GENERATOR WHILE PLUGGED IN

[SCOTT JORDAN]

I HAVE NEW (TO ME) 2003 ALLEGRO WITH AN AC TRANSFER SWITCH.  IS IT OKAY TO START GENSET WHILE PLUGGED IN?

 

[Just Lou]

Scott,  that should be no problem.  The transfer switch is designed just for that purpose.

 

[Ned]

Yes, most transfer switches give precedence to the generator, so after a brief (30 seconds or so) delay to allow the generator to come up to speed, the transfer switch will throw and you will be powered from the generator.  You can then unplug the shore power as there will be no load on it.

 

[John From Detroit]

I have done it, I will make one suggestion though  When the switch changes from shore to internal power there will be a brief interuption of power to things like the Air Conditioners, Electronics and such.  now most of the electronics can take a  brief power interpution without notice (My Motosat antenna is an exception, however it's not harmful)

The AC's however are another story... It's not nice hot switching a cmpressor, can cause the circuit breakers to go CLICK

Thus I'd suggest you turn off heavy loads such as the AC and hot water heater before fireing up the generator and thrn them back on after power is transfered (or 4 minutes later whichever comes last)

 

[Jim Godward]

Scott,

Generally the maker of the transfer switch will recommend against hot switching.  The contactor contacts are not usually rated for that.

I would recommend that you don't do it unless you have a very good reason to do so.  The extra minute or so should not make a big difference as the ACs etc. will lock out the restart for a couple of minutes anyway.

 

[Jackliz]

I HAVE NEW (TO ME) 2003 ALLEGRO WITH AN AC TRANSFER SWITCH.  IS IT OKAY TO START GENSET WHILE PLUGGED IN?

No, we NEVER do that, although our Blue Bird mechanic says it is OK. Jack has had more than 40 years working in electronics and he doesn't trust that switch. We shut off the breaker at the power post and then start the generator. I see from reading other replies that other RVers think that starting the genset while plugged in is OK BUT we NEVER do that. We met an RVer who ruined his genset and a lot of wiring in his Prevost because that transfer switch failed. Just another opinion.

Regards,
Liz

 

[John From Detroit]

Scott,

Generally the maker of the transfer switch will recommend against hot switching.  The contactor contacts are not usually rated for that.

I would recommend that you don't do it unless you have a very good reason to do so.  The extra minute or so should not make a big difference as the ACs etc. will lock out the restart for a couple of minutes anyway.

That is part of the problem,,, If you shut down, unplug and then start, no problem,  If you hot-switch, it does not reset the lock out timer (Remember I said most electrioncis won't care, that includes the lock out timer) but it will stop the compressor, so it tries to hot-start,  The result is that the compressor is (very termporally) siezed and it trips the breakers.  Of course by the time you can get to the breakers and reset them manually the AC is ready to restart

 

[Just Lou]

I was one of the earlier responders who said you could do the "hot switch" as it's been dubbed here.  I had done it a few times simply because the manual says you can.  However, Liz and James are correct to caution against it since it is not a necessary thing to do.

I meant to add this statement to my other post as well.

I once ruined an inverter (modified sinewave variety) that I had wired through a transfer switch by plugging into cg power before turning off the inverter.  The switch was wired to give preference to the cg/gen source, and the inverter was wired through the normally closed default contacts.  My problem was that the switch contacts either tacked temporarily or it was a make-before-break switch and the two sources collided and the inverter fried.  I have since rewired the transfer switch (a different one) to give preference to the inverter (a different one) and all is well.  Being either brave  (or stupid) I just had to try the hot switch to test it.  It has worked each time, but I'll not be doing it as a matter of course in the future.

Thanks for setting the thread straight Liz and James.  Bad advice (mine) is worse than NO advice.

lou

 

[SCOTT JORDAN]

THANKS FOR YOUR COMMENTS.  I GRADUATED FROM A CLASS C WHICH DIDN'T HAVE A TRANSFER SWITCH.  I DIDN'T HAVE TO WORRY WHEN EXERCISING THE GENSET.  I TRY TO RUN MY GENSET ONCE A WEEK AND DIDN'T KNOW HOW IMPORTANT IT WAS TO UNPLUG WHEN A TRANSFER SWITCH IS INVOLVED.

SCOTT

 

[Ned]

All of you are correct, just because you CAN do something doesn't mean you SHOULD do it.  In practice, there should never be a need to start the generator while still on shore power.