400 amp service, 200 amp panels in two buildings...generator and switches

[stedder]

Just asked to look at, ballpark a job for a generator install. 320 amp o/h service set up with 320 amp meter, out the bottom to 2, 200 amp disconnects. from there both go into the house. one goes immediately into a 40 ckt mb panel which serves the house. Second goes through basement in 2" conduit, back out the other side of the basement, underground to a large 3 car garage with another 200 amp mb panel, both are set up as subs.
in the garage which has shortened depth there is a small apartment and above the garage and rear apartment is another, much larger apartment.
my question is; is there any reason I can't mount 200 amp AT switches, one in the basement of the house and one in the garage at its panel location? And, do they need to be service rated due to the fact that there are disconnects immediately after the meter?

 

[James L]

You can put the transfer switches near each panel.

 

[Canton]

Just asked to look at, ballpark a job for a generator install. 320 amp o/h service set up with 320 amp meter, out the bottom to 2, 200 amp disconnects. from there both go into the house. one goes immediately into a 40 ckt mb panel which serves the house. Second goes through basement in 2" conduit, back out the other side of the basement, underground to a large 3 car garage with another 200 amp mb panel, both are set up as subs.
in the garage which has shortened depth there is a small apartment and above the garage and rear apartment is another, much larger apartment.
my question is; is there any reason I can't mount 200 amp AT switches, one in the basement of the house and one in the garage at its panel location? And, do they need to be service rated due to the fact that there are disconnects immediately after the meter?

Appears you have (2) structures, residential application with a “House and an Accessory structure “ If so, both will need a GES established. The 200 amp feeder going to the “Garage/Apartment “. will need a disconnect, MBP will work.

Not sure where you are putting the generator, but yes, an ATS can go at both locations. Does not need to be Service rated.

 

[LarryFine]

my question is; is there any reason I can't mount 200 amp AT switches, one in the basement of the house and one in the garage at its panel location? And, do they need to be service rated due to the fact that there are disconnects immediately after the meter?

With disconnects at the meter, that ends your service; everything downstream is feeders and sub-panels.

 

[stedder]

Yes transfer switches directly adjacent to main panels.
seemed like the simplest way to do it.
Generator nearest to the main service.
Thanks for your positives.

 

[LarryFine]

Okay, I wish to add:

I would either put both ATSs next to the two service disconnects, or replace them with service-rated ATSs. I have done both, depending on the existing equipment and holes in the building.

That is the easiest way to intercept both exidsting feeders, have everything in one location, and keep the generator feeder lengths to a minimum, especially with the generator nearby.

 

[James L]

Okay, I wish to add:

I would either put both ATSs next to the two service disconnects, or replace them with service-rated ATSs. I have done both, depending on the existing equipment and holes in the building.

That is the easiest way to intercept both exidsting feeders, have everything in one location, and keep the generator feeder lengths to a minimum, especially with the generator nearby.

I disagree. I've done both ways, and by far the easiest have been to put the ATS right next to an existing subpanel.

Remove feeder from subpanel, dump it into ATS, install short feeder from ATS to subpanel.

That way can be done in a couple of hours and power back on to subpanel before any work is done on generator.

Plus, if there are (2) 200a disconnects outside, swapping to 2 ATS is gonna take up more space meaning SER feeder cables aren't in the right place anymore - and 99% guarantee they aren't long enough to land in ATS.

no way I'd open that can of worms if ATS can be set right next to subpanel inside

 

[stedder]

Wait...I have to mount both switches in the basement since I need control and gen feeders at both switches. There is no way sans trenching, to get out to the garage. Starting to wonder if a dual 400 amp switch in the basement would be better. More expensive equipment but less labor. I'm old and busy, I don't need any more labor than I need!

 

[James L]

Wait...I have to mount both switches in the basement since I need control and gen feeders at both switches. There is no way sans trenching, to get out to the garage. Starting to wonder if a dual 400 amp switch in the basement would be better. More expensive equipment but less labor. I'm old and busy, I don't need any more labor than I need!

If you can intercept the garage feeder in the basement, that would make it easier than installing transfer switch next to the panel

 

[kwired]

Wait...I have to mount both switches in the basement since I need control and gen feeders at both switches. There is no way sans trenching, to get out to the garage. Starting to wonder if a dual 400 amp switch in the basement would be better. More expensive equipment but less labor. I'm old and busy, I don't need any more labor than I need!

Might need to use master/slave features on the ATS units

 

[LarryFine]

I disagree. I've done both ways, and by far the easiest have been to put the ATS right next to an existing subpanel.

We're talking about feeders to two separate buildings here. Two generators, I would agree with you.

What's easier, space permitting, than mounting an ATS next to a disco with a nipple between them?

(Feeder, and even service conductors can be extended.)

Plus, if there are (2) 200a disconnects outside, swapping to 2 ATS is gonna take up more space meaning SER feeder cables aren't in the right place anymore - and 99% guarantee they aren't long enough to land in ATS.

As I said, I have done it both ways (replacing and nippling), depending on the situation.

I have also installed ATSs at the panel. Not too long ago, a pair above a pair of panels.