ECN Forum Forums General Topics of the Trade General Discussion Area main breaker tripping

Hi Guys

Without getting into why some things are done the way they are done in Bosnia here, I will ask my question.
I recently had a service call for a power failure. I went to the location and inside the building was a sub panel fed off a main panel just outside. The fault was unknown but was causing the main breaker to trip outside. Over here they use a G.F.I. breaker in alot of cases and this was the breaker that was tripping. It is very common over here to find local tradesmen tying neutral to ground in a device or receptacle. This causs alot of problems for me but anyways. Now the fact that they tied neutral and ground and the G.F.I. breaker triped is not hard for me to see, but as a test I took the G.F.I breaker out and replaced it with a normal breaker to see if it would still happen and it did.After this I went inside and spent many hours taking things apart and found in two cases where neutral and grond where tied together and seperated them. Things seem to be good now.My question is finally! Once the G.F.I breaker was replaced with a normal one , with all the load in the building turned off, the main breaker was still tripping,the neutral and ground were still tied together in some of the juntion boxes I found at this point. Is it a backfeed that is traveling up the neutral from the main panel that is causing this? Can someone help me SEE THE LIGHT ! I am just not quite sure . I hope I explained myself well enough.
Thanks

Greg Smith
Camp Black Bear
Bosnia

Greg,
What is the service(volts,phases,amps, # of wires)?
Chris

Depending on the type of GFI (two, three or four wire) and the type of service it might have nothing to do with the incorrect neutral to ground bonds. Tell us more.

Thanks for the reply guys:

The service is a single phase, 220 volt 30 amp, 50 Hz two wire ,feeding some sleeping accomodations.I think you are right about the GFI Ron, because as I had said in the first email when I took the GFI breaker out of the loop and put in a normal breaker it still tripped. I got through last night without getting a service call so
I think I am in the safe zone. I am just curious about why when I seperated the grounding and neutral everything was good. I tried drawing it out so that it made sense but it stil doesnt.
Later
Greg Smith
Camp Black Bear
Bosnia