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Author Topic: Tripping GFI  (Read 20626 times)

Geoff Doane

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Re: Tripping GFI
« Reply #30 on: July 11, 2016, 03:37:06 PM »

Capacitors are used to correct for power factor -- when current and voltage do not align. So, when powering up some devices, is it possible that some capacitance (inductance?) or power factor issue is causing the current on the neutral to lag or lead the current on the hot? That would mean that while the RMS input/output current is the same, the waveform of the current is not aligned between the hot and the neutral. The GFCI senses this misalignment as an imbalance and trips.

The instantaneous current at any point of a series circuit  (think of the hot-load-neutral as a series circuit) will be the same at any given point in time.  The current can lead or lag the voltage (that's power factor), but if it's not leaking off somewhere (no longer a simple series circuit), then the hot=neutral as far as current is concerned.

I don't think GFCIs will trip on overcurrent anyway.  Just last week some contactors at my day job lost power from an outside outlet that they had a chop saw and bench saw plugged into.  The GFCI could not be reset, but I eventually was able to track down the circuit, and the 15A circuit breaker feeding the GCFI was tripped.  I suspect they tried to run both saws at the same time.  After resetting the breaker, all was fine again.

GTD
« Last Edit: July 11, 2016, 06:14:22 PM by Geoff Doane »
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Stephen Swaffer

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Re: Tripping GFI
« Reply #31 on: July 11, 2016, 05:17:24 PM »

Guy,

Thank you. Now you have my curiousity up.  I have wondered for years why GFCI breakers cost so much more than receptacles.  Perhaps this explains it.  I will have to see if I can locate trip curves on GFCI breakers maybe the extra cost does make sense.
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Steve Swaffer

Randall Cook

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Re: Tripping GFI
« Reply #32 on: September 07, 2022, 08:22:39 PM »

I've been having this same problem; tripping 20-amp GFI receptacles that my sub amps are on (nothing else on those circuits).  Happens when I try to push kick drum and sub drops where I need the levels to be... and sometimes just barely running the subs trips them.  If they're plugged into regular receptacles (non-GFI), I never have a problem.  I'm using K10's and set to 15-amps driving TH118XL subs.
Tops are KF650z run by PL325 (horn), PL380 (10"), and PL380 (15").  Those never trip GFI receptacles.

Everywhere we play outdoors I have to deal with this.  And we play A LOT of outdoor shows!
I understand the GFI is in place for safety, but come on.   This is ridiculous.  I doubt anyone would be hurt by me plugging my sub amps into a non-GFI receptacle.  Is this an American thing?  Sorry for my ignorance.  I need a real solution.  Thank you!
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Erik Jerde

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Re: Tripping GFI
« Reply #33 on: September 07, 2022, 10:56:44 PM »

I've been having this same problem; tripping 20-amp GFI receptacles that my sub amps are on (nothing else on those circuits).  Happens when I try to push kick drum and sub drops where I need the levels to be... and sometimes just barely running the subs trips them.  If they're plugged into regular receptacles (non-GFI), I never have a problem.  I'm using K10's and set to 15-amps driving TH118XL subs.
Tops are KF650z run by PL325 (horn), PL380 (10"), and PL380 (15").  Those never trip GFI receptacles.

Everywhere we play outdoors I have to deal with this.  And we play A LOT of outdoor shows!
I understand the GFI is in place for safety, but come on.   This is ridiculous.  I doubt anyone would be hurt by me plugging my sub amps into a non-GFI receptacle.  Is this an American thing?  Sorry for my ignorance.  I need a real solution.  Thank you!

The fact that you've got gear which doesn't trip GFI's is a good indication that your sub amps are the problem and are leaking current to ground.  You're probably 100% right that no one is going to get hurt from your amps.  Most of the electrical code though (especially GFI and AFI) comes from someone getting hurt/killed.  Unfortunately there's no way for the code to take in your specific situation and make an exception for you.  Have you talked to Powersoft and asked them what can be done to stop nuisance trips?  Maybe they know a GFI product that will work and then you can just provide your own.
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John Roberts {JR}

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Re: Tripping GFI
« Reply #34 on: September 08, 2022, 12:55:14 AM »

I've been having this same problem; tripping 20-amp GFI receptacles that my sub amps are on (nothing else on those circuits).  Happens when I try to push kick drum and sub drops where I need the levels to be... and sometimes just barely running the subs trips them.  If they're plugged into regular receptacles (non-GFI), I never have a problem.  I'm using K10's and set to 15-amps driving TH118XL subs.
Tops are KF650z run by PL325 (horn), PL380 (10"), and PL380 (15").  Those never trip GFI receptacles.

Everywhere we play outdoors I have to deal with this.  And we play A LOT of outdoor shows!
I understand the GFI is in place for safety, but come on.   This is ridiculous.  I doubt anyone would be hurt by me plugging my sub amps into a non-GFI receptacle.  Is this an American thing?  Sorry for my ignorance.  I need a real solution.  Thank you!
The GFCI protection trips when more than 6 mA or so of mains current leaks somewhere other than returning from whence it came.

Human safety is not ridiculous. 

JR
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Stephen Swaffer

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Re: Tripping GFI
« Reply #35 on: September 08, 2022, 09:02:03 AM »

I've been having this same problem; tripping 20-amp GFI receptacles that my sub amps are on (nothing else on those circuits).  Happens when I try to push kick drum and sub drops where I need the levels to be... and sometimes just barely running the subs trips them.  If they're plugged into regular receptacles (non-GFI), I never have a problem.  I'm using K10's and set to 15-amps driving TH118XL subs.
Tops are KF650z run by PL325 (horn), PL380 (10"), and PL380 (15").  Those never trip GFI receptacles.

Everywhere we play outdoors I have to deal with this.  And we play A LOT of outdoor shows!
I understand the GFI is in place for safety, but come on.   This is ridiculous.  I doubt anyone would be hurt by me plugging my sub amps into a non-GFI receptacle.  Is this an American thing?  Sorry for my ignorance.  I need a real solution.  Thank you!

15 amps vs 20 amps makes no difference to the GFCI.  As JR pointed out-GFCI's strictly care about the difference between the current on the hot and neutral leg-the actual current draw is irrelevant.  Can you borrow/rent another identical sub and try it?  Substitution is a powerful troubleshooting tool-and insisting that it can't be fill in the blank is a sure way to frustrate your search for the real problem.

Very few people actually do things that they think there is better than winning the lottery chance of someone getting hurt-but that doesn't stop people being injured or killed.  The longer I am involved in electrical work (counting by decades now) the more I understand rules I once thought silly.
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Steve Swaffer

Frank Koenig

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Re: Tripping GFI
« Reply #36 on: September 08, 2022, 11:19:49 AM »

I'm using K10's

For what itís worth, this is the exact model of amp that causes the same problem for me. When I try to measure the leakage itís essentially zero and the amps donít trip the GFCIs in my home. Maybe different GFCIs react differently to the fair bit of switching hash these amps put on the line. Perhaps a line filter of some sort is the answer. ĖFrank
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Steve-White

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Re: Tripping GFI
« Reply #37 on: September 08, 2022, 12:29:02 PM »

For what itís worth, this is the exact model of amp that causes the same problem for me. When I try to measure the leakage itís essentially zero and the amps donít trip the GFCIs in my home. Maybe different GFCIs react differently to the fair bit of switching hash these amps put on the line. Perhaps a line filter of some sort is the answer. ĖFrank
i was thinking along the lines of an isolation transformer between the GFCI & amps, but that would defeat the GFCI.  Putting an inline choke or filtering circuitry would be tricky to get something that worked, yet didn't induce significant voltage loss.

Maybe a balancing capacitor across the line at the amp?

Seems like something the manufacturer should address.  This comes from a Crown owner.  :)
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John Roberts {JR}

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Re: Tripping GFI
« Reply #38 on: September 08, 2022, 07:09:34 PM »

i was thinking along the lines of an isolation transformer between the GFCI & amps, but that would defeat the GFCI.  Putting an inline choke or filtering circuitry would be tricky to get something that worked, yet didn't induce significant voltage loss.

Maybe a balancing capacitor across the line at the amp?

Seems like something the manufacturer should address.  This comes from a Crown owner.  :)
I vaguely recall hearing stories about some of these early switching amps not being GFCI friendly.

An isolation transformer  will not make a difference the leak is from line-neutral loop to ground or elsewhere, but leaks to chassis ground is most likely candidate.

Indeed Crown should know... or maybe do a search?

JR
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Steve-White

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Re: Tripping GFI
« Reply #39 on: September 08, 2022, 08:11:51 PM »

I vaguely recall hearing stories about some of these early switching amps not being GFCI friendly.

An isolation transformer  will not make a difference the leak is from line-neutral loop to ground or elsewhere, but leaks to chassis ground is most likely candidate.

Indeed Crown should know... or maybe do a search?

JR

An isolation transformer between the GFCi and the amp absolutely would make a difference.  1) It would most likely correct the problem, 2) It would also invalidate the GFCI in the process.  :)

Bad idea.
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Re: Tripping GFI
¬ę Reply #39 on: September 08, 2022, 08:11:51 PM ¬Ľ


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