First time generator and ATS hookup

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nickelec

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I'm going to be installing a natural gas generator for a buddy but I never did one before it's a generac generator with ats I'm pretty sure I'm ok with wiring the line and load off the meter etc but in familiar with the control wiring if any can anyone she'd some light or some.advice on this install

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Here are some pics of ats
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The home was wired with the thought if adding a generator in the future but I have not gone in to see what exactly was installed

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nickelec said:
I'm going to be installing a natural gas generator for a buddy but I never did one before it's a generac generator with ats I'm pretty sure I'm ok with wiring the line and load off the meter etc but in familiar with the control wiring if any can anyone she'd some light or some.advice on this install

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Read thru the transfer switch manual. You'll be able to figure it out. Pretty straight forward.


https://www.electricgeneratorsdirect.com/manuals/rts_inst_man_2013.pdf

Joe Villani
 
Is there anything else that's needed like an extra contactor or relay I've red some older thread's and this was discussed I'm not sure if it was in regards to a certain setup or add on


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nickelec said:
Is there anything else that's needed like an extra contactor or relay I've red some older thread's and this was discussed I'm not sure if it was in regards to a certain setup or add on


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That would be necessary only if the generator isn't sized to power all the house loads, including in-rush for things like air conditioning. Then you would need to shed loads using relays designed for this purpose.
 
First time generator and ATS hookup

nickelec said:
Is there anything else that's needed like an extra contactor or relay I've red some older thread's and this was discussed I'm not sure if it was in regards to a certain setup or add on


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That’s a generac “smart switch”.

You can connect the HVAC units to those built-in relays for load-shedding. You just need two wires to intercept the power from the t-stat.

Generac makes a wireless 50A load-shedding relay that will sync up to this ATS for other loads like the water heater, range, dryer, etc. you can install them at the appliance. They’re $120/ea.

https://www.homedepot.com/p/Generac-SMM-Smart-Power-Management-Module-6873/206643494

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nickelec said:
Is there anything else that's needed like an extra contactor or relay I've red some older thread's and this was discussed I'm not sure if it was in regards to a certain setup or add on


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Many ATS's now have the ability to control the HVAC system's call for the air conditioner compressor. They do this by intercepting and controlling the 24VAC out to the compressor starter. This is done for two (and possibly three) reasons:

1) to keep the inrush from a running AC compressor from loading the generator along with all other loads in he house when the ATS transfers to the genny. It will allow the compressor to run once other loads have transferred and the generator is running them.

2) the ATS will keep the compressor off for approximately five minutes after transfer (from or back to utility power), to ensure the compressor isn't short-cycled by the quick off-on that transferring creates; it prevents damage to the compressor.

3) (possibly) set up to shed loads, including AC compressor, if the generator becomes overloaded.


It's supposed to be optional to hook this feature up, (at least on Millbank genny/ATS setups) but it's cheap insurance against a damaged AC compressor and/or stalled generator.


SceneryDriver
 
So it looks like the ats I have has a separate m module in it for AC hook up .do the AC load circuits need to be hooked up to this and the 24 volts as well?

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Problem is the thermostat is pretty far from where the Ats will be mounted

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brantmacga said:
That’s a generac “smart switch”.

You can connect the HVAC units to those built-in relays for load-shedding. You just need two wires to intercept the power from the t-stat.

Generac makes a wireless 50A load-shedding relay that will sync up to this ATS for other loads like the water heater, range, dryer, etc. you can install them at the appliance. They’re $120/ea.

https://www.homedepot.com/p/Generac-SMM-Smart-Power-Management-Module-6873/206643494

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What a great idea. Has it been reliable in the applications you installed them in?
 
nickelec said:
So it looks like the ats I have has a separate m module in it for AC hook up .do the AC load circuits need to be hooked up to this and the 24 volts as well?

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You only need two wires for make/break of the 24v line; you don’t have to go to the t-stat, you can intercept it at the unit.


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Knuckle Dragger said:
What a great idea. Has it been reliable in the applications you installed them in?
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Yes..... no idea how they actually sync themselves to the generator though. I’ve always been curious what would happen if you had a nearby ATS at a neighboring house.

They automatically shut off when standby power comes on for up to 5 min, and then the ATS will signal them to close if not overloaded.


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nickelec said:
Problem is the thermostat is pretty far from where the Ats will be mounted

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18-2 thermostat wire is cheap; you only have to break the 24VAC control line. It's not necessary to break the power conductors to the AC compressor.


SceneryDriver
 
brantmacga said:
Yes..... no idea how they actually sync themselves to the generator though. I’ve always been curious what would happen if you had a nearby ATS at a neighboring house.
They automatically shut off when standby power comes on for up to 5 min, and then the ATS will signal them to close if not overloaded.
Click to expand...

Based on my reading of the manual for the device, there is no signalling or connection of any type between the smart module and the ATS. (There is no radio signal.) The smart module just monitors the genny frequency and sheds the load if the genny goes below 58 hz for 3 seconds. This means all of the installed smart modules (up to 8) will shed simultaneously. They will reconnect the load after a time delay (if the genny is running above 58 hz). The time delay is determined by the priority setting. No two devices are supposed to be set to the same priority. Priority 1 reconnects after 5 minutes and each priority after that is delayed by an additional 15 seconds. Based on this, you could use these smart modules with any brand of ATS or even a manual TS.

ETA: They can be installed anywhere you can intercept the circuit. At the panel seems most convenient, but they can be installed next to the device as well. The case is NEMA 3R and there are 1/2" KO's. They only work with 240V loads. Not sure why you would want to shed a 120v load, but somebody at Home Depot's site asked this question.
 
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Coppersmith said:
Based on my reading of the manual for the device, there is no signalling or connection of any type between the smart module and the ATS. (There is no radio signal.) The smart module just monitors the genny frequency and sheds the load if the genny goes below 58 hz for 3 seconds. This means all of the installed smart modules (up to 8) will shed simultaneously. They will reconnect the load after a time delay (if the genny is running above 58 hz). The time delay is determined by the priority setting. No two devices are supposed to be set to the same priority. Priority 1 reconnects after 5 minutes and each priority after that is delayed by an additional 15 seconds. Based on this, you could use these smart modules with any brand of ATS or even a manual TS.

ETA: They can be installed anywhere you can intercept the circuit. At the panel seems most convenient, but they can be installed next to the device as well. The case is NEMA 3R and there are 1/2" KO's. They only work with 240V loads. Not sure why you would want to shed a 120v load, but somebody at Home Depot's site asked this question.
Click to expand...

I originally thought it just sensed the frequency until I viewed the flow chart in the manual. Shortly after the module powers up it checks power source utility/generator. see attached
 

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Coppersmith said:
Based on my reading of the manual for the device, there is no signalling or connection of any type between the smart module and the ATS. (There is no radio signal.) The smart module just monitors the genny frequency and sheds the load if the genny goes below 58 hz for 3 seconds. This means all of the installed smart modules (up to 8) will shed simultaneously. They will reconnect the load after a time delay (if the genny is running above 58 hz). The time delay is determined by the priority setting. No two devices are supposed to be set to the same priority. Priority 1 reconnects after 5 minutes and each priority after that is delayed by an additional 15 seconds. Based on this, you could use these smart modules with any brand of ATS or even a manual TS.
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:thumbsup: couldn't have said it any better

Remember the prime mover is only going to have a rating about the same as the generator, at is nears full load it is going to slow down a little - that is when frequency will drop.

This concept would not necessarily work on an inverter output unit though.
 
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