Electronics wizards! How did this ever work?

[Rocket J Squirrel]

Yesterday we had a power outage that lasted about 1/2 hour. When power resumed, I checked the breakers for my house and pool to make sure they hadn't tripped when the power briefly flip-flopped.

One of the GFCI breakers in my pool load center (Pentair EasyTouch 8) had tripped and would not reset. The wiring in the downstream junction box looked fine. I opened up the EasyTouch panel to eyeball the breaker. What I found was that the panel neutral curly white wire from the breaker was wired to the ground bar with all the green wires! I moved the white wire to the neutral bar and then the circuit worked fine, as it had before yesterday.

The ET was installed in 2018 and I haven't messed with its internal wiring at all (except to move the pump power from relay load to line). The "electrician" who installed the Easy Touch was the pool builder's son and seemed inexperienced. But white and green are obviously different. How or why did that circuit ever work? Extra bonus points for explaining why it quit working and why moving the white wire fixed it perfectly.

 

[JamesW]

The ground wires go back to the breaker panel where the ground and neutral are connected.

So, the ground simply carried the current back to the neutral in the panel and then back to the neutral on the transformer secondary side.

The breaker GFCI works by having the hot and neutral from a load both go through a ring in the breaker that detects current.

Since the hot and neutral have current going in different directions, the current cancels out and the GFCI does not trip.

The load neutral connects to the breaker and the breaker neutral should connect to the neutral bar.

Connecting the breaker neutral to the ground bar probably resulted in some stray current, but most current should have traveled back to the breaker panel neutral as that's the best path back to the transformer secondary neutral.

 

[ajw22]

Was this a 120V CB or a 240V CB that was miswired? The white neutral on a 240V CB does not carry any electricity in normal operation. The white neutral is the return path for a 120V CB.

A GFCI CB will not reset if it does not have a good neutral connection. I would check the ground in your electrical system as it may have opened if the GFCI would not reset with the neutral connected to the ground.

 

[Rocket J Squirrel]

It's a 120v breaker. Where would you put the probes to check ground?

 

[ajw22]

How far away is your ET from the main house panel it connects to?

I would first do a visual inspection and see if you can identify the ground wire connecting the ET to the main house panel.

 

[Rocket J Squirrel]

The 2 panels are at least 30 feet apart. Longer than my multimeter probes. Visual sounds good.

 

[JamesW]

The white neutral on a 240V CB does not carry any electricity in normal operation.

The neutral on a 240 breaker will carry current if the breaker feeds 120 and 240 loads at the same time.

 

[ajw22]

The 2 panels are at least 30 feet apart. Longer than my multimeter probes. Visual sounds good.

I have some spools of wire around the house to extend the reach of a probe when I need to check a long run.

 

[ajw22]

The neutral on a 240 breaker will carry current if the breaker feeds 120 and 240 loads at the same time.

Yeah, but you don't often do that with a pool panel. The 240V CB usually just feeds 240V devices in an ET panel.