Tripping a GCFI outlet

[RJ]

Have any of you experienced tripping a 15 amp gfci outlet on the power pole (or house outlet) when plugging your bus into shore power using an adapter from your 30 or 50 amp umbilical cord?

I have, and my theory (which may not be accurate!) is based on my automatic transfer switch's default setting being the genset.  I believe this is because of the ground/neutral bonding difference between being on the genset or being hooked to shore power.

When I plug into a gfci outlet, the gfci senses that the default ground/neutral bond of the transfer switch in genset mode "isn't right" and instantly trips.

Am I even close here, or is this delusional suffering from too many Pepsis?

TIA,

RJ

[Gary Hatt - Publisher BCM]

RJ,  Ask Dick Wright tomorrow when you see him at the Florence, OR rally.  Or call him as he should be able to guide you in the "Wright" direction.  :-)

[Geoff]

Yes, I have had that happen.  I go from a 50amp cord to a 30amp cord to a 15-20amp house plug and it trips the house breaker.  So my backup is my permantly mounted 40amp 3-stage charger and it won't trip the GFI using a regular extension cord.

[neoneddy]

Yup, that's about how it is. I was bummed out when I paid $10 to park at a lot in Duluth and they had 15a service with GFI outlets. Tripped Everytime. Luckily we were making enough solar to run the AC for the pooch.

[akroyaleagle]

When that happened to me, it turned out to be one half a stray volt in the inverter.
One wire was switched and the problem went away and has not returned for over 22 years.

Please  don't ask which wire, I have slept since then.

[silversport]

I installed a relay on the power pole line before the Progress Industry box, when plugged into a power pole the relay separates the bond in the electrical box before the PI lets the power thru.   

[bevans6]

While the problem might be the ground neutral bond, I have my doubts.  GFCI works just fine without ground at all, it simply detects a difference in current flow between the live and neutral circuits.  It's probably detecting a difference as your ATS decides to switch to it's secondary  source, maybe due to timing of the relays or imperfect current flow through the relays.  My ATS is set up for power cord primary, and it doesn't trip GFCI's (so far).

[richard5933]

If the problem tripping the GFI is the ATS bringing the neutral/ground bond forward from your genset there is a simple way to test this.

Disconnect the generator neutral from the ATS and tape it up. See if you still trip the GFI.

[thomasinnv]

The ats should be wired so that shore power is the primary source, meaning that when shore power is applied there is no switching required in the device. Generator should be secondary, switching takes place when the generator is running. Some people get confused here, because the generator "takes" priority when it is running but is actually the secondary device. If your ats is wired in reverse it WILL cause gfci to trip when the relays try to engage. I have had a hand full of customers with the same issue and have always been resolved by correcting the ats wiring.

As a side note, the generator neutral/ground bond should be at the generator not at the ats. Every electrical supply needs to be bonded at it's source.