Outdoor subpanel won't isolate ground and neutral

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fzzysprk

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Missouri
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Residential Electrician
Got a customer with an outdoor subpanel that feeds outdoor landscape loads and his dock on a lake. The electrical inspector says the entire sub panel must be GFI protected. Problem is that the soil conductivity is extremely high and even though the utility meter base where the neutral and earth ground are bonded together is over 120 ft away, there is still continuity between neutral ground all the way down at the outdoor sub panel. With all the wires in the conduit (2 Hots, a neutral and a ground) unhooked and isolated from each other there's no path to ground. But when the neutral up at the meter base gets landed on the neutral bus inside the meter base there is now continuity at the outdoor sub panel from the neutral to the ground rod at the sub panel. There is a separate breaker inside the meter-base that feeds power down to the outdoor sub-panel. 60 amp GFCI breaker that's inside the outdoor subpanel won't function properly, due to the neutral-earth ground short. Breakers are Eaton CH series. Is there anyway to isolate this sub-panel to make a GFCI work? The neutral bar inside the sub-panel is on plastic risers and does not connect to the ground bar. With the main #4 solid copper ground wire removed from the meter-base, there is still continuity from the meter-base Neutral buss bar and ground wire. PoCo came out and spent 2 hours to tell me "Guess its just really conductive dirt". 400 amp underground power feed.

Is there technology or a different method to get a 2 pole GFCI to work here? Or am I overlooking something?
 
fzzysprk said:
But when the neutral up at the meter base gets landed on the neutral bus inside the meter base there is now continuity at the outdoor sub panel from the neutral to the ground rod at the sub panel.
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Welcome to the forum.

Unless I misunderstand what you're saying, of course the neutral and grounding at the sub-panel will read as connected, because they are at the meter end.

If you disconnect the neutral at the meter end (feeder breaker off, of course), and disconnect all loads, the neutral should then read as floating, i.e., isolated.


The GFCI issue should have nothing to do with what sounds like a properly-wired sub-panel feeder. Do you know whether a non-GFCI breaker will hold?

It could be leakage current within the length of the feeder. I would try a regular breaker at the meter end, and a GFCI main breaker in the sub-panel.
 
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Prior arrangement at this sub panel was was regular breaker feeding from meter-base down 120 feet of 4 AWG to the sub-panel. Worked for unknown number of years, dock had individual GFCI protected receptacle devices on the dock. AHJ came around and inspected docks on their own volition and red-flagged the dock.
Inspector came out and re-inspected and passed the dock after I installed WR rated receptacles, and I had installed 2 single pole combo AFCI/GFCI breakers to control the dock lights and receptacles respectively. These breakers never tripped. Inspector called his boss after inspection and then decided the entire outdoor landscape devices also on the sub-panel needed to be protected with a GFCI main breaker controlling all power feeds. I installed a 60 amp GFCI 2 pole, (which was very hard to locate due to Eaton CH series) and then the problems started. I replaced the AFCI/GFCI breakers with regular breakers and installed the 60 amp GFCI breaker.

ETA: I am back-feeding the power thru the GFCI 60 amp breaker to the buss bars of the sub-panel.
 
With the banch breakers turned off in the subpanel does the GFCI at the main still trip ?
 
augie47 said:
With the banch breakers turned off in the subpanel does the GFCI at the main still trip ?
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wwhitney said:
I expect that's the problem--a GFCI breaker is not bidirectional, since it is monitoring the conductors connected to the top side lugs, and not the bus side lugs. You'll need a different solution to GFCI protect the panel.

Cheers, Wayne
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That was my fear, that the GFCI wasn't bi-directional. When I first installed the 60 amp GFCI I turned it on with all branches circuit off. Turned on 1 single pole breaker, no issue. Turned on the next 20 amp breaker and had a BOOM from the 60 Amp GFCI breaker, at the place where the pigtail comes out of the back of the breaker body, leaving black soot on the white pigtail. Oddly enough the 60 amp GFCI still provided power to the branch circuits, functioning as a normal breaker.
 
You could set a 60A "spa panel" box in which to terminate your feeder, and then have it supply a 60A backfed breaker in your existing panel.

Cheers, Wayne
 
This page is from another manufacturer, but I assume they will all be the same...all the QO GFCI and AFCI breakers cannot be...

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Just got off the phone with Eaton, he is looking into specifics on distance limitations if I can feed the dock sub panel from the meter base.

As to the 60 amp spa panel box, that is how it was set up prior with a non-GFCI breaker feeding the sub panel, but the inspector said it had to be eliminated and the sub-panel be the main disconnect point. The Fire Dept here is the AHJ, and it's a bozo show at times.

Obviously I will have to check every branch circuit in the sub panel in depth to make sure that there is no shorting between neutral, ground or hots.
 
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The panel its self does not require GFCI or GFPE protection unless it is located on the dock. If it is located at the bank, it is not on the dock, but supplied the dock. Only if the feeder is routed on the dock does 555.35 require protection. Otherwise the feeder and panel don't not, but the individual branch circuits will.
 
I really doubt the GFCI breaker is intended to be back fed, though I don't know why anything would go boom either just because it were back fed.

Another potential issue here is it being a 60 amp GFCI breaker. Not certain about what Eaton has, but I know 60 amp QO GFCI's are only available (or at least once were) with no neutral load terminal. The neutral pigtail on the breaker is only for supply to the internal electronics, if you supply a 120 volt load it will trip every time there is load and could not be used in the supply line to any 120 volt loads.
 
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