Load Shed a Pool Panel

[JAMAN]

What I'd like to do is load shed a 200A single phase MLO Pool panel from an existing whole house standby generator w/service rated ATS. Basically, automatically disconnect the pool panel from the generator when utility power is out and automatically connect power back when utility power is back on.

Is there equipment that can get wired ahead of the Pool panel that will do as described above?

Other suggestions are welcomed as well.

Thanks for your help.

 

[augie47]

A contactor or motor operated breaker would do so, but both are expensive.
What is the predominant load ? It may be something you can interrupt a control circuit at a lot less expense,

 

[JAMAN]

Wow, I feel like such an idiot. I never even thought of a contactor. There aren't any interruptable control circuits, so maybe a contactor is the way to go.

How would the coil get energized? Would it get wired to an auxillary contact on the existing ATS?

 

[kingpb]

Just to load shed, you would have to return the load manually, would be to use a shunt trip breaker that initiates off a contact of the ATS.

 

[augie47]

Probably an auxiliary contact would be best. If you connected directly to utility supply the contactor would try to close immediately and there is usually a delay to assure restoration before the ATS switches.

 

[JAMAN]

The owner would like the load to return automatically. The contactor would work, it's just a matter of how the coil gets energized.

Could the ATS provide the power to energize the coil?

 

[foqnc]

Never mind I just read Augie's post above better.

 

[hillbilly1]

I have used relays to interupt the control voltage on A/C units, as well as pool equipment. There is two easy ways to do this, one is to use an auxillary contact on the transfer switch, if available, to control a relay to fail open, controlling a contactor or other control device(s). The other is to power the relay from the generator output to open the control circuits. The main problem doing it this way is that while the generator is exercising without load, everything will be shedded regardless of the transfer switch position. I have also used current sensors to shed the load if the load gets too high. But that gets a little more complicated.

 

[KP2]

You can tap off of the monitoring circuit in the ATS and feed a the contactor with 240 volts. This way the monitoring voltage will energize the contactor and when you loose utility the contactor will drop out and shed the load.

When the Generator exercises the contactor will stay on.

Connect to N2 and N2 of this Generac ATS or something like it.

 

[LarryFine]

I would like to add one thing to KP's suggestion: use N1 (he meant) and N2 to power a smaller relay, and use that to power the contactor.

I wouldn't want to place the current of the coil of a 200a contactor on those terminals, not without knowing the available current there.

 

[KP2]

I would like to add one thing to KP's suggestion: use N1 (he meant) and N2 to power a smaller relay, and use that to power the contactor.

I wouldn't want to place the current of the coil of a 200a contactor on those terminals, not without knowing the available current there.

Thanks For the N1 edit and I like the add on.

 

[dbuckley]

The only grump with a contactor in a resi is that its humnming away 24/7 using power which the homeowner is paying for. If you can make it work with motorized breakers, even at a higher initial cost, it should pay dividends every day of the week.

 

[LarryFine]

Mechanically held?

 

[dbuckley]

Mechanically held?

Yep, another good idea.

 

[kwired]

I wouldn't want to place the current of the coil of a 200a contactor on those terminals, not without knowing the available current there.

I don't understand your concern with the coil and available current, concern of properly rated switches or overcurrent devices I do understand. If too much available current for control devices use a control transformer.

 

[LarryFine]

I don't understand your concern with the coil and available current, concern of properly rated switches or overcurrent devices I do understand. If too much available current for control devices use a control transformer.

What I mean is a 200a contactor may have a 5a coil current, but the monitor circuit may not be able to supply that.

It very well may, but I'm just saying I'd want to be sure first.

 

[hillbilly1]

You can tap off of the monitoring circuit in the ATS and feed a the contactor with 240 volts. This way the monitoring voltage will energize the contactor and when you loose utility the contactor will drop out and shed the load.

When the Generator exercises the contactor will stay on.

Connect to N2 and N2 of this Generac ATS or something like it.

The problem with using the utility sense circuit is the generator does not imediately transfer back when utility returns, it has a time delay in case the utility is dropping in and out. It would close the contactor, throwing the entire load onto the generator.

 

[LarryFine]

Good point. My intermediate relay needs a time delay, say 5 minutes longer than the T/S's back-to-utility timer.