Generator hook-up

[fisherelectric]

Customer has a 40 KW generator that's been wired for 120/240 volt operation with a 180 amp breaker. His house has 2 200 amp service disconnects in the garage with 4/0 SER feeders running to load centers in the basement. He wants to install 2 manual 200 amp transfer switches between the disconnects and the load centers. He wants to run 4/0 SER from the generator to a trough beside the transfer switches and then run 4/0 into each transfer switch. Is that compliant?
He has gas heat and cooking and water heater. Five small AC units the largest of which has MCA 22 amps.

 

[qcroanoke]

Customer has a 40 KW generator that's been wired for 120/240 volt operation with a 180 amp breaker. His house has 2 200 amp service disconnects in the garage with 4/0 SER feeders running to load centers in the basement. He wants to install 2 manual 200 amp transfer switches between the disconnects and the load centers. He wants to run 4/0 SER from the generator to a trough beside the transfer switches and then run 4/0 into each transfer switch. Is that compliant?
He has gas heat and cooking and water heater. Five small AC units the largest of which has MCA 22 amps.

It seems to be a great idea! Pick which panel you want the genset to feed. As long as you don't close both disconnects and have both panels on the generator all would be good. But even if the homeowner closed them both, it's on him. He has to pick the load.
Wire sizing may play into this. It is 4/0 aluminum i assume?

 

[fisherelectric]

Yes, 4/0 al. He wants to close both switches at the same time. It's all mainly lighting loads except for the 5 AC units. Wasn't sure about bugging the 4/0 feeder from the generator to feed 2 200 amp load centers. I turned on 3 of the Ac units and a lot of lighting and the dishwasher and microwave while testing the service cables and never got over~28 amps per leg.

 

[360Youth]

The key thing is you are talking manual switches so the loads can be shed to accommodate the generator if necessary. Then it becomes a service design more than a generator design.

 

[frogneck77]

I dont see any compliance issues-your 4/0 coming from the generator are fused at the breaker at the generator.Its a similar design as the Generac load shed ATS/panel except for the manual control.

 

[hurk27]

The only problem I see is if the transfer switch's are not service rated (which means they will have OCPD in them), and the two panels will become sub panels requiring separated grounding and neutrals, also if the GEC's are landed in the panels they would have to be moved to the new point of the main bonding jumper in the transfer switch or ahead of it, maybe in the trough?

 

[kbsparky]

Ummm ... the OP stated that the service disconnects were in the garage. Those panels are already sub-panels....

 

[hurk27]

Ummm ... the OP stated that the service disconnects were in the garage. Those panels are already sub-panels....

U'mmm me thinks me needs to read OP more carefully:roll: