Testing for shock hazard

Gaylen James · Post by **Gaylen James** » 20 Jun 2020 3:31 pm

What would be the fastest, easiest way to test for potential shock hazard on a unfamiliar environment?
I've been blasted a couple times from bad, reversed or non existent grounds and I dont think much of it.
Walked up to the mic one night in Nevada and got thrown right into the drum set. I never play without a foam windscreen and sometimes I can still feel the current trying to get to me.
Any thoughts? Thanks in advance

Mike Auman · Post by **Mike Auman** » 20 Jun 2020 3:41 pm

These are pretty handy, for a start, and not expensive.

Gene Tani · Post by **Gene Tani** » 20 Jun 2020 4:40 pm

I've seen checklists including wearing shoes, never use ungrounded plug, correct fuses, outlet checkers etc here's a couple

https://www.guitar-repairs.co.uk/electr ... _stage.htm

http://www.singlecoil.com/docs/shock.pdf

Lee Baucum · Post by **Lee Baucum** » 20 Jun 2020 5:23 pm

Mike Auman wrote:These are pretty handy, for a start, and not expensive.

Agreed. We test all outlets prior to plugging in any equipment, at all venues ... even venues we play at regularly.

Gaylen James · Post by **Gaylen James** » 28 Jun 2020 6:19 pm

Let me try to make this a little more clear.
I have circuit testers and volt meters but not the knowledge.
How would you test for a shock hazard between a pa system and my bass? A concrete pad and my bass or steel?
What if we are out of phase with each other?
Just because something has a ground does not mean it is the same ground as another instrument.
Thoughts?

Georg Sørtun · Post by **Georg Sørtun** » 28 Jun 2020 8:06 pm

Unless someone has messed up wiring in some of your equipment, "CORRECT WIRING" shown on a proper mains-tester for ALL outlets used by your equipment should mean "you're perfectly safe".

If you want/need to feel safer than that, you will have to measure for voltage between GROUNDS/SHIELDINGS on all your equipment when it is connected and turned ON. There should be no (zero) voltage measured between GROUNDS, or shieldings on input-signal cables, from one piece of your equipment to another, or else you have a problem.

Dom Franco · Post by **Dom Franco** » 28 Jun 2020 9:05 pm

I used to always get shocked on the lips when singing and playing electric guitar (steel too) Years ago most amps only had two prong power plugs and the blades were both the same size so you could easily reverse polarity and get zapped.

I soon learned to touch the mic to the guitar strings and check for sparks before sacrificing my lips.

Then I bought a multi-meter (at radio shack) and tested for AC voltage between the PA system (microphone) and my guitar amp (Strings) It was 110VAC! when the plugs were reversed.
Later some better amps had a ground switch or 3 prong plug.

Now with more modern equipment I haven't been shocked for a long time.

Dom Franco · Post by **Dom Franco** » 28 Jun 2020 9:06 pm

I used to always get shocked on the lips when singing and playing electric guitar (steel too) Years ago most amps only had two prong power plugs and the blades were both the same size so you could easily reverse polarity and get zapped.

I soon learned to touch the mic to the guitar strings and check for sparks before sacrificing my lips.

Then I bought a multi-meter (at radio shack) and tested for AC voltage between the PA system (microphone) and my guitar amp (Strings) It was 110VAC! when the plugs were reversed.
Later some better amps had a ground switch or 3 prong plug.

Now with more modern equipment I haven't been shocked for a long time.

What would be the fastest, easiest way to test for potential shock hazard on a unfamiliar environment?

touch the mic to the guitar strings and check for sparks

Godfrey Arthur · Post by **Godfrey Arthur** » 29 Jun 2020 3:56 am

This might be a safer solution.

6 ft. 12/3 GFCI Adapter Extension Cord

Bill A. Moore · Post by **Bill A. Moore** » 29 Jun 2020 6:43 am

Test the circuit!
Many of the venues in my part of the country were originally wired in the 30's 40's, and the upgrade to 3 prong was always questionable. When I started playing, (drummer), my job was to flip the 2 prong plugs around, so everybody's mic was correct to their amp.
Back in the 80's I was diligent about getting all the amps into correct wiring. (I even had a reverse wired jumper for the venues that had the hot/neutral crossed). We all plugged into a 10 gauge extension so everybody was safe! One venue in Clifton, I had found a correct wired socket, and set the PA up, but our lead singer had plugged her amp into the wall! Before I realized she was in a reverse wired socket, she stepped to her mic for a sound check, and got bit! I straightened things out, but it was late in the second set she was singing like she meant it!

Post by **Dave Mudgett** » 29 Jun 2020 7:49 am

The first reply is, IMO, is always important. Get a circuit tester, test every outlet you wanna plugged into, and if it isn't right, don't use it. If you can't find a correctly wired outlet, the place needs to be rewired so that at least one outlet/circuit is correct.

Back in the 80's I was diligent about getting all the amps into correct wiring. (I even had a reverse wired jumper for the venues that had the hot/neutral crossed). We all plugged into a 10 gauge extension so everybody was safe!

Good idea. I try to get our bands to all plug into the same circuit. Sometimes it isn't logistically convenient, but that is the best approach - not only from power perspective, but also a ground loop perspective. If it's not a real loud gig, I plug my Furman Voltage Regulator into a known, good circuit and we run extensions from that. But it is only good for 12-15 amps, not enough for a high volume/power situation.

6 ft. 12/3 GFCI Adapter Extension Cord

I've used heavy duty ground fault interrupters. Sometimes it works, other times it hasn't due to dirty power tripping the GFI. Never had a problem when run after my Furman, however. In fact, if you're sure your power is clean, I think it's a good idea to use some of these as extra insurance if a problem occurs. For example, if a high-voltage amp cap shorts to ground, you have hot voltage at chassis. But I would not use this as a subsitute for properly wired power circuits.

When a club does its own sound, it frequently has the PA in a different location, running on a totally separate circuit. It's also important to know that that circuit is also wired correctly. I have very occasionally (I think twice) run into problems where the stage was wired correctly and mics were still shocking us because the PA wasn't! The mic snake was coming from the FOH setup. Moral: always, always check to make sure mics aren't shocking you before you grab one hard, regardless of how much care you take setting up.

Dave Grafe · Post by **Dave Grafe** » 6 Jul 2020 6:51 am

All the best advice has been given already, I will only add that the quick and painless way to check for ground potential is to turn up the guitar and touch the mic to the guitar's strings or tuning keys. If there is any voltage present at all you will hear a noticeable "pop" on contact, and if so you will want to at the very least put a foam windscreen on the mic, and be aware of the potential for a sting. If you have time follow the suggestions above.

The higher the voltage the more aggressive the noise will sound, and if you can SEE the spark jump between mic and tuning gear something is entirely wrong and MUST be addressed toot sweet.