Killer Gig - How to avoid electrocution on stage.

[zac2944]

I had a bad experience last weekend at an outdoor gig where the guitar player and I were shocked pretty good during sound check as soon as we checked our mics. No one was seriously hurt, but from what I've dug up here and elsewhere online the potential for death was there.

The gig did go on after the sound man "fixed" the issue, but I refused to sing. I have an engineering background and understood the lethal potential that was there, and I've heard stories about people getting shocked really bad. The other singers gave in to the pressure to perform and trusted that the gear was now safe.

This episode, and the fact that I'm playing another outdoor music festival this weekend, lead me to dig into this issue a little deeper. I found some good threads here on this topic:

Shocked through strings - how to correct?

Being shocked?

Not getting shocked

A really good idea

I also found a guitard website with great info on avoiding electrocution on stage:

Shock Hazards

I though putting all this info in one place and sparking some new discussion might help others learn how to protect themselves on the gig. I won't go into the technical explanation of why it happens, the Shock Hazards link above does a great job of that. Here's a few things I learned that you can do to better protect yourself:

1. Using a wireless system for your bass and a wireless mic can disconnect you from any faulty power and eliminate most common shock scenarios.

2. Test all outlets with a checker (<$10 at hardware store) and even try to test the outlets that the PA is plugged into.

3. Hold out your bass so that the strings touch the mic. Don't allow your body to be part of the electrical path. If you see sparks, you've got problems. Might hurt your gear, but could save your life.

4. Outdoor gigs with generator power are notorious for shocking hazards. If there is an issue in a club that books a lot of bands, chances are the problem will be found and fixed. At an outdoor gig, you might be the one to "find" the problem. Also, not all outdoor gigs are wired by a professional electrician.

There is a lot of other great info in the threads and article posted above, but these items were new info to me and make a lot of sense.

A few question to leave you all with:

1. How many of you are testing outlets already? Has a club or soundman given you any trouble for asking to do this?

2.What do you do if you find a fault? Refuse to play? What if your outlet checker gives you a fault, but no one is getting shocked? How do you interpret the data?

3. Have you personally known someone who has been seriously hurt by a shock on stage? I've heard stories, but nothing I can confirm.

[T-Bird]

Hi.

Glad to hear that You're still among us, a shock like that can be fatal.

Originally Posted by zac2944

A few question to leave you all with:

1. How many of you are testing outlets already? Has a club or soundman given you any trouble for asking to do this?

2.What do you do if you find a fault? Refuse to play? What if your outlet checker gives you a fault, but no one is getting shocked? How do you interpret the data?

3. Have you personally known someone who has been seriously hurt by a shock on stage? I've heard stories, but nothing I can confirm.

1. I don't. Over here it's nearly impossible to find a faulty outlet.

2. If I suspect a fault (generator for example), I test the leakage and rectify it before playing.

3. Not on stage, but back in the day I got a mild shock on a rehearsal. DIY was the emphazised word .

Regards
Sam

[PJSShearer]

There was a similar thread a week or so ago on this. In the UK we use a gadget call an RCB that trips a circuit breaker if a leak to ground is detected - you plug them into the outlet before you plug in your extension lead. These are fitted to home domestic fuse boxes by default these days here but I still use an additional one when I use the electric lawn mower - in case I run over the cable.

I nearly got killed when I was 14 when my amp was grounded, my friend's wasn't and we swapped guitars - my hands and arms were locked by the DC voltage running through me, but I managed to throw myself backwards to try and get away. As I hit the ground, the singer pulled one of the guitars off me, thank god.

These days I listen for that tell-tale 50Hz hum and any clicks and thumps coming out of the PA - just in case!!.

[ggunn]

Originally Posted by PJSShearer

I nearly got killed when I was 14 when my amp was grounded, my friend's wasn't and we swapped guitars - my hands and arms were locked by the DC voltage running through me, but I managed to throw myself backwards to try and get away. As I hit the ground, the singer pulled one of the guitars off me, thank god.

I'm glad you survived, but it wasn't DC voltage.

[Dirk Diggler]

A simple yet elegant solution, bring your own windscreen, or even better your own mic and foam windscreen. Another benefit is it also keeps you from chipping your teeth too. I know a singer that a drunken person came up to talk to him, knocked the mic right into his teeth which he lost 2.
And yes always test your outlets, you'd be amazed at how bad and inconsistent venues can be. A cheap tester can be had for under $10, it will show ground faults and out of phase wiring.
Dirk

[PJSShearer]

Originally Posted by ggunn

I'm glad you survived, but it wasn't DC voltage.

I was told it was at the time, and my body definitely reacted differently to a normal 240v AC shock that I'd had a few of before and since!! - in those cases the muscle spasm threw my hand(s) open. In this case ny fingers were locked - I couldn't let go of my Bass or my friend's Guitar. If you can point me at some releveant reading? as I am a nerd at heart (I work in IT now) I'd like the full technical skinny (yes I am that sad)!!.

[zac2944]

Originally Posted by PJSShearer

In the UK we use a gadget call an RCB that trips a circuit breaker if a leak to ground is detected - you plug them into the outlet before you plug in your extension lead.

Here we call that a Ground Fault Circuit Interrupter (GFCI). I just bought a nice one tonight at the hardware store along with an outlet tester. Here you also see GFCI on kitchen and bathroom outlets. They have little buttons that say "test" and "reset". What they do is monitor current in vs. current out, if there is a big enough difference (because current is going through you!) the GFCI interrupts the circuit. It takes a frection of a second (25/1000), and you will still get a shock, but it can keep you from getting killed.

[Bard2dbone]

Originally Posted by Dirk Diggler

A simple yet elegant solution, bring your own windscreen, or even better your own mic and foam windscreen. Another benefit is it also keeps you from chipping your teeth too. I know a singer that a drunken person came up to talk to him, knocked the mic right into his teeth which he lost 2.
And yes always test your outlets, you'd be amazed at how bad and inconsistent venues can be. A cheap tester can be had for under $10, it will show ground faults and out of phase wiring.
Dirk

Good call. Mic socks aren't conductive. No contact between you and metal = no electocution.

Way back in the day, my guitarist would leave the extra length of his strings trailing off of his headstock. His amp and mine were differently grounded. I had a ground switch and he didn't. This one time, switch had been moved. I found out when he turned around and his strings touched my arm.

[BurningSkies]

I test the outlet before plugging.

If you're outside, make sure you're not playing on bare earth or concrete. We spec a dance floor or raised platform for outdoor shows.

We also carry some of those area mat/rugs that are rubberized on the bottom and carpeted on top. I set up my rig on the edge of the carpet and stand on it through the set and it isolates me from concrete or bare ground...

[PJSShearer]

Originally Posted by zac2944

Here we call that a Ground Fault Circuit Interrupter (GFCI). I just bought a nice one tonight at the hardware store along with an outlet tester. Here you also see GFCI on kitchen and bathroom outlets. They have little buttons that say "test" and "reset". What they do is monitor current in vs. current out, if there is a big enough difference (because current is going through you!) the GFCI interrupts the circuit. It takes a frection of a second (25/1000), and you will still get a shock, but it can keep you from getting killed.

Sounds like he same thing 2 me..

[zac2944]

Originally Posted by Bard2dbone

Good call. Mic socks aren't conductive. No contact between you and metal = no electocution.

True, but sounds like a bit of a band-aid. Could get a spark to jump the gap if you got close enough? Also the chassie of the mic could shock you.

[ZoomBoy]

Originally Posted by zac2944

True, but sounds like a bit of a band-aid. Could get a spark to jump the gap if you got close enough? Also the chassie of the mic could shock you.

I use a foam cover thing on my mic and have never had an issue but I test the outlets whenever I gig with one of those inexpensive testers especially when we are bringing our own PA with us. But you are right the potential for injury/death is there. Kinda makes me think of that scene in Almost Famous when the guy grabs the mic to sing and goes down.

[Bard2dbone]

I've been shocked by bare mics when I touched my lip to them a couple of times. Both of those times I was holding the mic and only got shocked when it touched my lip. So I doubt that the mic chassis is much of a problem.

But touching the screen while playing an instrument is a much higher level of electricity. Now you've gone from annoying to possibly lethal. It's good to check your circuits. But use a mic sock as well.

[PJSShearer]

Originally Posted by PJSShearer

There was a similar thread a week or so ago on this. In the UK we use a gadget call an RCB that trips a circuit breaker if a leak to ground is detected - you plug them into the outlet before you plug in your extension lead. These are fitted to home domestic fuse boxes by default these days here but I still use an additional one when I use the electric lawn mower - in case I run over the cable.

I nearly got killed when I was 14 when my amp was grounded, my friend's wasn't and we swapped guitars - my hands and arms were locked by the DC voltage running through me, but I managed to throw myself backwards to try and get away. As I hit the ground, the singer pulled one of the guitars off me, thank god.

These days I listen for that tell-tale 50Hz hum and any clicks and thumps coming out of the PA - just in case!!.

I've just read this (which is actually mentioned in the first post in this thread DOH!!!):

http://www.guitarnuts.com/technical/...fety/index.php

.. and Scenario 1 is what happened to me. I strongly recommend reading it from top to bottom.

On a lighter note, I was told by a friend of mine that at the old Vickers Aircraft Factory in Weybridge they would "bait" the apprentices by holding a live cable in one hand and then saying "Pass me that screwdriver, would you?". Beats sending them to the stores for a "long weight" (wait) or "Tartan paint" ... :-).

[ggunn]

Originally Posted by PJSShearer

I was told it was at the time, and my body definitely reacted differently to a normal 240v AC shock that I'd had a few of before and since!! - in those cases the muscle spasm threw my hand(s) open. In this case ny fingers were locked - I couldn't let go of my Bass or my friend's Guitar. If you can point me at some releveant reading? as I am a nerd at heart (I work in IT now) I'd like the full technical skinny (yes I am that sad)!!.

The only DC in your amp is in the tube supply circuits and there is no way for it to get to the amp chassis unless something is dreadfully wrong with the amp. Even then it would blow a fuse right when you turned it on. Shocks from grounding issues with amps and PA gear are AC.

[PJSShearer]

Originally Posted by ggunn

The only DC in your amp is in the tube supply circuits and there is no way for it to get to the amp chassis unless something is dreadfully wrong with the amp. Even then it would blow a fuse right when you turned it on. Shocks from grounding issues with amps and PA gear are AC.

I quote from the document I linked to:

There are three shock scenarios the guitarist faces. These scenarios are not "theoretical," musicians have died!

1. Failure of the guitarist's own amplifier places a lethal voltage on the "ground" side of the jack and thus on the strings. This scenario is usually only encountered on early vintage equipment. Even then such failures are extremely rare but when they occur they can place hundreds of volts DC on the "ground" side of the jack and the failure may be difficult to detect until the shock knocks you on your backside. This failure is basically impossible with modern three-prong equipment plugged into a properly grounded three-prong mains outlet. Never use ground lift adaptors on power cords! The shock path is from the amplifer, through the guitar chord to the guitar bridge and strings, to the guitarist's fingers. From there the shock path either goes through the guitarist to the floor through his feet or through the guitarist to a grounded piece of equipment such as a microphone. Even the first path through the resistance of shoes and floor covering may sometimes be lethal because the voltage potential is so high. The second path is easily lethal because the path from the guitarist to earth ground has very little resistance to the flow of current.

This happened in 1972 with gear that was 10+ years old.