ECN Forum Forums General Topics of the Trade General Discussion Area A puzzel for Henry C

Neutral connection between the main panel and the sub panel was open?

Did the GFCI stop its peculiar behavior when the main breaker feeding the sub panel was opened?

Larry C

Neutral and ground tied together by mistake at the load at the pool? Coupled with a weak neutral connection at the meter or such place going to the POCO, (or bad neutral in the sub-panel, and another circuit in the subpanel is drawing current) and some neutral current wanting to get back to the POCO's transformer's neutral finds a path thru the GFCI's neutral, to get to that ground by mistake? MIght not need a bad neutral, Just some normal neutral current being diverted to the mistaken ground connection (more than 7 or so ma of several amps would do it).

This had everyone stumped for two days. POCO was called to check the house. Everything was fine. They also checked the neighbors house and found an open neutral.
The neighbors house, 200 feet away, was sending enough voltage through the earth to the new inground pool, with rebar and steel mesh in the apron, to be picked up by the GFI receptacle.
The older GFIs would trip on an imbalance between the black and white as well as anything on the ground.
It was the only time I ever saw a GFI trip when it had no power going to it.

Open neutral... I'm having a hard time envisioning an open neutral that would cause ground current. Unless you mean that the poco's neutral line to the house was broken, and all the neutral current was flowing through the neighbor's ground rod to the ground rod by the pole? Well, not counting the current flowing through your pool ground

Nice puzzle!

Neutral was open at the weatherhead on the house.
Ground rod and water bond as well as the earth to the swimming pool were the only return pathes. They worked well enough that the house wasn't experiencing an unbalance between the phases.