Last spring I was called about a problem with a main breaker tripping. It was in an unoccupied building that was previously used as a pharmaceutical research & manufacturing facility. One of the breakers in the main switchgear would occasionally trip for no apparent reason, and half the building would be in the dark. I checked for any obvious causes of the problem and found nothing. I walked through the facility and shed as much of the load as I could. For example, there was a small power conditioner that was buzzing like hell, so I shut it down. Turned off the disconnects for some high-tech research equipment. Pretty much left nothing on except lights and HVAC. About a week later I get the call, it tripped again. The breaker is a Westinghouse DSL-206, and I found an Amptector Tester in the maintenance office. I contacted the manufacturer and obtained the manual for the tester, as well as the curves for the breaker. None of this was really useful to me, as I have no experience with this type of stuff. In the past, once the wire is pulled and terminated, the tech shows up to set up the breaker. But now I'm working for myself, so here I am. Anyway, I plugged in the tester and went through the steps. I wrote the numbers down and looked at the curves. And the curves were exactly that: a page of curved lines and some numbers I couldn't read. I couldn't make heads or tails out of it, but I think my daughter would enjoy coloring them in. So I just tweaked all the settings on the breaker. Turned everything up one notch. Long delay, short delay, etc. I know thats not the right way to solve the problem, but the building is unoccupied and the owner doesn't care to call in a team of experts. He just needs to keep the power on so the mag locks stay energized. I checked the building every week for 8 weeks, and the breaker did not trip. Until this past Monday (four months later). Also, there is a digital IQ meter on the gear which shows an overvoltage alarm every time I go there. About 505 volts line to neutral. Any advice would be appreciated. Is my next step to contact the utility, tweak the breaker settings a little more, or swap out the breaker with the spare that happens to be in an adjacent cabinet?
Thanks,
John
Thanks,
John