Went to a customer's house today that was having problems with their GFI tripping in their basement. All the basement lights, and recepts., plus condensate pump for AHU unit, and the alarm circuit for the sewage pump was fed off the load side of a GFI outlet. At first we didn't know what was tripping it. By troubleshooting it through the boxes, I traced it to the outside sewage pump control box. It controls the circuit board and alarm circuit floats. I disconnected the board and it cleared the circuit up. As far I can read, it is not required for a circuit like this to be GFI protected, in fact the pumps I have worked on in the past have had a separate circuit for the alarm circuit. It's holding now, but it probably will go out again. Not sure what in the control box is causing it. I first thought it might be one of the floats shorting out, but had plumbers check it and that does not seem to be the case. I did find out it was tripping between neutral and ground, and not hot to neutral. After thinking it through again, I'm thinking it may be in the circuit board somewhere, since the floats only break the hot and no neutral is involved. There have been some pretty bad storms here lately, so lightning may have something to do with it. But that all said, I've talked myself into running him a separate 15 amp circuit from the panel on a regular breaker if he calls again. If any other thoughts, I'm open... thanks.. Steve
I have learned that equipment that is not required to be protected by a GFI is not required to be free of ground faults. CSA told me to remove the GFI from steam tub equipment that was tripping the GFI. If the UL test is the same as CSA, it is a power off test. Anything that causes a fault after the equipment is energized is not noticed. I suppose that, since there are no other prescribed tests, they can't or won't change the standard for one piece of equipment regardless of the circumstances. Knowing this, I would also run a new circuit.
I don't know what the literature calls for. It was acting strange. It would work probably a day or so, then it would trip the GFI. I ended up going back and was going to wire it on a separate circuit, but there's no access in the ceilings and it would take a lot of exposed conduit on the outside of a $400,000.00 house to do it, so for now I put it on the line side of the GFI, and it is holding. The "fault" was between neutral to ground, I do know. It's a mystery to me for now. I might see if I can pull up some information on the manufacturer, and ask them, if I can remember the name of the pump control:(