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Author Topic: GFCI advice please  (Read 11462 times)

Curt Sorensen

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GFCI advice please
« on: May 26, 2015, 06:06:25 pm »

Hi.
I'd like to offer some advice to a friend regarding an installation, but I'm not able to be as helpful as they deserve. Our State Capitol is replacing the electrical  distribution system on the grounds around the Capitol building. The current plan is to have all GFCI outlets. This would be the only power available to sound and lighting systems [or whatever] short of a generator. I warned them of the issues that some equipment has with GFCIs. Can anyone point to information regarding the issues, and how the industry is working within the Code to provide professionals the power they need while protecting the general public? Something that might help bureaucrats, architects, engineers, and committee members, etc who aren't going to grok the Code book.
It's been a long time since I looked, but I think they currently distribute power to a number of locations using L21-30 connectors, and events have to make arrangements to pick up adaptors that breakout to Edison. I can get more specific if needed, but for now I just want to help someone present the issues with some equipment running on GFCIs so they can work towards a proper solution.
Thanks all,
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Curt Sorensen
Madison, Wisconsin

Tim McCulloch

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Re: GFCI advice please
« Reply #1 on: May 26, 2015, 06:16:30 pm »

Hi.
I'd like to offer some advice to a friend regarding an installation, but I'm not able to be as helpful as they deserve. Our State Capitol is replacing the electrical  distribution system on the grounds around the Capitol building. The current plan is to have all GFCI outlets. This would be the only power available to sound and lighting systems [or whatever] short of a generator. I warned them of the issues that some equipment has with GFCIs. Can anyone point to information regarding the issues, and how the industry is working within the Code to provide professionals the power they need while protecting the general public? Something that might help bureaucrats, architects, engineers, and committee members, etc who aren't going to grok the Code book.
It's been a long time since I looked, but I think they currently distribute power to a number of locations using L21-30 connectors, and events have to make arrangements to pick up adaptors that breakout to Edison. I can get more specific if needed, but for now I just want to help someone present the issues with some equipment running on GFCIs so they can work towards a proper solution.
Thanks all,

All you can eat and more than you'll want to digest:  http://forums.prosoundweb.com/index.php/topic,154557.0.html

There is another thread regarding GFCI in the same forum.
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"Practicing an art, no matter how well or badly, is a way to make your soul grow, for heaven's sake. Sing in the shower. Dance to the radio. Tell stories. Write a poem to a friend, even a lousy poem. Do it as well as you possible can. You will get an enormous reward. You will have created something."  - Kurt Vonnegut

Curt Sorensen

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Re: GFCI advice please
« Reply #2 on: May 27, 2015, 03:17:00 pm »

All you can eat and more than you'll want to digest:  http://forums.prosoundweb.com/index.php/topic,154557.0.html

There is another thread regarding GFCI in the same forum.

Not at all more than I want to digest, it's very helpful. If I get it, GFCIs are needed pretty much everywhere in the latest code. So I think I've made an assumption that some [audio] gear does not play well with GFCIs, am I wrong about that? The other thread [I think] you refer to suggests that MOV-based surge protection is one likely culprit. Perhaps my first question should have been, if you showed up for an event and all that were available were GFCI Edison connections [possibly no larger than 30 Amp], would that be a problem?
Thanks,
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Curt Sorensen
Madison, Wisconsin

duane massey

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Re: GFCI advice please
« Reply #3 on: May 27, 2015, 09:00:46 pm »

If the sound company is set up to use individual circuits rather than a distro I don't see a problem. They should be prepared for the existing power availability, or they should bring a generator.
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Duane Massey
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TJ (Tom) Cornish

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Re: GFCI advice please
« Reply #4 on: May 27, 2015, 10:55:41 pm »

Not at all more than I want to digest, it's very helpful. If I get it, GFCIs are needed pretty much everywhere in the latest code. So I think I've made an assumption that some [audio] gear does not play well with GFCIs, am I wrong about that? The other thread [I think] you refer to suggests that MOV-based surge protection is one likely culprit. Perhaps my first question should have been, if you showed up for an event and all that were available were GFCI Edison connections [possibly no larger than 30 Amp], would that be a problem?
Thanks,
Three of my distros (range plug size) are all GFCI, and I have no false trips.  I have had two legitimate trips which are inconvenient, but a good thing.  I agree with Duane that anyone setup to use Edison circuits for power should be fine. 

A good compromise may be to do all GFCI Edison outlets (you're not going to be able to fight this anyway - outdoor circuits need to be GFCI), but get them to install a 400A (or 200A) 3-phase company switch that stays padlocked until used by authorized personnel.
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Curt Sorensen

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Re: GFCI advice please
« Reply #5 on: May 27, 2015, 11:13:46 pm »

If the sound company is set up to use individual circuits rather than a distro I don't see a problem. They should be prepared for the existing power availability, or they should bring a generator.

Yes, but are there audio devices that on power-up or in normal operation, dump enough current to ground that a GFCI will trip? I have been under the impression that there are. Many years ago I believe I had this problem with a Soundcraft Venue, but maybe something else was happening. Maybe I've been believing something that isn't so. I know I'm not the only one who's had this thought, and I don't want to perpetuate a misunderstanding. In the thread Tim linked to, I understand it to say that you won't satisfy the code unless every termination in a 'zone' is GFCI protected. That thread also clearly states that preventing public access to non-GFCI outlets is no longer acceptable [like using twist-lock connections as I've read on this forum some time ago].

NOTE: TJs response [which came while I was writing this] is more in the direction I was looking for, and thanks for that. I'm starting to wonder if 'false trips' may be similar to an audible ground loop, that they are fair warning that something is indeed wrong. I'd still like to know if my original belief is wrong, that is that some gear, in good repair, will create problems when used with GFCIs.

Thanks,
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Curt Sorensen
Madison, Wisconsin

Tim McCulloch

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Re: GFCI advice please
« Reply #6 on: May 27, 2015, 11:19:30 pm »

Three of my distros (range plug size) are all GFCI, and I have no false trips.  I have had two legitimate trips which are inconvenient, but a good thing.  I agree with Duane that anyone setup to use Edison circuits for power should be fine. 

A good compromise may be to do all GFCI Edison outlets (you're not going to be able to fight this anyway - outdoor circuits need to be GFCI), but get them to install a 400A (or 200A) 3-phase company switch that stays padlocked until used by authorized personnel.

And if you read Guy Holt's very thorough post in the Grounding and Electrical forum, you'll see that these higher-amperage circuits also need GFCI protection under the most recent revision of the NEC.  The good news is that these GFCIs are not intended to trip at 5ma (many are adjustable).

One of my gigs is a temporary setup in a common area.  The client drops a construction-type spider box.  Our gear typically doesn't trip the GFCIs, but band-provided extension cords, power strips, and guitar/bass rigs do...
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"Practicing an art, no matter how well or badly, is a way to make your soul grow, for heaven's sake. Sing in the shower. Dance to the radio. Tell stories. Write a poem to a friend, even a lousy poem. Do it as well as you possible can. You will get an enormous reward. You will have created something."  - Kurt Vonnegut

Mark Cadwallader

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Re: GFCI advice please
« Reply #7 on: May 28, 2015, 12:01:32 am »

Not at all more than I want to digest, it's very helpful. If I get it, GFCIs are needed pretty much everywhere in the latest code. So I think I've made an assumption that some [audio] gear does not play well with GFCIs, am I wrong about that? The other thread [I think] you refer to suggests that MOV-based surge protection is one likely culprit. Perhaps my first question should have been, if you showed up for an event and all that were available were GFCI Edison connections [possibly no larger than 30 Amp], would that be a problem?
Thanks,

By Edison circuit, I assume that to mean that the "outlets" are NEMA 5-15R or maybe a 5-20R (sometimes also referred to as a "U" ground outlet). A NEMA 5-30R is not something that the ordinary member of the public can plug in to. Someone better informed than I on the details of the NEC should chime in whether anything other than a 5-15R or 5-20R is "accessible by the public" and therefore something for which GFCI protection is required.
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Stephen Swaffer

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Re: GFCI advice please
« Reply #8 on: May 28, 2015, 01:10:27 am »

I would expect architects and engineers to refer to and be familiar with the code book-since that is their job.   Code generally requires all outdoor receptacles "supplied by 125 volt, 15 or 20 amp circuits"-with no discussion of the type of receptacle.  Art 525 modifies that requirement-but it requires not only receptacles but equipment accessible to the public to be GFCI protected.

The general attitude taken is that the receptacles need protection, period.  Compatability with gear is not an exception to the rule-the expectation is to bring the gear up to the standard not the standard down to the gear.
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Steve Swaffer

Tim McCulloch

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Re: GFCI advice please
« Reply #9 on: May 28, 2015, 01:16:32 am »

By Edison circuit, I assume that to mean that the "outlets" are NEMA 5-15R or maybe a 5-20R (sometimes also referred to as a "U" ground outlet). A NEMA 5-30R is not something that the ordinary member of the public can plug in to. Someone better informed than I on the details of the NEC should chime in whether anything other than a 5-15R or 5-20R is "accessible by the public" and therefore something for which GFCI protection is required.

The magic words used to be "...for use by personnel."  My local inspector said that was any outlet a non-electrician could walk up and plug a "common appliance" into.  NEMA 5-15 and 5-20 for sure, locking connectors like L14-20 or L21-30, no.

Based on what Guy discussed I get the impression that in some jurisdictions, "cord and plug connected equipment" will be considered "used by personnel" and require protection.
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"Practicing an art, no matter how well or badly, is a way to make your soul grow, for heaven's sake. Sing in the shower. Dance to the radio. Tell stories. Write a poem to a friend, even a lousy poem. Do it as well as you possible can. You will get an enormous reward. You will have created something."  - Kurt Vonnegut

ProSoundWeb Community

Re: GFCI advice please
« Reply #9 on: May 28, 2015, 01:16:32 am »


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