I was working at a church hall the other night, iPod disco plus folky band. Night went fine except for an odd occurance with my LED pars.

They are Thoman Stairvilles, been out only once before, only two months old apprx. I mounted 4 on a stand and fed them with one IEC that was daisy chained to all four, plugged into the gang supplying control (another socket supplied all amps and other stage lights).

I was focusing the 4 stand mounted and every now and then I felt a little tingle in my fingers. Touching stand was fine, touching light casing was fine, touching some of the par can casing screws while other hand was touching another can casing/screw was when I felt tingle.

The two mains sockets used had RCDs in place (mine). Any ideas why this electric shock was happening?

Note the cans have not yet been PAT tested. Also, I am aware that control and amps should ideally be powered from same socket (or same ring), it was to save cable run.

Thanks for any help you can give.

Not sure about LED pars, but on the incandescent type the earth cable is usually connected to the body somewhere near the top of the can, with an earth bond between the top part and the bottom part. Sounds like you might have had a slight leakage there.

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Gear List: reverse only.

LED cans sometimes have notoriously high leakage current, and if the earth is faulty on one then touching it while also touching an earthed one will result in a tickle more often then not with cheap cans.

Dicky earth connection somewhere would be my guess, stick them on the PAT machine then fix the bonding on which ever one is faulty (Don't forget that the fault could be in the power distribution).

Regards, Dan.

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Audiophiles use phono leads because they are unbalanced people!

+ 1 for getting the lanterns and all of your extension leads and adaptors properly tested, but I would also recommend carrying a decent test plug (one which also tests earth loop impedance) and checking supplies before connecting to them.
Here's the type I use;
http://cpc.farnell.com/martindale-electric/ez150/non-trip-earth-loop-imped ance-indicator/dp/IN04254
don't waste your money on the cheaper '3 neon' type.

Quote pk.roberts:

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+ 1 for getting the lanterns and all of your extension leads and adaptors properly tested, but I would also recommend carrying a decent test plug (one which also tests earth loop impedance) and checking supplies before connecting to them.
Here's the type I use;
http://cpc.farnell.com/martindale-electric/ez150/non-trip-earth-loop-imped ance-indicator/dp/IN04254
don't waste your money on the cheaper '3 neon' type.

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Just out of interest... why d'you consider them a waste of money?

Although they will give a rough indication that Line, Neutral and Earth are connected to the correct terminals on the socket, they will give no indication as to the quality of the earth; there has to be a large earth loop impedance before they will indicate any sort of problem and so, I believe, they can actually give a false sense of security.
As an example (non music related I'm afraid), an elderly friend who is a model engineer told me he was having problems with the lathe in his shed; it felt a bit "fuzzy and tingly' he explained. He had plugged in one of the 'neon' type testers and it indicated everything was fine. When I plugged in the newer kind of tester(the one in my link) it showed quite a large reading on the earth loop and further investigation revealed a loose and corroded terminal in a junction box. Had he ever had a live to earth fault, I doubt very much that a fuse would have gone. If you prefer a more 'regulatory' reply, the newer type of tester is also specified in BS7909 which I think is a reasonable and practical standard to work to and certainly not onerous for installations of less than 6kW.

Quote pk.roberts:

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Although they will give a rough indication that Line, Neutral and Earth are connected to the correct terminals on the socket, they will give no indication as to the quality of the earth; there has to be a large earth loop impedance before they will indicate any sort of problem and so, I believe, they can actually give a false sense of security.
As an example (non music related I'm afraid), an elderly friend who is a model engineer told me he was having problems with the lathe in his shed; it felt a bit "fuzzy and tingly' he explained. He had plugged in one of the 'neon' type testers and it indicated everything was fine. When I plugged in the newer kind of tester(the one in my link) it showed quite a large reading on the earth loop and further investigation revealed a loose and corroded terminal in a junction box. Had he ever had a live to earth fault, I doubt very much that a fuse would have gone. If you prefer a more 'regulatory' reply, the newer type of tester is also specified in BS7909 which I think is a reasonable and practical standard to work to and certainly not onerous for installations of less than 6kW.

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Thank 'e kindly. Helps us all to know why it's worth spending a bit more on a tester such as you recommend.