Electrical box question

[kadoka]

A question for you electricians out there. I have my temp electrical box on the pole with a GFC outlet on it. I have my house wired (not everything hooked up) but have not yet run the underground SE cable. I had an idea that I could hook up a extention cord to my main panel in the house and power and test circuits as I hooked them up. It blows the breaker on the temp panel. It is not that important that I do this but I am curious as to why this is happening. I thought maybe the polarity of the extension cord was wrong but the polarity checks out fine. This happens with all breakers including the main breaker turned off so it can't be anything with the wiring in the house. Any insight would be appreciated.

[Sparks]

Where are you attaching the cord at the house panel? You said it happens with everything turned off, something must be grounded or shorted somewhere. Get you meter out and check for a grounded hot or a short, can't be an overcurrent issue since everything is off.

[kadoka]

Sparks, Nothing is shorted. Checked it with a meter. Yes the panel is in the house and the source is the temp box on the meter pole. The house box has a ground rod attached to it and the temp box has a separate ground rod attached to it. I am attaching the cord to the main power lugs coming into the box with the main breaker turned off. It has to be something weird with the ground.

[Sparks]

You said it is blowing the breaker? Is it a gfci breaker? Or is it just tripping the gfci receptacle? If it's tripping the gfci either breaker or receptacle, this is normal. If you're hooking up the hot from the cord to 1 phase lug, and the neutral to the neutral lug, and the ground to the ground lug, this will trip the gfci everytime because your neutral in your main panel is bonded to the ground creating an imbalance current in relation to the hot. If you just hooked a cord directly to a non-gfci breaker and brought the hot to one phase lug in main, the neutral to the neutral lug in main and the ground to the ground lug in main, the non-gfci breaker should not trip. If you intentionally ground a neutral wire coming from a gfci breaker or receptacle, it will trip, even with everything off. Again, if you're just talking about a normal non-gfci breaker that is tripping, there is something wrong somewhere and the redundant ground rods should have nothing to do with it. If it is the gfci tripping, breaker or receptacle, you could just temporarily remove the green bonding screw or strap at the house panel and hook up as suggested, then it should not trip.

[Vector]

Are you running 120V or 240 from the temp to the new?

[Sparks]

My response was based on the assumption it was 120v since he mentioned the gfci receptacle and extension cord.

[Vector]

Me too, but you know what happens when you assume...

[kadoka]

Sparks,

You are correct. I am hooking it to a GFI outlet on the temp panel at the pole. I figured it was something like that but just didn't understand what was happening. I appreciate the explaination.

Kadoka