Let me start by apologizing for the size of this beforehand. I'm going to do my best to explain my issue as thoroughly as possible.
I'm working in a Govt. building that has had multiple additions over the years and the electrical work does not look pretty. The issue I'm having is a GFCI(brkr 24) tripping only when another s/p(brkr 8) standard(non GFCI or AFCI), is on. I turn off the s/p brkr 8 and the GFCI brkr 24 will no longer trip. I unplug everything fed from s/p brkr 8 and the GFCI brkr 24 will no longer trip. s/p brkr 8 never trips.
I traced out the wiring and found that the neutral for s/p brkr 8 is shared with the neutral for the GFCI brkr 24. They tie in together, about 100 ft through conduit bends after the GFCI brkr 24. And both hots are in the same conduit run.
I tried disconnecting the hot for the s/p brkr 8 at the first available junction box and it will still trip the GFCI brkr 24. This is also the same location that the neutral all tie in together.
My thoughts are that because of the shared neutral, after the GFCI brkr 24, the GFCI brkr 24 is detecting the 5/1000 of an amp difference coming from the s/p brkr 8 in the conduit run within the first 100 ft.
I am slightly skeptical of this and before I start running new wires into a run that is almost at it's max wire capacity. I wanted to verify that this is a possibility and the most likely of problems.
I'm working in a Govt. building that has had multiple additions over the years and the electrical work does not look pretty. The issue I'm having is a GFCI(brkr 24) tripping only when another s/p(brkr 8) standard(non GFCI or AFCI), is on. I turn off the s/p brkr 8 and the GFCI brkr 24 will no longer trip. I unplug everything fed from s/p brkr 8 and the GFCI brkr 24 will no longer trip. s/p brkr 8 never trips.
I traced out the wiring and found that the neutral for s/p brkr 8 is shared with the neutral for the GFCI brkr 24. They tie in together, about 100 ft through conduit bends after the GFCI brkr 24. And both hots are in the same conduit run.
I tried disconnecting the hot for the s/p brkr 8 at the first available junction box and it will still trip the GFCI brkr 24. This is also the same location that the neutral all tie in together.
My thoughts are that because of the shared neutral, after the GFCI brkr 24, the GFCI brkr 24 is detecting the 5/1000 of an amp difference coming from the s/p brkr 8 in the conduit run within the first 100 ft.
I am slightly skeptical of this and before I start running new wires into a run that is almost at it's max wire capacity. I wanted to verify that this is a possibility and the most likely of problems.
