Running generator while plugging in

[David P]

Planning to run generator this summer while on the road for house air. Should we turn the air off first then shut the generator off before plugging into shore power?

[Bob Denman]

The transfer switch will take care of everything. You don't have to turn anything off...

[jannnda]

Originally Posted by David P

Planning to run generator this summer while on the road for house air. Should we turn the air off first then shut the generator off before plugging into shore power?

I am sure Bob is correct. However, I turn everything off then turn the gen off. Turn the power on before I have it connected to the MH and look at my surge protector to make sure I have a good source. I turn off the power, hook up the MH then turn on the breaker. Go back in the MH and turn on the a/c units. This is how I was told to do it when I owned a boat and was going from gen to shore power. Just my $.02.

[blw2]

I've always felt the better way is to shut off the load before switching..turn of the AC, water heater, microwave...before plugging in. I don't think it matters as much if you leave the genny running to cool down while you plug in, but I can follow the thought it makes sense to shut down cold before plugging in.

That said, I do believe it's made to be able to switch under load and I've never sweated it.

That said, i can't think of a time I didn't shut down the genny before pulling into the campground or park just to be polite to the neighbors...so I'm not sure if I've ever plugged in while the genny and AC were pumping.... although I probably have at some point.

[blw2]

the other thing....
ignoring the plugging in part for a moment
you are supposed to shut down the load and let the genny run a few minutes with low or no load to cool down, before shutting off the genny.
Sadly, I often don't do that because while I can shut down the genny from the driver's seat, I cannot control the AC

[Lt Keefer]

I try to take the load off before switching power sources or powering down. Don't know why other than we used to do it with the -60s on the flightline as well as with the paper shears at work.

[16ACE27]

Well you can plug into SP with the generator running but nothing will happen as the generator is the preferred power source for the ATS.

But before you shut that generator down you should minimize the AC load to minimize the arcing of the ATS contacts - they'll last longer that way.

[David P]

Thank you all for your helpful advice.

[Laco]

If all is working correctly, when you plug in, the load will shift from the generator to shore power, which will allow the generator to run for a bit with no load, to cool.

[16ACE27]

Originally Posted by Laco

If all is working correctly, when you plug in, the load will shift from the generator to shore power, which will allow the generator to run for a bit with no load, to cool.

Nope, generator power has preference. The ATS automatically shifts from SP to generator when power is available from both, not the other way around.

[dkoldman]

Quote:
Originally Posted by Laco View Post
If all is working correctly, when you plug in, the load will shift from the generator to shore power, which will allow the generator to run for a bit with no load, to cool.


Nope, generator power has preference. The ATS automatically shifts from SP to generator when power is available from both, not the other way around.
__________________
Ted & Melinda
2016 ACE 27.1
2016 Chevy Sonic Toad

I believe both statements are true ...

There are mitigating factors that are dependencies for the outcome.
i.e. Do you have AGS controller or not? If so, what brand? How is the AGS wired and programmed. It matters greatly if you have AGS if it is wired before or after ATS (XTR SW). Both ways can be wired correctly.

If you have the Onan Controller wired before ATS (XTR SW) it will do exactly what Laco states, Genset will shut off after a minimum runtime. If it is wired after ATS (XTR SW) it will do exactly what the ACE states and Generator will continue to run as preference forever as long as AGS is in Manual mode. However should the power be restored and Genset be in AUTO or QUIET TIME mode the Genset will run until a HVAC or Low Bat condition is satisfied to tell it to stop. Which kind of proves the ACE's point that the ATS (XTR SW) by itself (no AGS) prefers the Generator over Shorepower.

[ShadowT]

Originally Posted by David P

Planning to run generator this summer while on the road for house air. Should we turn the air off first then shut the generator off before plugging into shore power?

Your electronic transfer switch should work ok -for a period of time, but...If you like to stress switches out to "arc'en and sparkin' " causing wear is not good. The less current running across breakers the and less power fluctuation to circuits the better. Shut everything down first, then connect, let power stabilize a few minutes, then slowly power up the stuff you want to run. If you have extra monitoring of the power input for phasing, current, and voltage you will know what I mean.

[cofred]

I've been told that suddenly cutting the power to the A/C can cause problems with the compressor, so I always turn the A/C off before turning the genny off or disconnecting from shore power.

[Tinman]

The few times that I have started the generator to exercise it while plugged into shore power has usually resulted in tripping the shore breaker (happens at my house and at the last RV Park I stayed long enough to want to exercise the gen). The last time was a pain since the breaker that tripped wasn’t at the pedestal, it was upstream at the meter bank for this section of the park where I was. I try to remember to always unplug from shore power before starting the generator. I don’t know if plugging in while the generator is already running would cause
the same kind of surge that may trip a shore breaker but I would recommend unloading and shutting down the gen before plugging in.

[16ACE27]

Originally Posted by cofred

I've been told that suddenly cutting the power to the A/C can cause problems with the compressor, so I always turn the A/C off before turning the genny off or disconnecting from shore power.

Ummmmm........ What do you think happens when you "turn the A/C off" either manually or via the thermostat when the set temperature is reached? Power is suddenly cut to the A/C.

[Oneilkeys]

Originally Posted by cofred

I've been told that suddenly cutting the power to the A/C can cause problems with the compressor, so I always turn the A/C off before turning the genny off or disconnecting from shore power.

What causes problems is shutting down the compressor and starting it back up immediately. One of the reasons why a good voltage protector has a two minute delay before it turns on the power, is to protect the compressor from that happening from an intermittent or short loss of power.

[gte534j]

My PD5100 Automatic Transfer Switch owner's manual states:
Description of Operation
 When the shore power is applied the relay is at rest and power is transferred to the panel.
 When Generator power is applied there is a 20-45 second delay and then the relay activates transferring Generator power
to the panel.
 If shore power returns while the Gen power is present nothing will happen. When the Gen power is removed the relay will
drop out and allow the shore side to supply power.
 Generator overrides shore power.

[Beau388]

Originally Posted by 16ACE27

Well you can plug into SP with the generator running but nothing will happen as the generator is the preferred power source for the ATS.

But before you shut that generator down you should minimize the AC load to minimize the arcing of the ATS contacts - they'll last longer that way.

[twovillagers]

Originally Posted by David P

Planning to run generator this summer while on the road for house air. Should we turn the air off first then shut the generator off before plugging into shore power?

I'm probably conservative as I know the transfer switch can take care of it. The potential problem is arcing and pitting of the contacts in the transfer switch due to having a load.

I turn off the A/C, then the main breaker, and turn generator off. Then re-power with shore power.

[gte534j]

Originally Posted by twovillagers

I'm probably conservative as I know the transfer switch can take care of it. The potential problem is arcing and pitting of the contacts in the transfer switch due to having a load.

I turn off the A/C, then the main breaker, and turn generator off. Then re-power with shore power.

The Progr essive Dynamics, Inc. manual does not states weather or not you should remove load before it being transfered.

The manual does describe how to trouble shoot for pitting.

This might be something you want to contact the manufacturer to get clarification on about removing load before enabling the transfer switch to occur.