Tripping GFCI Breakers New Install

[williamsmithaud]

I need a little help with this one guys. Here's the situation: I just installed a two breaker disconnect box and seperate ground rod at the sea wall between my lake house and my boat dock. The disconnect box has separate ground and common terminal bars and the common bar is insulated from the metal of the box. There is an existing 3 W/G line from the house supplying two 120V circuits to the new disconnect panel's two buses, the common wire goes to the common bus bar and the ground wire to the ground bus bar. The Ground bar is also Grounded to the metal on the dock and to the new ground rod. The two 20A GFCI breakers are installed with their fixed white "panel common" attached to the common bar. (NOTE: The intent of the previous home owner was to have two separate 120V circuits on the dock, not to have 240V)

The two load wires from the dock are of course connected to each breaker's load side respectively. The "load common" connectors are tied to the one common wire going out to the dock. With this wiring in place both of the breakers trip immediately when turned on. I know there is no ground fault on the load side because I replaced that wiring.

What follows may trigger a thought from one of you guys. I can disconnect the load common from one of the breakers and the other breaker will work perfectly. If I do this with the other breaker that the opposit one will also work. If i touch the two load common wires together both breakers will trip.

I'm beginning to think that this problem may be related to a phase issue at the house panel. I haven't pulled the panel cover yet but the two breakers are one on top of the other so they are probably on different phases. Does anyone think this is the problem? If so I can simply move the house breakers around and sove it.

As always, I will appreciate any help I can get on this.

 

[Dennis Alwon]

Is this a DP GFCI breaker with the neutrals from 2 circuits tied to the one neutral terminal?

 

[wirebender]

If you only have one grounded conductor (common) going to the dock from the panel with the GFCI breakers, that is the problem. They cannot share the grounded conductor (common).

 

[George Stolz]

I am closing this thread, in accordance with the Forum rules. This Forum is intended to assist professional electricians, inspectors, engineers, and other members of the electrical industry in the performance of their job-related tasks. However, if you are not an electrician or an electrical contractor, then we are not permitted to help you perform your own electrical installation work.


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