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Old 08-21-2007, 06:41 PM   #1
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Default Spa Sub Panel Keeps popping GFI Breaker

We hooked up a Spa for a customer of ours.

60 amp breaker with a 60 amp GFI subpanel. Subpanel keeps popping the breaker.

We replaced the breaker 3 times, Cutler Hammer. Customer had the spa replaced, and the problem still exists.

We have noticed that when the plasma TV turns on the subpanel will pop.

Any ideas?

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Old 08-21-2007, 09:12 PM   #2
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What size wire did you run?

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Old 08-21-2007, 09:39 PM   #3
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A) Why did you replace the breaker three times? Did you expect something different after the first replacement? Didn't you test the breaker to see if it holds with no load and the neutral tail connected?

B) What does the wire size have to do with it?




Does a regular breaker hold? If so then you do have a true ground fault.
Find this fault and you've solved the tripping breaker.
- Bad wire somewhere?
- Hidden ground/neutral touching somewhere?
- Neutral wire nicked and grounding out?
- Miswire?????
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Old 08-21-2007, 10:27 PM   #4
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Since he's replaced everything else, why not replace that plasma TV and send the bad one over to my house.

Just for research purposes of course....



In all honesty, my keen troubleshootng mind says the problem is with the TV.
Does it have a 3 prong plug?
If so try one of those "cheaters" that used to be so common, thusly removing the ground wire from the equation.
If it still pops the gfi then you have a miswired receptacle.
If the gfi holds then the TV is the culprit.

Or just use a good meter to the prongs of the TV plug.
I don't have my calculator out here on the porch, but you get ohms less than 120/0.005 between ground prong and neutral prong then send the TV back.
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Old 08-22-2007, 08:16 AM   #5
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The breaker was replaced the first time just because. The third time it was replaced because the spa manufacturer said it "had"to be the breaker. The wiring between the subpanel and the spa was replaced twice just because, size #8. Distance between the spa and subpanel is roughly 5 feet.

Since we are at lost with what the problem is the breaker was replaced, what would you do? Especially since it was been rewired four time, by three different people to see if we were missing something, and then the spa was replaced, same problem.

We will pursue the TV avenue.

Thank-you!
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Old 08-22-2007, 10:03 AM   #6
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Customer called this morning and said when the microwave was used this morning she heard the breaker pop.
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Old 08-22-2007, 11:11 AM   #7
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Is this equipment that's popping that breaker on that breaker's load side? If so, I think it's time to start meggerring some stuff. If that stuff that's causing it to trip isn't even served by that breaker, it might be time to phone CH technical support.
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Old 08-22-2007, 12:13 PM   #8
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Are these all different breakers in the same panel? Check the conditions of the busbars on the panel. You might have a damaged panel that is in need of immediate attention.
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Old 08-22-2007, 02:13 PM   #9
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Well, we are going to pop the meter and start checking to see if the neutral and ground has tight connections all the way to the subpanel and spa.

If all is well, maybe there is a loose neutral at the utility pole?!
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Old 08-22-2007, 02:16 PM   #10
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The spa doesn't pop the GFI breaker which is on the load side. The GFI breaker pops from other appliance/equipment on different breakers.

The GFI popping is also intermittant. It doesn't always pop when the TV is turned on or other appliances.
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Old 08-22-2007, 03:07 PM   #11
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SO... none of this stuff that trips the GFCI is actually on it's load side? That's as strange as they come. I know that RF (like from a 2-way radio) will trip a GFCI. Other than that, I don't even have a guess as to what might be happening in your case. I'd probably still megger the load side out, just in case you're getting bad information. They may just be associating what they happened to be doing at the time as the cause of the GFCI tripping, when it really had nothing to do with it.
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Old 08-22-2007, 05:44 PM   #12
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while the meter is pulled, also pull the main bonding jumper and check continuity between neutral and ground, or just shut off the main and check continuity before they come pull the meter
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Old 08-22-2007, 09:41 PM   #13
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Yeah sounds like harmonic's from the electronic equipment. As you said before, check all the neutral connections and the ground connections. Only other possible solution would be to up size your neutral to help lower the harmonics.
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Old 08-31-2007, 09:41 AM   #14
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Well,

All ground and neutral connections are tight, from the spa sub panel to the meter.

We are going to replace the cutler hammer subpanel with a square D. Not for any reason other then we prefer square D. The main panel is square D so atleast all will be the same, QO series.

This is very strange.
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Old 09-08-2007, 07:18 PM   #15
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The customer had run the wire from the subpanel to the main panel to cut down on installation costs.

We traced this wire and found that there was a 3' loop of wire looping back upon itself, if that makes sense. We straightened out the wire so it wasn't looping. The spa has stayed on without popping the breaker now for 5 days.

Could this loop have been causing some freaky thing with the GFI popping?
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Old 09-08-2007, 07:30 PM   #16
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Quote:
ZachYeah sounds like harmonic's from the electronic equipment.
BALONEY, BALONEY, BALONEY yeah and lets drive 20-10 foot ground rods BALONEY to the harmonics especially in a single phase distribution system.

As for the loop it is quite possible you set up an induction coil which MAY cause GFCI issues, basically this could work like a single winding transformer.
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Old 09-08-2007, 08:31 PM   #17
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I'm no engineer, but sounds very plausible that the accidental induction coil could have screwed with the CT's in the GFI.

I hope this home owner paid well for his stupidity, why would he want to store the extra wire in his walls?
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Old 09-08-2007, 08:42 PM   #18
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Default Some thoughts on harmonics

BY NO MEANS IS THIS MET TO BE A DEFINITIVE ANSWER TO HAMONICS, I put this together off the cuff. There are numerous books available on this subject and the web can be a wealth of some good and SOME BAD information regarding harmonics.

JUST SOME BASIC THOUGHTS


Harmonics are a result of distorted current waveforms that result in distortion of the voltage waveform, often harmonics are refered to as POLLUTION of the electrical distribution system. In my experience the issue with harmonics is way overblown and everything from the magic bullet in Dallas to the fall of the Berlin Wall has been blamed unjustly on harmonics. Harmonics can be a real problem and I have been involved in several projects with harmonic issues, but these are few and far between and lessen as the industry adapts to minimize the effects of harmonics.

With harmonics there are several different issues, the first is with single phase harmonics on 3-phase distribution systems.

Harmonics as we commonly refer to them in the electrical industry has to do with switchmode power supplies and the way these power supplies draw current only at the peak of the sine wave, resulting in distortion of the voltage sine wave and what is resulting triplen harmonics or 3, 6 9 13, 15 ect these current harmonics do not cancel in 3-phase systems on the neutral instead they are additive in a 3-phase system. These distortions result in neutral current in excessive the normally expected neutral current, this current can overload branch circuit and feeder neutrals and result in excessive heating of transformers. With single phase transformers these load currents are not additive in the neutral and therefore are not an issue. In early harmonic rich distribution systems single phase transformers were utilized to overcome the additive current issue. Now excessive load current with high percentage of THD (Total Harmonic Distortion) can result in voltage distortion, though this is unusual epically from the low percentage of electronic loads in a residence. Where this could be an issue is on a residential generator as the system impedance is so much lower than the utility.


There are other items that result in harmonics these are also typically found in 3-phase distribution system, these harmonics are from 6 and 12 pulse converters these result in 5/7, 11/13, 17/19….with the 6 pulse converters and 11/13, 23/25, 35/37 harmonics with 12 pulse rectifiers. Once again these require a high level of current distortion before this current distortion will affect the voltage sine wave, this level changes when the site is placed on generator.

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Old 09-08-2007, 08:56 PM   #19
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So what you're trying to say is that the high speed switching in my 802.11b router is not what's causing my bathroom GFI to trip.
The router draws 10mA which means it must be sending 10A back on my neutral system, right?
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Old 09-09-2007, 11:34 AM   #20
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In a single phase residential or 3 phase distribution system using 2-wire branch circuits (hot/ungrounded conductor, neutral/grounded conductor and equipment grounding conductor) if you have 10 amps load on the ungrounded conductor and the circuit is wired per the NEC then you have 10 amps on the neutral.

Same situation but with a 3-phase multi-wire circuit, 3 ungrounded conductors and a single neutral, with a pure resistive load with 10 amps on each phase the neutral current is "0" (Zero). If the load is a harmonic rich load (comprised of equipment with switch mode power supplies), theoretically the neutral current can be as much as 2 times the expected current (this number may be a bit off as I am pulling it off the top of my head, I will verify on Monday), in field I have seem 1.3 times.

Where this has been an issue typically has been data centers, casinos and call centers, most office buildings I have worked in have light loads on the branch circuits, and usually do not overload transformers beyond 30% by desing and use.

That’s not to say leakage current does not result in tripping GFCI’s. But with new decent/good insulation leakage is minimized. There are limitations on the length of conductors in regard to leakage as the longer the conductor run coupled with higher amperage loads the more leakage current. Worse case that I have seen was with receptacles ran to a sewage injector pit the contractor utilized panel mounted GFCI’s #10 awg about 150’ plug in any load 5 or so amps and above GFCI tripped. This was direct burial cabl,e I do not remember the megger readings but the readings were in the acceptable range. The solution was to mount the GFCI at the pump location.
further reading

http://www.usace.army.mil/publicatio...m5-689/c-5.pdf

http://www.copper.org/applications/e...pq/issues.html


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