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Mattmvb



Joined: 29/03/08
Posts: 49
Loc: Birmingham, UK
Re: Well, yeah, again, electric shocks from mics !! new [Re: ghc]
      #664235 - 05/10/08 10:37 PM
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

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


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Nathan



Joined: 13/09/04
Posts: 1882
Loc: lincolnshire government experi...
Re: Well, yeah, again, electric shocks from mics !! new [Re: Mattmvb]
      #665127 - 08/10/08 04:48 AM
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.


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Mattmvb



Joined: 29/03/08
Posts: 49
Loc: Birmingham, UK
Re: Well, yeah, again, electric shocks from mics !! new [Re: Nathan]
      #665783 - 10/10/08 12:24 AM
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

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


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Sheriton



Joined: 27/01/03
Posts: 1555
Loc: Leicester, UK
Re: Well, yeah, again, electric shocks from mics !! new [Re: Mattmvb]
      #665819 - 10/10/08 08:29 AM
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.

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


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Nathan



Joined: 13/09/04
Posts: 1882
Loc: lincolnshire government experi...
Re: Well, yeah, again, electric shocks from mics !! new [Re: Sheriton]
      #666335 - 12/10/08 10:04 AM
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.

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


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Steven Montgomery



Joined: 06/06/06
Posts: 39
Loc: Northern Ireland
Re: Well, yeah, again, electric shocks from mics !! new [Re: ghc]
      #674267 - 02/11/08 09:53 PM
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


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Eon



Joined: 11/05/09
Posts: 2
Re: Well, yeah, again, electric shocks from mics !! new [Re: ghc]
      #733859 - 11/05/09 04:41 PM
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.


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seablade



Joined: 21/11/04
Posts: 3942
Re: Well, yeah, again, electric shocks from mics !! new [Re: Eon]
      #733866 - 11/05/09 04:54 PM
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


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seablade



Joined: 21/11/04
Posts: 3942
Re: Well, yeah, again, electric shocks from mics !! new [Re: seablade]
      #733870 - 11/05/09 05:12 PM
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


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Sheriton



Joined: 27/01/03
Posts: 1555
Loc: Leicester, UK
Re: Well, yeah, again, electric shocks from mics !! new [Re: ghc]
      #733893 - 11/05/09 07:06 PM
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


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Ian Savage



Joined: 16/12/07
Posts: 611
Re: Well, yeah, again, electric shocks from mics !! new [Re: ghc]
      #733954 - 11/05/09 10:46 PM
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.


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Nathan



Joined: 13/09/04
Posts: 1882
Loc: lincolnshire government experi...
Re: Well, yeah, again, electric shocks from mics !! new [Re: Ian Savage]
      #751239 - 09/07/09 07:43 AM
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.


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eggle5



Joined: 15/10/07
Posts: 52
Re: Well, yeah, again, electric shocks from mics !! new [Re: Nathan]
      #757821 - 27/07/09 11:34 PM
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!!!!


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Stewart Newlands



Joined: 27/03/08
Posts: 11
Re: Well, yeah, again, electric shocks from mics !! new [Re: ghc]
      #759061 - 01/08/09 05:51 PM
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)


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IvanSC



Joined: 08/03/05
Posts: 7786
Loc: UK France & USA depending on t...
Re: Well, yeah, again, electric shocks from mics !! new [Re: ghc]
      #759147 - 02/08/09 07:33 AM
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

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


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turbodave



Joined: 25/04/08
Posts: 2316
Loc: derbyshire uk
Re: Well, yeah, again, electric shocks from mics !! new [Re: ghc]
      #759158 - 02/08/09 09:07 AM
Hi Ivan, so do I google "My mate Ted.co .uk" or will you spill the beans?Dave

--------------------
My head hurts!


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adamb1026



Joined: 05/10/09
Posts: 60
Loc: Belfast, N.Ireland
Re: Well, yeah, again, electric shocks from mics !! new [Re: ghc]
      #776231 - 05/10/09 09:54 PM
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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Mike Stranks
active member


Joined: 03/01/03
Posts: 3600
Loc: Oxford, UK
Re: Well, yeah, again, electric shocks from mics !! new [Re: adamb1026]
      #776313 - 06/10/09 08:44 AM
Quote adamb1026:

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?




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.


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Sheriton



Joined: 27/01/03
Posts: 1555
Loc: Leicester, UK
Re: Well, yeah, again, electric shocks from mics !! new [Re: adamb1026]
      #776333 - 06/10/09 09:35 AM
Quote adamb1026:

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.





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.

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


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adamb1026



Joined: 05/10/09
Posts: 60
Loc: Belfast, N.Ireland
Re: Well, yeah, again, electric shocks from mics !! new [Re: Sheriton]
      #776356 - 06/10/09 10:55 AM
Quote Sheriton:

Quote adamb1026:

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.





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.




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)


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Sheriton



Joined: 27/01/03
Posts: 1555
Loc: Leicester, UK
Re: Well, yeah, again, electric shocks from mics !! new [Re: adamb1026]
      #776360 - 06/10/09 11:14 AM
Quote adamb1026:


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.





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:


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





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.

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


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adamb1026



Joined: 05/10/09
Posts: 60
Loc: Belfast, N.Ireland
Re: Well, yeah, again, electric shocks from mics !! new [Re: ghc]
      #776367 - 06/10/09 11:24 AM
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)


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seablade



Joined: 21/11/04
Posts: 3942
Re: Well, yeah, again, electric shocks from mics !! new [Re: adamb1026]
      #776418 - 06/10/09 12:59 PM
Quote adamb1026:

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.




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


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Mike Stranks
active member


Joined: 03/01/03
Posts: 3600
Loc: Oxford, UK
Re: Well, yeah, again, electric shocks from mics !! new [Re: ghc]
      #776424 - 06/10/09 01:17 PM
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!


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dmills



Joined: 25/08/06
Posts: 2293
Re: Well, yeah, again, electric shocks from mics !! new [Re: ghc]
      #776568 - 06/10/09 09:13 PM
Quote:


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




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:


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




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.

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


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adamb1026



Joined: 05/10/09
Posts: 60
Loc: Belfast, N.Ireland
Re: Well, yeah, again, electric shocks from mics !! new [Re: Mike Stranks]
      #777113 - 08/10/09 12:19 PM
Quote Mike Charles:

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! )




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 .


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Nathan



Joined: 13/09/04
Posts: 1882
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Re: Well, yeah, again, electric shocks from mics !! new [Re: adamb1026]
      #777579 - 09/10/09 11:30 PM
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.

>

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


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adamb1026



Joined: 05/10/09
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Loc: Belfast, N.Ireland
Re: Well, yeah, again, electric shocks from mics !! new [Re: ghc]
      #778709 - 13/10/09 06:52 PM
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.


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Nathan



Joined: 13/09/04
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Re: Well, yeah, again, electric shocks from mics !! new [Re: adamb1026]
      #779694 - 17/10/09 10:36 AM
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.

>

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


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Hugh RobjohnsAdministrator
SOS Technical Editor


Joined: 25/07/03
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Re: Well, yeah, again, electric shocks from mics !! new [Re: Nathan]
      #779720 - 17/10/09 11:32 AM
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

--------------------
Technical Editor, Sound On Sound


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the muppet



Joined: 27/08/04
Posts: 1010
Loc: with my head stuck up my a£se...
Re: Well, yeah, again, electric shocks from mics !! new [Re: Hugh Robjohns]
      #796104 - 14/12/09 03:27 PM
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

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


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Hugh RobjohnsAdministrator
SOS Technical Editor


Joined: 25/07/03
Posts: 20797
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Re: Well, yeah, again, electric shocks from mics !! new [Re: the muppet]
      #796132 - 14/12/09 05:31 PM
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

--------------------
Technical Editor, Sound On Sound


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TheChorltonWheelie



Joined: 22/09/09
Posts: 969
Re: Well, yeah, again, electric shocks from mics !! new [Re: Mike Stranks]
      #796142 - 14/12/09 06:05 PM
Quote Mike Charles:

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




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.


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the muppet



Joined: 27/08/04
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Re: Well, yeah, again, electric shocks from mics !! new [Re: Hugh Robjohns]
      #796190 - 14/12/09 10:46 PM
Quote Hugh Robjohns:

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




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

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


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Hugh RobjohnsAdministrator
SOS Technical Editor


Joined: 25/07/03
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Re: Well, yeah, again, electric shocks from mics !! new [Re: the muppet]
      #796195 - 14/12/09 10:59 PM
Quote the muppet:

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 discussed it with Ian, and as you probably suspected, the word is no. It's just too risky if someone doesn't get their facts straight (accidentally or even deliberately), or the venue improves and the thread isn't updated. It would leave SOS open to being sued, and that really wouldn't be a good idea.

So, sorry. But no. I think the best course of action would simply be to bring any venue with poorly maintained electrical supplies to the attention of the appropriate regulatory bodies -- the local council or the HSE.

Hugh

--------------------
Technical Editor, Sound On Sound


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feline1
active member


Joined: 23/06/03
Posts: 4086
Loc: Brighton, UK
Re: Well, yeah, again, electric shocks from mics !! new [Re: Hugh Robjohns]
      #796271 - 15/12/09 11:37 AM
Quote Hugh Robjohns:

Quote the muppet:

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 discussed it with Ian, and as you probably suspected, the word is no. It's just too risky if someone doesn't get their facts straight (accidentally or even deliberately), or the venue improves and the thread isn't updated. It would leave SOS open to being sued, and that really wouldn't be a good idea.

So, sorry. But no. I think the best course of action would simply be to bring any venue with poorly maintained electrical supplies to the attention of the appropriate regulatory bodies -- the local council or the HSE.

Hugh




Indeed - it's not a magazine's job to police electrical safety in the field.
It would be about like witnessing an accident and phoning your local newspaper about it instead of dialling 999 for an ambulance.
If someone does report electrical problems promptly to the local council or HSE, then those bodies should fairly swiftly see that they are dealt with in any case, so the problem should not exist for very much longer.

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


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chris...
active member


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Posts: 4487
Re: Well, yeah, again, electric shocks from mics !! new [Re: ghc]
      #800134 - 02/01/10 05:06 PM
OK, so whilst rehearsing today, bass player experienced mild shock from mic. So we plugged the socket tester into the "garden" mains extension lead his bass combo was plugged into. Earth missing. Opened up the extension lead's plug and socket, expecting to find a loose/damaged earth connection. But no...

It was 2-core mains cable. Never had an of earth any kind (!)

Is this sort of thing common ? Are all lawnmowers double-insulated, or something ?


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dmills



Joined: 25/08/06
Posts: 2293
Re: Well, yeah, again, electric shocks from mics !! new [Re: chris...]
      #800150 - 02/01/10 06:20 PM
Quote Chris Edwards:


It was 2-core mains cable. Never had an of earth any kind (!)
Is this sort of thing common ? Are all lawnmowers double-insulated, or something ?




Basically, yes!

There are electrical safety "issues" with taking the earth outside the building due to the way most domestic supplies in the UK are earthed.

Due to this most garden appliances are double insulated and most have 2 core cables. I am however shocked (SORRY!) to discover that an extension cable (presumably with a 13A socket on the end) is being supplied wired with 2 core.

You do find 2 core cables made for garden use with lawnmower connectors on them (which are inherently 2 pin), and I hope that lethal extension came from some numpty modifying such a lead rather then being a commercial product.

When powering outdoor gigs from a building supply which is suspected to be TN-C-S or (PME) connected (the normal way these days), the safest way to do it is to bring out the live and neutral and derive a TT supply locally (with an RCD and local earth connection) or to use an isolating transformer (with local spike) and derive a TN-S supply with your own transformer.

Both require some thought and some specialist tools to test and verify for safety, and the issue is largely ignored by a lot of folks, but there is a right way and a wrong way to do these things.....

Regards, Dan.

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


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chris...
active member


Joined: 12/03/03
Posts: 4487
Re: Well, yeah, again, electric shocks from mics !! new [Re: dmills]
      #800157 - 02/01/10 06:42 PM
Quote dmills:

most garden appliances are double insulated and most have 2 core cables.




Ah, right.


Quote:

I am however shocked (SORRY!) to discover that an extension cable (presumably with a 13A socket on the end) is being supplied wired with 2 core.

You do find 2 core cables made for garden use with lawnmower connectors on them (which are inherently 2 pin), and I hope that lethal extension came from some numpty modifying such a lead rather then being a commercial product.




I'm not familiar with this 2-pin lawnmower connector. My own tiny flymo simply has a regular 3-pin mains plug.

Anyway, back to the extension lead in question. Yes, it had a 13A 3-pin mains plug at one end, and a 3-pin socket on the other. The bass player remembers buying it from B&Q some years ago - ie. not modified by a numpty...

This experience made me wonder if such extensions (2-core mains cable, with 3-pin plug/socket) are common in the gardening fraternity - with the understanding they're only to be used with double-insulated kit.

But I take it you're confirming this is not the case ?

Ta

PS - incase I wasn't very clear, this was an indoor rehearsal. The "garden" extension simply came to hand easily.


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dmills



Joined: 25/08/06
Posts: 2293
Re: Well, yeah, again, electric shocks from mics !! new [Re: chris...]
      #800159 - 02/01/10 06:56 PM
Quote Chris Edwards:


But I take it you're confirming this is not the case ?





Indeed, anything with a 13A socket on it (with very few specialist exceptions (of which an extension lead is never one)), should have a earth connection.

This is the sort of thing that begets two core cables for garden use:
http://www.maplin.co.uk/Module.aspx?moduleno=13176

Note that a two core cable with a 13A PLUG on one end and a female one of these on the other is totally standard (and safe) as a cable for things like some flymo lawnmowers. What you should never see is such a cable with a SOCKET on it.

I would suspect someone of modifying a lawnmower cable, but I suppose anything is possible.

Regards, Dan.

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


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