Open Ground question

[DBECHEN]

Hi all, I have been having a problem with plugging into the shore power at our storage facility. They have all circuits run through GFCI outlets on the pole. When we plug in and we are not running anything the GFCI trips on the pole. We talked to our storage facility manager and they had an electrician come out and he said the issue was our RV having an open ground. We have a Progressive Industries surge protector that was installed by the first owner. When we plug into the 30 amp plug at our house and in campgrounds there is no problem. Any ideas what may be causing this? Thanks in advance.

[Hank_MI]

drsteve wrote:
I built a garage six years ago, and under code here in MI everything had to be protected by GFCI, including inside outlets, outside outlets, the dedicated air compressor circuit, and the door openers. The only exception was the lighting circuits.

Pretty sure that was just your local inspector and not MI code. I've dealt with them before and you'll get different answers from different inspectors. You need to ask them to see the code. MI pretty much follows NEC, of course your local community may have different codes. GFCIs are not required where I live, Livingston County.

[myredracer]

ktmrfs wrote:
One warning, a GFI will NOT prevent all possible electrocution hazards. For example if I have on rubber soled shoes on dry surface and get across the hot and neutral with both arms, good chance the GFI won't trip. In this case there likely would not be enough leakage current to a ground to cause an imbalance.

I recall when GFCIs first came out in the 60s I saw a demo on TV where someone held onto a live wire that was connected to one of the newly developed GFCI receptacles and jumped into a pool. He didn't float back to the surface... Could be dreaming or have early-onset dementia tho. Maybe they could try that on Mythbusters and see what happens. 🙂

[drsteve]

I built a garage six years ago, and under code here in MI everything had to be protected by GFCI, including inside outlets, outside outlets, the dedicated air compressor circuit, and the door openers. The only exception was the lighting circuits.

[ktmrfs]

enblethen wrote:
disposal and dishwasher are a fixed appliance and normally on dedicated circuit. They should be hardwired to house wiring.

current code requires them to be on dedicated circuits, but not necessarily hardwired. In my case the instahot, disposal and dw are required to be on seperate circuits. but only the DW is hardwired. instahot and disposal each have their own circuit and individual outlet. and these are not required to be on a GFI. GFI is required for the accesible kitchen outlets.

but lets get back on track helping the OP figure out why his trailer is popping a GFI.

[enblethen]

There is criteria that must be meant to use a cord. Some jurisdictions do not allow cords.
I preferr to have them hardwired.

[wnjj]

SaltiDawg wrote:

enblethen wrote:
disposal and dishwasher are a fixed appliance and normally on dedicated circuit. They should be hardwired to house wiring.

Like this one??? Garbage Disposal

Or this one??? Dishwasher

The real answer is they’re plugged into receptacles that aren’t easily accessible to be used for other purposes so there’s little chance of a human completing the circuit.

[SaltiDawg]

enblethen wrote:
disposal and dishwasher are a fixed appliance and normally on dedicated circuit. They should be hardwired to house wiring.

Like this one??? Garbage Disposal

Or this one??? Dishwasher

[enblethen]

Many motors on refers and washers have a capacitor to help them start. Weak or bad capacitors can cause tripping.

[CA_Traveler]

enblethen wrote:
disposal and dishwasher are a fixed appliance and normally on dedicated circuit. They should be hardwired to house wiring.

Mine are on dedicated circuits but not hardwired and not required by 2006 code.

[enblethen]

disposal and dishwasher are a fixed appliance and normally on dedicated circuit. They should be hardwired to house wiring.

[CA_Traveler]

My home refer is not on a GFCI. The plug is also not easily accessible for normal kitchen equipment.

But why isn't the disposal and DW on a GFCI?

[ktmrfs]

CA Traveler wrote:
OK if motors etc cause a GFCI to trip then they would be an impossible nightmare on 30A and 50A RV plugs.

Yikes - Yes my bathroom and kitchen counter top plugs are GFCI protected.

Sorry I just spaced out when thinking about one of my GFCI circuits. It has 8 garage and outside plugs with 270' of 14 gauge wire on a 15A CB. Not knowing this my saw wouldn't cut hot butter on the last plug. All wired to NEC and county code as I found out.

and if the fridge is on one of kitchen circuits, I'll bet they wired it so fridge is outlet 1 and a GFCI outlet on outlet 2.


In reality the likelyhood of a ac motor tripping a GFCI is remote for a properly functioning motor but it does exist. Especially in locations with open frame motors that can collect lots of dust, dirt, oil etc. the reason for the NEC exception is that a false trip on a fridge or freezer has pretty signficant consequences. so NEC doesn't require them to be on a GFCI when other items are. Seems like a reasonable exception.

personally in 35 years I have never had a motor trip a GFCI, and that includes my trailer AC, and all the other motor devices in the house and workshop, including some pretty high HP motors and pretty old motors.

But I sure wouldn't want to come home from vacation with a fridge or freezer that tripped a GFCI.

[wnjj]

road-runner wrote:
A motor that trips a correctly working GFCI has a real ground fault. I'm guessing the refrigerator exception is there because some fridges do have ground faults and there was tremendous public and political pressure for the exception. Personally, I've had 2 refrigerators and a freezer on GFCI circuits continuously for 9 years with zero trips. I run the RV including the heat pump, air compressors, and an irrigation pump with no GFCI trips. The only trips I have had are from making some mistake when making a temporary connection or with using test equipment (like forgetting that one side of the scope probe is earth grounded).

I had a small chest freezer trip the garage GFCI twice over a period of a couple of years. After the 2nd time, I rewired the plug away from the GCFI.

[road-runner]

A motor that trips a correctly working GFCI has a real ground fault. I'm guessing the refrigerator exception is there because some fridges do have ground faults and there was tremendous public and political pressure for the exception. Personally, I've had 2 refrigerators and a freezer on GFCI circuits continuously for 9 years with zero trips. I run the RV including the heat pump, air compressors, and an irrigation pump with no GFCI trips. The only trips I have had are from making some mistake when making a temporary connection or with using test equipment (like forgetting that one side of the scope probe is earth grounded).