Breaker tripping on retransfer

[RUWired]

Typically the generator cannot supply high in rush currents equivalent to the bus from the utility.

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We had a similar problem with a U.P.S. and a transformer for the load. Going to generation would be fine, going back to utility would trip the ups out. Turned out the transformer in rush was to large for the u.p.s.

 

[dbuckley]

If the inrush current is the same, then either the inrush time is longer, or, as there is now more load, you're just a bit further along the breaker current/time sensitivity curve. Perhaps a slower breaker needed?