electric shock prevention?

[morbe]

Where was that awesome article on the many things that you could do to prevent electrical shock? I thought there was some threads here that talked about it. where they removed? It finally happened to me, I got Kissed by my Mic while playing the guitar. Not like a massive electric shock but more like static electric shock, but it just never went away. LOL. I remember reading something where is said to go wireless to separate my self from the electric circuit. I was able to resolve the shock by looking over the power connections etc. I found that the PA was plugged into an old Power strip that looked like every outlet had something explode in it! and that was plugged into another power strip that didnt look any better, then plugged into the wall outlet! I said WTF! I demanded that the PA be plugged directly into the socket. And the issue went away. I did try a new vocal pedal but I dont think that was the issue.
But now i have purchased a Wireless Guitar Rig I got from CL but I dont remember what the "SAFE" way was. was it wireless guitar and wireless mic? or just either wireless mic and wireless guitar? maybe it wasnt a forum thread but I do remember reading something like that here.
Thanks

[morbe]

Thanks everyone, I guess I posted too soon. I found what I was looking for shortly after posting the thread. I was talking with someone at a music store and he said those shocks from the mic are not dangerous because most equipment now a days are made three prong, "Famous Last Words" I thought. So I guess checking for outlet faults with a tester and going wireless on the guitar I should be fine. Or because I sing I should separate my mic from the electric lines by going wireless there also?

[newey]

Going wireless on either the mic or the guitar will solve the cross-amping problem. But for full safety with a tube amp set-up, wireless for the guitar is the way to go.

Not many tube PAs being used anymore, and the risk of a dead short with SS gear is minimal. So, with the mic, the only real worry is the cross-amping with the guitar amp. But if you use a tube guitar amp, there is a small risk of catastrophic failure which a wireless system will completely eliminate.

I was talking with someone at a music store and he said those shocks from the mic are not dangerous because most equipment now a days are made three prong,

You were right to question this "wisdom". The shock comes from two amps being cross-polarized. Back in the days of two-pronged plugs, this was a common problem. The three-pronged plug should solve the problem, but only if all the outlets in question are wired appropriately, extension cords are appropriate, etc- as you found out!

The shock is the same with or without a three-pronged plug- and it's still enough to injure or kill someone, given the wrong set of circumstances (Bad heart, wet socks on concrete floor, etc.)

[morbe]

Thanks Newey, I already got a guitar wireless system. The guitar wireless system I got I kind of rushed into since the incident, Its fair it does what it does with no drop outs. My only issue is Im still setting it up after a few weeks. though only I can tell it tends to make my peavey delta blues amp sound like a solid state amp, but from what I'm reading is that the I have adjusting to do with squelch, rf signal, etc.
Im looking more into Wireless mics and want to get a decent one, but having a hard time deciding what to get. I do know I want to get a "UHF" since digital is out of my price range. but even the high dollar systems have mixed reviews. My budget is only about $250 which I know is not much but for my level of musical commitment (jam sessions, very small gigs) I thinks its pretty decent. any suggestions?

[morbe]

I just checked my equipment with a simple test. I first made sure that the Ground Prong on both the PA and my Amp have continuity to the Chassis and they both do. I also made sure that the other two prongs did NOT have continuity to the chassis and they don't. The other two prongs also did not have continuity to each other. Is this a decent test to double check the that my equipment is working and wired correctly? Is there a way to plug the amp in and check readings with a multimeter to make sure that high voltages are not bleeding over to the ground? LOL am I just freaking out here? LOL I'm sure that the outlets are good I tested them a few months back with a tester. I've been asking myself, "How could the questionable power strips cause a shock?" I would love to take my tester and test those power strips. I wonder would it work the same and I wonder if it will give me a missing ground reading? I think Ive asked this before but could a 9 volt vocal pedal cause electric shock? The simple 9 volt power adapter is not grounded. and the particular pedal I have has phantom power on no matter what, no way to turn it off. The pedal didnt cause the shock obviously why are guitar and vocal effects that are plugged into a high voltage amp not grounded?

[newey]

Is there a way to plug the amp in and check readings with a multimeter to make sure that high voltages are not bleeding over to the ground?

That's a poor use for your multimeter, as well as being potentially dangerous to you. DO NOT try this at home!

You don't need a multimeter to test for that. That's called a "dead short". If it were happening, your amp wouldn't work, there would be lots of smoke and a burning smell, and in a second or so, your mains breaker should trip, turning off the power to that entire circuit.

Hopefully, the breaker trips before any damage to you, should you be touching any metal on your non-wireless equipped guitar.

I've been asking myself, "How could the questionable power strips cause a shock?"

If you had gotten a full 120VAC (presuming you were in North America) through the mic, I'd say the two amps were cross-polarized. But if it was just a small tingle, a bad ground could cause that.

You said:

WTF! I demanded that the PA be plugged directly into the socket. And the issue went away. I did try a new vocal pedal but I dont think that was the issue.

Thereby indicating that a faulty power strip (or strips) were the source of the problem.

I think Ive asked this before but could a 9 volt vocal pedal cause electric shock? The simple 9 volt power adapter is not grounded. and the particular pedal I have has phantom power on no matter what, no way to turn it off.

9VDC can cause a shock, as you probably found out when you were a kid and touched a 9V battery to your tongue. (As an adult, this is not a recommended course of action, even 9V is potentially dangerous.)

The adapter doesn't have the grounding prong of a three-pronged plug, but that doesn't mean that it's not grounded. It is, through the neutral prong of your house AC.

Since this adapter is converting 120VAC house current to 9VDC, a separate grounding prong would be superfluous. The third prong is there as a failsafe ground for AC, but this device isn't putting out any AC to the end use anyway.

I don't know what your reference to phantom power means. Phantom power isn't 9V, it's either 12, 24 or 48VDC. When you say it "can't be turned off", are you plugging a mic into a powered XLR plug? Is it a mic requiring phantom power, or just a regular dynamic mic? (It shouldn't matter, but I suppose a fault in the phantom power wiring could cause a shock, theoretically)

The pedal didnt cause the shock obviously

Right, so why are you concerned about it?

[morbe]

The reference to the phantom power on the pedal means that the pedal supplies 48VDC. Some devices that come equipped with phantom power give you the option to turn the 48VDC on and off. This pedal however doesn't give you that option. 48VDC is constantly running though the mic.

Im not worried that it was the pedal that was causing the shock. I was just wondering why they dont come with 3 prongs but you set me straight on that, thanks.

I guess I'm just trying to prevent a potentially lethal situation.

But just one last question. When I purchased my amp (used) the power plug looks like it was cut off and replaced with a new end. The fellow I purchased it from claims that it was there when he purchased it used and didnt know why it was done. Now I have had this amp a couple of years now. When I sing I eat the mic and I've never been shocked in the past so Can I assume that the wires are not backwards on amp plug causing cross polarization in the amp it self? I really have been procrastinating on getting the power plug and cable replaced. Guess its about time.

Thanks Newey

[sumgai]

Jan 9, 2013 7:59:45 GMT -5 morbe said:

But just one last question. When I purchased my amp (used) the power plug looks like it was cut off and replaced with a new end. The fellow I purchased it from claims that it was there when he purchased it used and didnt know why it was done. Now I have had this amp a couple of years now. When I sing I eat the mic and I've never been shocked in the past so Can I assume that the wires are not backwards on amp plug causing cross polarization in the amp it self? I really have been procrastinating on getting the power plug and cable replaced. Guess its about time.

Regardless of your past experiences, I'd suspect this 'modified' power cord. It may have always been bad, or it may have simply gone bad for whatever reason, but if it's not entirely original, then it's suspect, period.

But rather than waste time guessing and monkeying around with it, here's what I'd do:

For years now, I've always done this to my own amps, and suggested it to owners bringing their equipment into my shop, as needed. Stated simply, I replace the entire cord with a new one, usually longer than the standard 6 or 8 feet, and always a heavier gauge.

In every case, the benefits are obvious:

a) Better durability - it's able to withstand being stepped on time and again, or pulled when it shouldn't've been, etc.

b) It cuts down on extension cords - I use at least 15 footers, but sometimes a customer will want a longer one.

c) It's about gauranteed to be wired correctly inside of the plug itself, so any errors will be in my workmanship, and of course that just doesn't happen. (Riiiiiight. )

d) It's relatively cheap - considering what a repair bill could cost you. Extension cords usually run well under a buck a foot for 16 gauge, maybe that much for 14 gauge.

All I do is bop on down the local hardware store and purchase an extension cord of the required length. Cut off the socket end, strip back the outer and inner coverings, and Presto, a ready-to-install power cord. Tin the exposed leads for quicker adhesion, triple-check to make sure I'm not about to mis-wire it, and Voila!, it's Miller time!

I make it sound simple because it is that simple. This will fix any possible source of 'errant' electricity, should the cord have been the culprit in the first place. But even if it wasn't/isn't, just having the peace of mind of knowing that it's factory-fresh goes a long ways toward getting a better night's sleep. And no one ever got fired for having a power cord that was too long, right? ;D

HTH


CAVEAT!

Almost forgot to say..... If your amp is a two-wire unit, then install the same kind of cord. Don't make the mistake of thinking you can make your amp 'safer' just because you're now going to have the Ground/third wire for connection to the chassis. There are good reasons for saying this, but rather than dive into a 4-hour lecture, let me just say that unless you're a highly trained technician yourself, then you need to take your amp to one such, and if possible, provide a schematic for the amp too. Otherwise.... well, let's just say that more than one amp has gone to the Big Vacuum Tube In The Sky due to adventurous mis-wiring of this sort.

Of course, if your amp is a three-wire unit, then have at it! ;D

HTHA





sumgai