Electric shocks

[woodster]

Hi all,

Right, here's the setup.... In the back of my rack i have a 6-way strip which i usually plug into an extension reel which in turn is plugged into the wall via a plug-in RCD.

This week at rehearsals, i've been getting shocks on my lips from the mic when my hands touch my strings. I made sure phantom power was switched off on the mixer and tried various things such as different mic leads or different channels but only got rid of the shocks when i removed my extension reel and plugged straight into the wall.

I've checked the wiring of the reel and all looks fine. What am i missing here?

Thanks in advance...

[Buzz]

I'd say the extension lead is faulty and the ground connection has been broken, but there's also a good chance that other equipment is at fault too, not just the mixer or mic, I'm thinking about your amp and rack equipment.

That's just a guess mind you, however, what I can say is stop playing around with the damn thing and STOP USING THE EXTENSION, it doesn't take a lot of 'leccy to kill you if it travels down through your heart.

Edited December 22, 2008 by Buzz

[BigAlonBass]

£10 for a new extension-Staying alive and keeping on playing Bass-priceless!

[woodster]

A new extension reel is top of my Santa list so hopefully that'll sort it. I'll just add that i'm ALWAYS connected to an RCD as i have a healthy respect for electricity.

[martthebass]

Often wondered about this 'shock'.

A couple of pubs I used to play - I was always guaranteed to get Mic shocks. Only happened at these 2 - despite using RCD extension. Pi**ed me off so much I went wireless - never looked back.

[Jean-Luc Pickguard]

I've had that when the bass amp & the PA are on different circuits. The shocks cease when both are plugged into the same extension.

[thepurpleblob]

An RCD won't save you from everything. I think a good investment is one of those socket testers that confirms a socket is correctly wired - you can try it at various points down your wiring chain. If you're really paranoid you can/should get everything PAT tested - there are some engineers who specialise in musician equipment.

[Rich]

+1 for the socket tester, these are a damn good idea.

[quote name='woodster' post='361389' date='Dec 22 2008, 08:50 PM']A new extension reel is top of my Santa list so hopefully that'll sort it. I'll just add that i'm ALWAYS connected to an RCD as i have a healthy respect for electricity.[/quote]
Please, beat the beardy to it and buy one NOW, before you play next. The next shock might be a big bastard, and I do NOT want to see your R.I.P. thread on here

[woodster]

That's a good point but thankfully i don't have a gig till new year's eve now so if beardy is a little sloppy and forgets my reel, Santa 'B and Q' Clause will be getting a hasty visit!

[Dood]

As mentioned above, check everything and don't rule out that there could be something wrong with the mains in the venue as well as the equipment you are using. It does sound like you are having an earth loop issue. It sounds like the earthing of your amp is not the same as your earthing on your PA. The difference in voltage is causing the shock..

oh heck... here's someone who can explain it a lot better than I! I have played in many a venue where this is a problem!

[url="http://en.wikipedia.org/wiki/Ground_loop_(electricity)"]http://en.wikipedia.org/wiki/Ground_loop_(electricity)[/url]

[Stu-khag]

+1 for socket testers.
Ive got a martindale which has served me well.

[woodster]

That's a great description, thanx Dood

[Huge Hands]

Take a mic lead with you that has pin 1 (shield) disconnected at one end.

This will cure your problem.

It's due to small potential differences in the ground paths between your mic mixer and your amplifier. All you are doing is "lifting" the ground path for your mic.

As a previous poster said, plugging your PA and backline into the same power outlet (if possible) will help.

[woodster]

I'll certainly do that!

Thanx HH

[stingrayfan]

[quote name='Huge Hands' post='361925' date='Dec 23 2008, 01:07 PM']As a previous poster said, plugging your PA and backline into the same power outlet (if possible) will help.[/quote]
Often the solution - esp in rehearsal places where the leccy supply is dubious!

[William James Easton]

i davise anyone not to use these cheap white plastic 4-ways. they are not worth the risk and companys are not allowed to use them in offices any more( well thats what i've been told) by a good extension reel for around 15 lizzies with RCD buiilt in. cant go wrong (i hope)

[sixshooter]

I got someone to put together a piece of wood with a Fuse box with RCD's and 4 sockets. Now everything, (except the lighs), plugs into this so there is no diferetial between equipment. Cost about £60, worth every penny!

[6stringbassist]

A socket tester is only good if you know what you're looking at, and it won't tell you if the neutral and earth are reversed.

Best to get a good RCD extension lead, it shouldn't work if there's no earth, and should trip if there's the slightest 30mA leakage to earth, they work on the principle of what goes out should come back, so will trip if there's the slightest difference between current going out through it and coming back through the neutral.

[Weird War]

[quote name='6stringbassist' post='362066' date='Dec 23 2008, 03:31 PM']Best to get a good RCD extension lead, it shouldn't work if there's no earth, and should trip if there's the slightest 30mA leakage to earth, they work on the principle of what goes out should come back, so will trip if there's the slightest difference between current going out through it and coming back through the neutral.[/quote]

I want to get RCD protection for gigs but need to travel light (as I'm on foot 90% of the time!) - would I be best getting a RCD socket rather than an extension lead or cable reel? Saw one in B&Q today for a tenner, looked a bit plastic but if it works...

[6stringbassist]

[quote name='Weird War' post='362097' date='Dec 23 2008, 04:02 PM']I want to get RCD protection for gigs but need to travel light (as I'm on foot 90% of the time!) - would I be best getting a RCD socket rather than an extension lead or cable reel? Saw one in B&Q today for a tenner, looked a bit plastic but if it works...[/quote]

I have one of both, like you I like to travel light.

[Tinman]

[quote name='6stringbassist' post='362066' date='Dec 23 2008, 03:31 PM']A socket tester is only good if you know what you're looking at, and it won't tell you if the neutral and earth are reversed.[/quote]
[url="http://www.trueshopping.co.uk/product.php?utm_source=froogle&utm_medium=cost-per-click&pid=24246&cid=361&affid=25&utm_campaign=Sealey_13A_Socket_Tester_230V_14_Function"]http://www.trueshopping.co.uk/product.php?...30V_14_Function[/url]
I realise that this won't tell you that they're reversed but, it will tell you if there is a fault on either line.

[6stringbassist]

According to a friend of mine who's an electrical engineer, the most important thing with a circuit is the earth fault loop impedance.
If this is too high then whatever protective device you have at the fuse board, may not disconnect fast enough to protect you in the event of a fault.
A martindale or other socket tester won't tell you if the earth fault loop impedance is too high, and can give the user a false sense of security, the best thing is to just use an RCD at all times, the RCD won't work, ie let current flow, if there is a fault, and will protect you if one develops while you are playing.