been reading through this thread and despite not understnading anything, it worries me.

I've had a few gigs where I have been getting painful shocks off the mic when I touch it to sing (I play guitar and sing).

I don't know anything about electronics so would anyone be able to explain to me (in simpler terms) what I would have to do/buy to ensure that both me and my bandmates are safe both at gigs and at practice?

Thanks very much
Adam

The first thing I'd suggest is to get someone electrically competent to have a look at your guitar amp. The main cause of experiencing a potential difference between your mouth and the mic is that the earth in the guitar amp isn't doing its job which causes the guitar strings to float up to 110v. You won't notice this until you touch something earthed like a microphone.
1st thing to check is inside the mains plug - make sure the earth wire is well & truly connected to the earth pin.

--------------------
There's nothing we can't face... Except for bunnies

a socket tester is also a useful tool,
check every socket you plug your gear into to make sure its wired properly and is earthed

--------------------
Live Sound and Studio Engineer

on the second night of our most recent tour, the singer/guitarist got a nasty zap off her mic during soundcheck.

turned out it was the 4-way at fault (the earth lead had come loose from the plug), but anyway the next day i went and bought a simple £10 mains tester. we used it before every show for the remainder of the tour, and found several instances of missing earth and live/neutral reversed, but in all cases it was extension leads that were at fault - the wall sockets themselves were all fine.

so the moral is, i guess, test all the extensions as well, especially if it's venue-owned gear and not your own.

--------------------
Statick Audio

Thanks for the advice, I've got a couple of mates who are sparkies so I'll get one of them over to check my gear out.
Can someone link me to a good socket tester that will test for everything and is easy to use?

I tried google but I don't really know what to look for..

Cheers

This one should be a good starting point.

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There's nothing we can't face... Except for bunnies

Cheers mate

Thanks to this thread I've altered my weekly routine. Previously I'd always test my emergency lights and fire alarm on a tuesday morning; I've now added socket testing to this list.

I've come up with a theory that may or may not be right, but if it is completely wrong it can't do me any harm anyway. Basically, I reckon that terminal screws in plugs and sockets in locations that are subjected to high sound levels must be more likely to work loose over time because of the vibrations - you can also add in the vibrations from the footfall of a couple of hundred excited people - and of course the body fall of a couple of excited drunk people...

Please keep the safety advice coming.

Cheers,

Matt

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One is too many, two is about right, but three can never, ever, be enough

Mattmvb,

more relevant is the usage: being regularly plugged/unplugged, thrown into boxes/flightcases amd transported in vehicles with all the resultant periods of vibration. This handling will affect virtually any screw termination after a period of time -something that normal office mains extensions will not have to endure.

I seal mains screw terminals with a blob of nail-varnish to combat this (my original background is in electrical engineering and instrumentation and calibration adjustment trims are always sealed in this manner after any change); this seems to prevent loosening.

I also check the earth integrity of my cable very regularly (the most important electrical connection) and I visually check all my mains cables every time they are unpacked for a gig and repacked at the end of the night Cables are a rig's weakest link and safety and reputation are of paramount importance to any PA company.

get a mains tester and check your extension leads as you plug-in during set-up. buy a beer for an electrician mate and get him to check all your cables once a year...

--------------------
planet nine
lincoln, uk.

Quote Nathan:

---

Mattmvb,

I seal mains screw terminals with a blob of nail-varnish to combat this (my original background is in electrical engineering and instrumentation and calibration adjustment trims are always sealed in this manner after any change); this seems to prevent loosening.

---

Thanks for the tip Nathan.

I've also learnt another lesson the hard way. To cut a long story short I'm off to B&Q in the morning to buy some shatterproof plugs and 4-way adaptors. Fortunately nobody came to any harm but it was quite worrying to see a guitarist lose his balance whilst setting up, tread on a plug and watch half of it break off!

With regard to the cable testing, I'm fortunate to be located next door to a large theatre so no worries there - although my mains voltage can be a bit variable when they've got a big show on!

Thanks,

Matt

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One is too many, two is about right, but three can never, ever, be enough

Quote Mattmvb:

---

To cut a long story short I'm off to B&Q in the morning to buy some shatterproof plugs and 4-way adaptors.

---

Rubber plugs & sockets are your friend. They cost more, but can take far more abuse.

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There's nothing we can't face... Except for bunnies

Duraplug and Permaplug are the brands to look for, you can get them both in the larger B&Qs, but it might do you to buy from Canford as boxes of ten, etc will work out cheaper.

if you can't find the above brands, look for plugs with BS1363/A on them as the A means they comply to the more physically robust spec.

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planet nine
lincoln, uk.

You just gotta make sure that the pa and the amp are running of the same circuit. If your not sure about the wiring of the room buy yourself a proper RCD and plug it into the wall, and run everything from there. For most small things you should be grand, for bigger stuff make sure you jump up to 16a or something of the sorts as soon as you come out of the wall, and a wee distro wouldnt go a miss.

--------------------
Monty

I've just started as an house engineer at a rather small club and just last weekend the guitarist started getting shocks, didn't think it was this big of a deal and will check all the sockets right away.

But, I've got a question, there is a smoke machine hooked on the same fuse as the backline and mixer, could this be a factor in shocks? It's all metal and stands to the side of the stage.

Quote Eon:

---

But, I've got a question, there is a smoke machine hooked on the same fuse as the backline and mixer, could this be a factor in shocks? It's all metal and stands to the side of the stage.

---

Only if the guitarist is touching it as well.

Seablade

Actually if the guitar amp and fogger are plugged into the same outlet, and that outlet is not grounded, then yes this could also be a problem.

But the end result is that it is important for ALL equipment that shipped with a ground connection, be in fact grounded.

Seablade

The last guitar amp that came to one of my venues: I could see it would fail its PAT before I even got anywhere near it! The guitarist was busy stuffing the mains cable further in to the plug as the outer insulation had been stripped back far too far and the strain relief was obviously ineffectual. I opened the plug and found a 13A fuse instead of the 5A that should have been in there for the size of mains cable. And the earth wire had been cut. Not worked its way loose but cleanly cut.

I rewired it, did the rest of the PAT and handed it back to him with an explanation of why it wouldn't kill him now.

Lessons learnt: be VERY suspicious of guitar amps when it comes to electrical safety.

--------------------
There's nothing we can't face... Except for bunnies

Thanks for all this; I'm usually wireless live but our singer's been getting some nasty buzzes of late both live and in the rehearsal room. Musy pick up some RCDs and a socket tester as a matter of urgency.

This theme about singers and guitarists getting twitches from mics seems to be a recurring endemic, so I thought I'd offer some advice.

If you're getting shocks off a mic then don't just stuff a pop-shield over it, find out what's happening; either the mic is live or you're greounding yourself on the mic because something else is.

check that the earth wire is intact and connected in the plug to your PA amps and mixer, your guitar amps and any mains leads and extension blocks that supply it.

Don't take any excuses whatsoever from any guitarist who's removed an earth. None. reconnect of f*** off. Funerals are not as fun as gigs, even for Emo bands.

The only time that a plug with no earth is ok is if the appliance is "double insulated" (class2) and carries the square-inside-a-square symbol. No symbol and no earth? get someone to look at it before you use it!

Never use any mains extension that doesn't have an earth unless it is terminated in a two pin socket (like a lawnmower extension lead, see above for class2) if it has a 13A three-pin socket, appliances that require an earth could be plugged in and would not have their necessary earth (you'd be prosecuted if there was an accident).

If you are getting shocks and you're not sure what's at fault, buy or borrow a multimeter and put it on the mains (AC) setting -usu 250, 500, 1000V switch; measure between the mic grille and a water pipe or sink top or earth pin on a 13A socket, anything more than a couple of volts (high impedance floaty mains-hum pickup) is a problem and needs investigating. Try it from the bridge or strings of the guitar and see if there's any voltage. Generally anything above 50Vac will cause you a tingle when you put your lips on an earthed mic grille. the most common reading if there is a compromised earth is half normal mains voltage -about 120V. Sort it look at the earth in any mains, IEC and extension leads.

It's always a good idea to have your own 30mA RCD plug. Then you know if you touch 240V it will trip and protect you. Press the test button regularly to make sure it trips when mains is on. Those mains plug testers with three lights to show whether your earth is there and Live and Neutral are right-way-round are good too -I check all venue supplies like this.

check your mains and extension leads every time they come out of or go back into your bag/box. if there is any damage, wires showing, scuffs, cracks in plugs, etc -sort it. PAT testers do that as the first part of the test and won't even plug it into their tester if if fails the visual test (you'll get charged your test fee as a fail, and a retest fee after they've fixed it). Open up you plugs and make sure the wires are correctly terminated, looks tidy, shows no sign of overheating, fraying, fuse is correct and the screws are all tight.

If your gear looks tidy and looked over, most venues will not hassle you for PAT test certs etc. They will raise eyebrows/refuse use of gear if it looks shot. PAT test once a year is good practice for safety and hassle-free gigging, but must be supplemented by visual checks. Look on the HSE website for charts of what to be looking for (HSE think the PAT sticker movement has gone just a little to far and are quite keen for people to be educated about appliance safety as an alternative to compulsory testing in many cases)

Remember ggiging can be hard on your electrical gear, safety is paramount and your gear reliability is your gig reputation -look out for issues before they ruin your show or hurt someone.

--------------------
planet nine
lincoln, uk.

Quote Nathan:

---

This theme about singers and guitarists getting twitches from mics seems to be a recurring endemic, so I thought I'd offer some advice.

If you're getting shocks off a mic then don't just stuff a pop-shield over it, find out what's happening; either the mic is live or you're greounding yourself on the mic because something else is.

check that the earth wire is intact and connected in the plug to your PA amps and mixer, your guitar amps and any mains leads and extension blocks that supply it.

Don't take any excuses whatsoever from any guitarist who's removed an earth. None. reconnect of f*** off. Funerals are not as fun as gigs, even for Emo bands.

The only time that a plug with no earth is ok is if the appliance is "double insulated" (class2) and carries the square-inside-a-square symbol. No symbol and no earth? get someone to look at it before you use it!

Never use any mains extension that doesn't have an earth unless it is terminated in a two pin socket (like a lawnmower extension lead, see above for class2) if it has a 13A three-pin socket, appliances that require an earth could be plugged in and would not have their necessary earth (you'd be prosecuted if there was an accident).

If you are getting shocks and you're not sure what's at fault, buy or borrow a multimeter and put it on the mains (AC) setting -usu 250, 500, 1000V switch; measure between the mic grille and a water pipe or sink top or earth pin on a 13A socket, anything more than a couple of volts (high impedance floaty mains-hum pickup) is a problem and needs investigating. Try it from the bridge or strings of the guitar and see if there's any voltage. Generally anything above 50Vac will cause you a tingle when you put your lips on an earthed mic grille. the most common reading if there is a compromised earth is half normal mains voltage -about 120V. Sort it look at the earth in any mains, IEC and extension leads.

It's always a good idea to have your own 30mA RCD plug. Then you know if you touch 240V it will trip and protect you. Press the test button regularly to make sure it trips when mains is on. Those mains plug testers with three lights to show whether your earth is there and Live and Neutral are right-way-round are good too -I check all venue supplies like this.

check your mains and extension leads every time they come out of or go back into your bag/box. if there is any damage, wires showing, scuffs, cracks in plugs, etc -sort it. PAT testers do that as the first part of the test and won't even plug it into their tester if if fails the visual test (you'll get charged your test fee as a fail, and a retest fee after they've fixed it). Open up you plugs and make sure the wires are correctly terminated, looks tidy, shows no sign of overheating, fraying, fuse is correct and the screws are all tight.

If your gear looks tidy and looked over, most venues will not hassle you for PAT test certs etc. They will raise eyebrows/refuse use of gear if it looks shot. PAT test once a year is good practice for safety and hassle-free gigging, but must be supplemented by visual checks. Look on the HSE website for charts of what to be looking for (HSE think the PAT sticker movement has gone just a little to far and are quite keen for people to be educated about appliance safety as an alternative to compulsory testing in many cases)

Remember ggiging can be hard on your electrical gear, safety is paramount and your gear reliability is your gig reputation -look out for issues before they ruin your show or hurt someone.

---

Ur comments are well founded & appreciated and have been copied onto our local music web scenes cos it's an on going problem that never seems to go away!!!!
The number of amps/mixers I've come across on stage with the earth removed beggars belief. I've stopped bands playing because of this and refused to do the sound for them. At the end of the day a 5 amp fuse versus an electrocution - no contest but there are guys out there still doing this - I will not work with them and tell them at the sound check. Get an RCD from B & Q - it ain't rocket science & it's a cheaper way to save your life!!!!

There is lots to read on the 7909 website

A website dedicated to Electrical safety for Entertainment and related purposes

In particular: Bs7909:2008 The Code of practice for temporary electrical systems for entertainment and related purposes

Loads of links and advice on how to use electricity well.

http://www.7909.org.uk

Don't forget if you think a venue is unsafe apply to the local council for a licensing review asking for a section 182 condition on electrical safety to be added!

Edited by Stewart Newlands (01/08/09 05:54 PM)

Was talking to My Mate Ted last night at a party & he told me the story of a recent near disaster he experienced.

They use a tester etc and normally have no probs with mains.
They were playing an outdoor gig and some clown had mis-wired the three phase supply so that two phases were hooked up to phase and neutral, givinbg a potential of 460 volts across the supply.

Ted said his amp had never sounded so good for the first set, then all of a sudden everything was smoking and he was flopping around like a beached herring, still holding the offending (lethal) guitar lead. Fortunately the bass player put his foot on ted`s hand holding the lead and got him off it, but the backline was fried and poor old Ted was in a bad way for some time after.

And of course he and a mate have now gone into business making this cool little box that measures the potential between ALL connections (not just phase and earth and neutral & earth)and shuts the supply down if anything exceeds 260 volts.
So far three PA hire companies have bought and I suspect he will get a lot of other customers.
Around £100, which is way cheaper than the next available thing at about £400

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Me? But I`m such a loveable old bugger!

Hi Ivan, so do I google "My mate Ted.co .uk" or will you spill the beans?Dave

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My head hurts!

This has happened on a number of occasions with our band most recently on Saturday night. Our lead vocalist was receiving shocks on his microphone. The vocal is the only thing that goes into the mixer since it was such a small venue and we don't own any bass bins yet.

The mixing desk and power amp was plugged into a Surge Protected 4 way adapter into what looked like a slightly dodgy plug, but we have played there on many occasions and this was the first time this happened.

We then just plugged in the mixer into the plug and it worked fine.

Our gear has been lugged in and out of vans and cars for nearly 7 years now, with updates and changes of course, so I can see an aspect of that affecting things, but the mixing desk is usually kept in good nick.

Just a few quick questions, because this has been plaguing us for a while, and myself.

1. Are surge protected 4 way plugs recommended? I have heard rumors they are not good for powering amps etc. So just to confirm before i go out and buy some

2. Is using many separate wall sockets the best method to combat electrical shocks?

Quote adamb1026:

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This has happened on a number of occasions with our band most recently on Saturday night. Our lead vocalist was receiving shocks on his microphone. The vocal is the only thing that goes into the mixer since it was such a small venue and we don't own any bass bins yet.

The mixing desk and power amp was plugged into a Surge Protected 4 way adapter into what looked like a slightly dodgy plug, but we have played there on many occasions and this was the first time this happened.

We then just plugged in the mixer into the plug and it worked fine.

Our gear has been lugged in and out of vans and cars for nearly 7 years now, with updates and changes of course, so I can see an aspect of that affecting things, but the mixing desk is usually kept in good nick.

Just a few quick questions, because this has been plaguing us for a while, and myself.

1. Are surge protected 4 way plugs recommended? I have heard rumors they are not good for powering amps etc. So just to confirm before i go out and buy some

2. Is using many separate wall sockets the best method to combat electrical shocks?

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Surge protection will not protect against dodgy earths - which is almost certainly what was happening here.

I suggest you get yourself a socket tester - you can get them from Maplins - which will let you see if the wiring in the socket is as it should be. Any problems, then don't use that socket and tell the venue management that they have a serious problem which needs fixing pronto.

But that's not enough. Always connect to sockets using an RCD current dumper - widely available from DIY multistores. And if you have several mains extensions daisy-chaining then put an RCD on each link. RCDs only cost a few pounds and could save someone's life.

There's no advantage in connecting to multiple wall sockets as long as you're not overloading one socket. In fact, using multiple sockets raises the possibilities of introducing ground/earth loops.

Quote adamb1026:

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This has happened on a number of occasions with our band most recently on Saturday night. Our lead vocalist was receiving shocks on his microphone. The vocal is the only thing that goes into the mixer since it was such a small venue and we don't own any bass bins yet.

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Does your lead vocalist play guitar?

The body of the microphone will be connected to the ground / earth of the mixing desk. If the mic body was at a potential that would cause shocks, it's likely that the case of the mixer would be at this same potential. Did anybody notice any tingles when touching the mixer?

In order to get a shock, you have to be touching two things at different potentials at the same time. The mic is one of those things; to be fair to it, the mic is usually not the culprit as it is usually at ground potential.

99% of the time, the problem is with a singing guitarist's amp. Despite the title of this thread, the mic is very rarely the cause.

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There's nothing we can't face... Except for bunnies

Quote Sheriton:

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Quote adamb1026:

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This has happened on a number of occasions with our band most recently on Saturday night. Our lead vocalist was receiving shocks on his microphone. The vocal is the only thing that goes into the mixer since it was such a small venue and we don't own any bass bins yet.

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Does your lead vocalist play guitar?

The body of the microphone will be connected to the ground / earth of the mixing desk. If the mic body was at a potential that would cause shocks, it's likely that the case of the mixer would be at this same potential. Did anybody notice any tingles when touching the mixer?

In order to get a shock, you have to be touching two things at different potentials at the same time. The mic is one of those things; to be fair to it, the mic is usually not the culprit as it is usually at ground potential.

99% of the time, the problem is with a singing guitarist's amp. Despite the title of this thread, the mic is very rarely the cause.

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Thanks Mike, will use your advice

Also, do you have any links to where I could buy a RCD damper? I've just been looking on maplins and cant seem to find one.

Thanks again


Sorry, should have been more specific, he was receiving shocks to his lips rather than the casing. I don't think he received any shocks from the desk.

And yes he does play guitar . Out of my ignorance, how does his amp become the problem?

Some of the venues we play really don't accommodate bands well. They just find an empty space and tell us to setup there. Since the smoking ban has come into our country, in one venue, we basically play beside the door to where people have to get outside. We used to take the whole area, but now since we are squeezed to one side, my bass head has almost become a weapon lol

Edited by adamb1026 (06/10/09 10:56 AM)

Quote adamb1026:

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Also, do you have any links to where I could buy a RCD damper? I've just been looking on maplins and cant seem to find one.

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Not sure where the word damper came from but it's this kind of thing that you're after. I can't vouch for that particular model as I've never used one but any DIY store will sell you an RCD also.

Quote adamb1026:

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And yes he does play guitar . Out of my ignorance, how does his amp become the problem?

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A lot of misguided guitarists cut the mains protective earth in their amp, believing it to be the way to eradicate hum from their rig. Have a read right through this thread for more details. I know it's long, but it may just save someone's life. Seriously. Far too many guitarists have been killed through this stupidity. Get all of your kit PAT tested regularly if you don't already do so. That will show up any potentially dangerous faults like a lifted earth.
And if your guitarist has disconnected the earth, beat him around the head with the amp until he sees sense. There is never EVER any reason for doing so. Under any circumstances. EVER.

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There's nothing we can't face... Except for bunnies

I dont think he has cut the earth, but I'll check it out in any case and give him a good smack if he has.

Thanks very much for all of your help.

Must go for a walk down to Maplins

Edited by adamb1026 (06/10/09 11:25 AM)

Quote adamb1026:

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I dont think he has cut the earth, but I'll check it out in any case and give him a good smack if he has.

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A bad socket can cause a similar effect. Pretty much if the ground is disconnected ANYWHERE in the power chain, this NEEDS to be fixed. No exceptions. This is why people are suggesting the socket tester, as it allows you to quickly and easily see if a socket is good, never assume it is.

Seablade

If he's getting shocks to his lips, there's a possibility that it was static electricity! (NB. That doesn't mean you can ignore all the other stuff we've written! )

I was once very agressively berated by a singing guitarist when he got a lip-shock. I knew all the gear was OK, but checked it anyway - no problems found, all earths good. Eventually I tracked it down to him wearing some synthetic materials and some synthetic-soled trainers. He was his own little Van der Graff Generator and then earthed himself through the mic capsule basket and its connections. That's not to take away from the static shock you get though; it happened to me once and it ain't funny!

Quote:

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1. Are surge protected 4 way plugs recommended? I have heard rumors they are not good for powering amps etc. So just to confirm before i go out and buy some

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Not particularly, at best the protection is marginal, they often fail silently and they can contaminate the power ground (which really shouldn't matter, but often does, particularly with unbalanced gear).

They only do what any competent power supply designer should be doing anyway.

Quote:

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2. Is using many separate wall sockets the best method to combat electrical shocks?

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Nope, using a few sockets that you have tested and know to be correctly wired and earthed, and keeping all your gear in good repair is the best way to avoid shocks, and RCDs are (while not foolproof) a good way to increase your chances of surviving one.

A shock should be an indication that something (several things) has gone badly wrong, and should always be a signal to stop and fault find then fix whatever the problem is (And then review your maintenance, it should never have gotten that far).

Sorry, but IMHO a shock is almost always an indication that someone has screwed up, as it really should require at least 2 faults to cause one.

Regards, Dan.

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Audiophiles use phono leads because they are unbalanced people!

Quote Mike Charles:

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If he's getting shocks to his lips, there's a possibility that it was static electricity! (NB. That doesn't mean you can ignore all the other stuff we've written! )

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lol well it has happened on a few occasions, so through reading this topic, I can pretty much confirm it is the plugs , but I will keep that in mind next time it happens.

Thanks dmills on the advice especially about surge protectors.

We do have an large amount of gear. Particularly our lead guitarist has 8 pedals through a Behringer 12 set pedal board, which I thought was maybe could be a concern for future electric problems. Again excuse my ignorance if it isn't.

I think I'm going to persuade him and invest in a hard case for the mixer and power amp after telling him about this and to genuinely keep his mixer in good nick .

if this mic-grille shock has happened multiple times in different venues, it suggests that the problem might be a fault of your band's gear somewhere (the common factor).

If you have a multimeter, set it to its 250V, 500V or 1000V AC setting and measure between the mic grille and a radiator or water pipe) If there's more that a couple of Volts then you could have a mains earth-issue in your PA or mixer supply.

If that's normal, but measuring between your guitarist's bridge or strings and the radiator/pipe gives you a reading, then the issue is with the guitar amp or mains plug/cable supplying it. What you're looking for is voltage on something that should be earthed.

Post or PM me if you need further help.
Nathan.

>

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planet nine
lincoln, uk.

That's great Nathan thanks.

My dad should have a multimeter lying about in the garage somewhere who is a qualified electrician, so I can tell him about your technique and he can guide me a bit further as well.

Appreciate the help.

establish that there is an issue between bridge and mic grille first by measuring directly between them, if it reads about 120V approach with caution! This will rule out a static electricity issue, then measure to each from the water pipe. Bear in mind that this trick can also dig out problems with installed wiring earths, and also that not all central heating systems are earthed (although they should be bonded).

I usually find that its an earth problem in a mains cable leading to the guitar amp, but this method has traced problems to loose earths in extension leads supplying the PA mixer too.

>

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planet nine
lincoln, uk.

Yes, you need to be very logical and thorough when trying to track down a potential satefty earth problem like this.

There are lots of earth interconnections between the wall socket and the guitar, and every single one has to be good to be safe... so work through carefully and logically fromt he wall socket.

Start with a mains plug tester, as recommended above to check the wall socket(s) and do that at every single venue you use every single time you use it. I lost count years ago of how many tims I've found duff, unsafe sockets in public venues.

If the socket is safe and properly earth bonded, then work through all your mains extension boards and extension cables. The first check -- and one you should do everytime you pack and unpack you gear is a visual one, looking for cracks, cuts or crushes to the cable or any damage to the plugs of sockets -- any sign of physical damage requires careful investigation before use.

You can test the extension cables and boards with a multimeter but a quick and easy way is to use the mains socket tester again by plugging the extension cable of distribution board into the wall socket and then plugging the tester into each socket on the board or cable to check they are all okay. It is possible for individual sockets in extension boards to fail too...

If all the mains distribution stuff tests fine, then you'll need to move on to the IEC mains cables or the equipment itself if it uses captive mains leads. This is where you'll need to use a multimeter with a resistance or continuity mode. Don't plug the IEC leads into the mains -- instead put one probe onto the large mains plug earth pin and the other into the offset central earth receptacle on the IEC socket. You should get a reading of zero ohms or 100% continuity.

If it's a captive cable, then check between the mains plug earth pin and the metalwork on the equipment -- unless the label has the double-insulated symbol (a box within a box), in which case you won't get any continuity at all, by design.

Static shocks can be unsettling but are rarely any real problem and perversly do indicate that the system is probably properly earthed!

One way to determine whether you have a serious safety earth problem or just static shocks is to find out if the shock happens constantly or just briefly now and again.

A safety earth problem will mean that every single time someone bridges between something properly earthed (usually the mic) and the faulty part of the system (usually the guitar amp), they will get a shock (or, hopefully, trip the RCD!) and that the shock continues for as long as they are in contact (or until the RCD trips).

If it's a static shock, the first time they touch anything earthed they will discharge themselves and feel the brief moment of shock but thereafter they won't feel anything while they remain in contact. And if they touch it again a few moments later they won't feel a second shock either.

Only after they've shuffled around on the carpet or danced about to recharge their clothes will they build up their own static potential enough to feel a shock when discharging again through something earthed.

Hugh

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Technical Editor, Sound On Sound

Hugh,

As this topic comes up time and time again, and as a lot of us return to the same venues, would it be with our rights or the rules of the forum to start "naming and shaming" the venues that have dodgy supplies and such like.

I've been touring now for quite some time and there are venues out there that I'm always very dubious about pluging even my phone charger into, but those where I have even refused to plug into the heavier mains supplies.

One, which shall for the mean time remain as Venue X had 2x 32a single ceeforms on each side of the stage, mounted on the floor. Both were live-neutral reversed and one was so badly damaged that I couldn't even plug my rack in (we have EMO distro in all our racks which has those handy neon indicators)

When speaking to the in-house electrician about why I wasn't about to plug my gear in, he said "Everybody uses them, it's ok for them, it can be ok for you!"

This isn't just a small pub somewhere, this is a major national venue. We shouldn't be taking this kind of attitude and I refuse to go back and have mentioned it to the relevant authorities, but I think as most of us know, this can't happen again.

PM me if you want to chat about how we do this

Cheers

Ben

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The early bird may catch the worm, but it's the second mouse that gets the cheese!

I can certainly understand your frustration, Ben, but I think I'll need to take some advice before allowing a name and shame thread... tempting though it would be.

Leave it with me for a few days please.

Hugh

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Technical Editor, Sound On Sound

Quote Mike Charles:

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If he's getting shocks to his lips, there's a possibility that it was static electricity! (NB.

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I'll tell you now, I am very susceptible to static - I even have to be careful when I get out the car, by earthing myself first, and I'm not kidding either. I regularly get shocks from mic's, and all my kit properly earthed/pat tested (which I did as a result of having read a thread like this years ago).

Some people are just unlucky.

Quote Hugh Robjohns:

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I can certainly understand your frustration, Ben, but I think I'll need to take some advice before allowing a name and shame thread... tempting though it would be.

Leave it with me for a few days please.

Hugh

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Of course!!

I will say that 99% of venues we go to are spot on and I wouldn't have a word said against them.

I understand it's very much a case of the venue could be the safest place to plug into but a bands gear is shot to bits, and vice versa.

It just seems to me that so many legislations are out there now to stop this sort of thing happening, it happens on such a regular basis.

This may be slightly off topic, but when, in a time when health and safety is killing our industry, is a lack of health and safety potentially risking our lives?

I'm sorry if I seem to have come across all stroppy about this, but judging by the number of posts here, it's obviously a major concern

Ben

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The early bird may catch the worm, but it's the second mouse that gets the cheese!