I have a main breaker feeding a subpanel approx 90' away in EMT conduit. Main breaker is a 250amp Square D with electronic trip unit Micrologic 6.0A. The load is 10 heaters in VAV boxes that are used very little.
The problem is that the breaker trips once in a blue moon mostly at night when no one is around. I have meggered the wire and get readings to eachother and ground over 16G Ohms at 500V @ 5min time. None of the branch circuit breakers has ever tripped. I have rasised the trip ratings to max and it still trips the breaker, installed new breaker and still tripped.
Any sugestions?? Thanks in advance!
The problem is that the breaker trips once in a blue moon mostly at night when no one is around. I have meggered the wire and get readings to eachother and ground over 16G Ohms at 500V @ 5min time. None of the branch circuit breakers has ever tripped. I have rasised the trip ratings to max and it still trips the breaker, installed new breaker and still tripped.
Any sugestions?? Thanks in advance!