Bill, Your branch circuit breaker is pretty small. Are you energizing both transformers simultaneously? If so, it might help to energize them individually.
The branch breaker can be up to 250% of the step up transformer's primary rating. 10kVA/240V=41A. 41A x 2.5=100A. (round numbers). To do this you would also need overcurrent protection on the transformer secondary. Of course, you've already got the 100A main tripping. That's why I asked if you're energizing them simultaneously. Transformer inrush can be a real problem. Hope this helps. Dick Ratico Solarwind Electric --- You wrote: Friends: I have on off-grid client that is trying to eliminate winter generator run time. He has a rental on another corner of the property that has grid power. When it was installed, he put in an extra meter, hoping to use it to run a utility back up feeder to charge batteries. We are now installing this feeder. We purchased two 10KVA 240/600 volt transformers to bump the voltage to 600 and then back down to 120/240. Here's the problem: when we energize the circuit breaker that feeds the transformer, the circuit breaker AND the main breaker trip. The transformer is 10KVA, the main is 100 amps and the branch breaker is 60A. The breakers hold sometimes but trip other times. This is obviously an inrush problem. How do I correct this problem? Thanks in advance, William Miller --- end of quote --- _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
