I am a licensed electrician and I installed a 5000watt Reliance generator transfer switch for a friend, I put the master bedroom , fridge,well pump,furnace,and family room on the gentran switch,powered it with a Generac 5500watt generator, everything seems to be fine,except that when I power up the master bedroom with the generator, the 120v smoke detectors go into alarm,everything else seems to work fine. The house was built in the early seventies, and the smoke detectors were made by Bittenhouse.I can not find a reason why the smokes would go off under the generator power, any ideas?

So we are talking about a 120 v / 9vdc detector right? It has a battery backup or no?

No there is no battery back-up just 120v.

I'd swap it with one from another bedroom to see if its just a touchy alarm. Does it trip if you switch the breaker off and back on?

It does not trip with just using the breaker, it only trips when powered by the generator,also there are six smokes wired together and they all trip when powered by the generator.

I forgot to ask but aren't all the detectors on their own dedicated circuit? Is it one that you are powering with the generator?

The smokes are on the master bedroom circuit, and if it makes a difference it is the same circuit that powers the upstairs hall and bathroom light.