Amplifier Safety - Anyone using GFCIs?

[balance]

**mods, feel free to move this to the Lounge if it is not appropriate here. Since it is safety related, I thought a broader audience would be better**

Hi,

I've been playing guitar/bass for a number of years now, often singing at the same time. I've played a lot of venues with very questionable power, and have used my share of questionable gear. We've all heard stories of lethal shocks in these situations; God knows I've been shocked more than once - none lethal yet though.

Is there anyone out there using GFCIs to protect themselves? Are they recommended? You can buy commercial power strips with GFCIs built in. Alternatively, it would be pretty easy to build an extension cord with a GFCI receptacle in a box.

Any comments?

Brian

[Mick Bailey]

I've always used one - you cannot guarantee what the wiring is like in a venue. Years ago these were really expensive, so I used a commercial single-socket GFCI and plugged my power strip into that.

One thing to watch; Every appliance has some earth leakage - if you connect too many items to a single GFCI the cumulative earth leakage value can exceed the trip threshold and keep on nuisance tripping. This is especially the case with vintage valve amps. The answer if you have this problem is to use a couple of GFCIs

[drewl]

I use a wireless which has the added advantage of isolating me from my amp.
I believe my rack power strip has a protection circuit in it, can tell if there's a bad ground as well as filter emi and rf interference.

[earthtonesaudio]

I used to use a power strip that had lights to tell you when the outlet was good or faulty.  But recently I upgraded to a 4-outlet GFCI box on a 2 meter cord.  I'll still probably use an outlet tester if I have the chance, but having everything powered with the GFCI box is very reassuring. 

Right now I'm using it in my friend's damp basement and we have 2 solid state amps (sometimes 3), and all our effects plugged into it.  So far no nuisance reset.

Recommended? YES!

One bit of advice, don't make assumptions where safety is concerned.  Just because something can tell you if there's a grounding problem, doesn't mean it protects you from lethal currents.

[R.G.]

GFCIs are not the be-all and end-all of protection.  Here's an interesting question: If you put your GFCI box before your gear and it keeps tripping, do you have the presence of mind (and self preservation) to tell the bar owner that you're not playing and walk out if he can't provide you safe power?   

That gets right to the heart of the question: are you willing to die for your music? 

I've spent a number of my columns in Musician's Hotline, now Premier Guitar, on the issue of AC power safety. They're all available on line and provide some good reading for people who want to live for their music.

First: if YOUR amps leak AC, like most old two wire amps do, and some three wire amps, it's YOUR responsibility to get that fixed. If you don't, you're setting a trap for yourself or anyone who plays with you. Make sure all of your equipment is properly three-wire safety grounded.

Next: practice safe AC. Go to a hardware/home improvement store and get an outlet tester. This under-$10 device will tell you flat out if the AC outlet you plug into is wired correctly or backwards and if it has a good safety ground. Put one of these in your gig bag and test the outlets before you use them. There are incompetent electricians around, too.

Next: Use your meter. You have a DMM if you read here. Set it to 200Vac and see how much voltage there is between the microphone and your guitar strings, the bass player's strings, other mikes, etc. If you get over a few volts AC, there's a shock hazard there.

There's a lot more, but just using a GFCI won't help all that much, other than making an intolerable number of nuisance trips.

[Morocotopo]

For the benefit of those of us that are not North Americans, could you explain what is a GFCI, so that we can find something similar in our countries?

Morocotopo

[R.G.]

Ground Fault Current Interruptor

The third (safety) wire from the AC line socket to the equipment is not supposed to have ANY current traveling through it. Zero. None. 0.0000ma. If there is any current in the safety ground, that means that current in the two main power lines is unbalanced, and that current is coming in on one of them and going back out by some means other than the other power wire. This "some means other" could be a human being. That being the case, the GFCI opens the power to both line and neutral, presumably quickly enough to save the human's life.

There are several means of detecting a ground fault. One is to look for current in the safety ground wire, the other is to look for perfectly balanced current in both AC power wires. An unbalance in the currents has the same meaning as safety ground current - AC power is leaking out somewhere and not just going into the device and back out.

[JFX09]

this link might be of interest, it explains how to install a GFCI


http://www.rona.ca/content/installing-gfci-ground-fault-circuit-interruptor-outlet_electricity_plumbing-electrical_renovation-construction

[Morocotopo]

Thanks R.G. for the explanation, that seems like a rrrreally nice thing to have for personal safety!!! I´ll investigate something like it in my country.

Morocotopo

[slacker]

I think in other countries they're called residual current devices or RCDs.

[Mick Bailey]

Anyone thought of using an isolation transformer? The sort used on building sites etc. Don't know if you get them outside of Europe - most of our supplies are 230v - 240v. That DOES give you a bite.

[R.G.]

Yep. That's part of what's in the "lots more" in my articles on electrical safety.

Isolators are good, and do prevent the building's electrical problems from being visited on you. They are also ...heavy... which means that most people will not use them.

An isolating regulating transformer is even better.