GFCI Distance Too Far?

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kwired said:
Not a joke. A capacitor is two metal plates with insulating material between them, you have capacitance between conductors in a cable or raceway, but is such a poor capacitor it normally isn't something we take much consideration of. Make those conductors a hundred, two hundred feet long, it starts to become enough capacitance to matter when you consider the low current trip level of a GFCI. Now fill the raceway with water, and depending on the purity of the water can make an even better capacitor out of it.
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I had no idea. Awesome to know and I am sure it will come handy when I troubleshoot.:thumbsup::thumbsup:

hbiss said:
A surge suppressor after a GFCI breaker will guarantee nuisance tripping of the breaker.

-Hal
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Explain please how this works, especially with the clamping voltage mentioned by Kwired.
 
Bring an extension cord , power the pump up if it runs it's the power ran to the pump. Ohm out the underground wires, if that checks out move to the gfci breaker..

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Jraef said:
Cable capacitance would have been a problem from day one, unless as mentioned, there has now been a water intrusion..
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Is that the same capacitance shown as voltage by high-impedance volt-meters when power is off, vs low impedance solenoid or Wiggy meters?
 
Receptacle-connected pool pumps shall be GFCI protected since 2002, hardwired since 2008, NEC 680.21/22

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Originally Posted by Jraef
Cable capacitance would have been a problem from day one..

When do GFCI's have trouble with wire-length capacitance? Not found in GFCI listing, or instruction.
 
ramsy said:
Receptacle-connected pool pumps shall be GFCI protected since 2002, hardwired since 2008, NEC 680.21/22

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Originally Posted by Jraef
Cable capacitance would have been a problem from day one..

When do GFCI's have trouble with wire-length capacitance? Not found in GFCI listing, or instruction.
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Every install has different characteristics that will impact this. But long circuit lengths will have more troubles as a general rule then short circuit lengths. 100 feet maybe fine load side of a GFCI, but 150 or 200 and you may see more tripping for no apparent reason but is possibly capacitive leakage current. All depends on how good of a capacitor ends up being developed in how things lay out.


Is that the same capacitance shown as voltage by high-impedance volt-meters when power is off, vs low impedance solenoid or Wiggy meters?
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Most of the time that is capacitively coupled by an adjacent circuit that is energized.
 
badbanano said:
Run #10 and put a dedicated twist lock plug on a normal breaker.

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680.21(C) GFCI Protection:


Outlets supplying pool pump motors connected to single-phase, 120-volt through 240-volt branch circuits, whether by receptacle or by direct connection, shall be provided with ground-fault circuit-interrupter protection for personnel.
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GFCI protection would still be required, even if it were direct wired.
 
JFletcher said:
No, the code only requires GFCI protection or not.

Imo, it's better to protect with a breaker at the source than with a receptacle since the branch circuit conductors are protected in their entirety.
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GFCI is for protecting people, the conductors don't need GFCI protection, just short circuit, ground fault, and overload protection is all the conductors need.

That said the longer the circuit the more subject it is to capacitive leakage and non intended tripping of a GFCI if it is at the beginning of the circuit.
 
kwired said:
GFCI is for protecting people, the conductors don't need GFCI protection, just short circuit, ground fault, and overload protection is all the conductors need.

That said the longer the circuit the more subject it is to capacitive leakage and non intended tripping of a GFCI if it is at the beginning of the circuit.
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Quite true however if one were to cause a fault upstream of a GFCI receptacle, or come into contact with bare conductors, say from rodent damage, poor installation or whatever reason, they wouldn't be protected against shock whereas they would with a GFCI breaker.

At what distance do GFCI devices become a problem? Surely there are installations with 200' of wire on the load side of a GFCI receptacle, or 200' of wire from a breaker, and they work. Is there a hard limit of distance in the instructions?

eta: Apparently SqD GFI breakers are for 250' or less:

http://www.schneider-electric.us/en/faqs/FA117270/
 
JFletcher said:
Quite true however if one were to cause a fault upstream of a GFCI receptacle, or come into contact with bare conductors, say from rodent damage, poor installation or whatever reason, they wouldn't be protected against shock whereas they would with a GFCI breaker.

At what distance do GFCI devices become a problem? Surely there are installations with 200' of wire on the load side of a GFCI receptacle, or 200' of wire from a breaker, and they work. Is there a hard limit of distance in the instructions?

eta: Apparently SqD GFI breakers are for 250' or less:

http://www.schneider-electric.us/en/faqs/FA117270/
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Every circuit is going to have it's own differences. Rodent damage, poor installation, etc. can happen even when GFCI protection isn't required.

When GFCI protection is required the intent is to protect the user. Voltage on an EGC will still be a shock hazard to the user even when there is GFCI protection, which is sometimes what happens when there is problems at a marina or dock even when there is GFCI protection.
 
Capacitive leakage is real

Capacitive leakage is real

I had thought I recalled the 250' figure for length as was quoted for SQ-D. Thanks.

When ever there is a GFCI issue it seems so rare that anyone actually measures the leakage current.

I converted the coil used in a GFCI outlet to a cheap circuit to measure leakage current. Because I am cheap. I believe differential leakage meters are around $300 or more?

Christmas lights are a great example. My father in-law puts up too many strings. Eventually the leakage gets high enough - then add a rain & pop.
We installed 4 separate GFCI outlets to "divide up the leakage".

I used my cheapo leakage meter and could watch the leakage raise over a minute or so from 3,4, 5, 6 ma and then not too long after a trip occurred.
 
Old thread up in a previous life I worked in a coal mine as head of electrical. Power supplies for communication and personal tracking were strict on spacing and didn't always line up with where we had power set up. Typically you had a source of 120 every mile but the communication power supplies would hit in the middle some times. To cut in a 12470v to 120v power skid would run about $100,000 so we ran some long 120 runs. 10/3 soow cords would sometimes be finicky to get set up but once set up they were fine. The load was only 750ma on the power supply so we were within 5% even in the middle. Under 1000' I can't recall having issues but when you would go above that it would sometimes. It also didn't matter if the power supply was plugged in or not. Just the cord would trip the gfci.
 
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