1200 Amp MCB And 130kW Generator

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Seven-Delta-FortyOne

Seven-Delta-FortyOne

Goin’ Down In Flames........
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Humboldt
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EC and GC
I’m going down to look at this job next week.

I haven’t done a lot of the larger industrial Generacs yet.

They have a 130kW Generac installed, and they say they have a 1200 Amp main.

Right now, the generator only runs 2 of the 8 sub panels, through two 200 amp ATS.

They want to run the entire facility

I see that Generac has specs sheets for 1200 Amp ATS, but I haven’t seen any actually for a sale. Rep at the supply house is looking into it for me.

There is a 1200 amp main, with distribution, with 8, 200 amp sub feeds.

The other option is to mount a giant can, and run a feed to 8 individual ATS from the load side of each sub feed.

Any glaring advantage or disadvantage to either option?

The room is fairly small, so I would probably put whatever I decide on outside. I doubt there’s room for the spiderweb of conduits on the inside.
 
I'm leaning toward the individual ATSs for several reasons, in no particular order:

Cost. You need to compare both materials and labor for each option. Two200a ATSs are cheaper than one 400a ATS. I don't know if that applies to your sizes.

Ease. I don't know your layout, but it's usually easier to run genny feeders to several ATSs than to re-route the entire supply feeder to a single ATS and back.

Space: I envision a room with several disconnects above or below a trough. I would look at placing ATSs below or above, and nippled to the trough.
 
That’s one of the big things. I can’t find a 1200 A ATS actually for sale, so I don’t know what pricing might be on that.

I can’t find a pic of the panel board, but it has a main on top, and 8 200 amp breakers below.

If there’s enough room on the wall outside, I’d thought of stubbing through the wall with all the feeders, and hitting the 8 ATS’s.

I would need one big #$$ can with terminal bars, for the generator feeder, and Then split to the ATSs.

Might end up being easier than dealing with separating N-G bonds in the main switchgear as well.
 
Can you describe how the existing ATSs are installed, and why you couldn't merely duplicate it?
 
Not sure yet. I’m going down to do a complete load Calc and give them an assessment on what they need.

I k is they have 2, 200A ATS inside the room, on the other side from the switch gear.

They supply only 2 of the 8 sub panels. Theres quite a bit of conduits runs, lighting control panels, and other stuff in the room.

I could duplicate it, although I’d try to move them outside, just for space considerations.

I was just brain storming about the possibility of just doing one large ATS. I’m not sure how these are most commonly done. I’m just now branching out into the larger industrial generators.
 
Usually there is not enough room to add more transferswitches, or even one large one. We usually just use a pad mount or wall mount SE rated 1200 amp switch between the transformer and the old gear outside, making the old gear a sub, and separating the neutral and grounds there. Sounds like this is an open facility, so that would give the least downtime when switching over. Usually can do the switchover in 8-10 hours. Without seeing it, hard to say if that is feasible in this situation.
 
hillbilly1 said:
Usually there is not enough room to add more transferswitches, or even one large one. We usually just use a pad mount or wall mount SE rated 1200 amp switch between the transformer and the old gear outside, making the old gear a sub, and separating the neutral and grounds there. Sounds like this is an open facility, so that would give the least downtime when switching over. Usually can do the switchover in 8-10 hours. Without seeing it, hard to say if that is feasible in this situation.
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That was my though, was that this scenario would be the most simple.

Im still looking for the 1200 amp ATS though.
 
Building on Augie's question, presumably there will be some stuff you don't want/need on the generator. Can you get the demand from the utility? You probably don't need a 1200A service or ATS so feel free to downgrade it. Besides seems silly to use a 1200 ATS when you only have a 130kw generator. You could always leave one or two of the parallel sets capped off to feed a 200 or whatever down the road if you needed it. What about supplying a 400 or 600 ATS and then 1 or 2 200 amp panels for non generator loads?

I can tell you what I did on a recent project, maybe it will spur some ideas. 120/208 1000A MLO panelboard, 150kw generator, 600A ATS. Put a 600A breaker in the MLO to feed the xfer switch( non service rated)
Left a few 200s in the MLO not backed up which did their autoclaves and most HVAC that we didn't need on the generator. ATS then fed a 600A panelboards which feeds like 6 200 amp and 3 100A panels (load is only about 320A max).

Another job I put like 5 200A panels on a 70KW generator/ 200A ATS. load is about 140A. It takes a little soul searching at first to do this but the fact is a lot of panels have little load. Put an EKM meter on it if you want.
 
That’s sort of what they have now, with the ATS supplying only 2 panels, I guess what were considered critical loads at the time.

They are making the facility an emergency community center, and right now, I guess the heat doesn’t run on gen power, the public showers don’t have lighting, etc., etc.

So they are wanting the entire facility to run as if nothing happened.
 
Seven-Delta-FortyOne said:
That was my though, was that this scenario would be the most simple.

Im still looking for the 1200 amp ATS though.
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Eaton and Square D both make motorized breaker transferswitches that are service rated, but are probably built to order. So expect a long lead time. Eaton had a plant in Arden NC that built them, but I don’t know if they still build them there.
 
Several other things to think about, one of the two existing transferswitch’s probably feeds life safety (emergency lighting), so you will need two breakers in the generator to stay compliant. (If you end up reusing the existing generator, it probably already has two.)
 
hillbilly1 said:
Several other things to think about, one of the two existing transferswitch’s probably feeds life safety (emergency lighting), so you will need two breakers in the generator to stay compliant. (If you end up reusing the existing generator, it probably already has two.)
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Thanks. I was thinking about that, I’m not sure what their legal status is, but I know there is a whole other set of rules for Legally Required Standby generators.

Definitely a newer area for me, as I mostly do residential and light commercial work, and I’m just starting to tackle some of these big boy jobs. 😂
 
Something else I’m wondering, I know that with the air-cooled units if you do more than 2 ATS, you need a relay, I believe it was for the 12v control wiring.

The liquid cooled units only have 2 control wires, so I don’t know if relays are needed, or if everything can just be paralleled in a gutter below the ATS?

Wheres @ATSman ?

There is a very qualified EC I’ve known for years, he was one of the J-men when I started out as an apprentice in the late 90’s. He does a lot of design work, and I’ll have him go over my plans and concepts.
 
When I have put two ATSs on a Generac, the instructions showed how to wire them as a master/slave pair.
 
LarryFine said:
When I have put two ATSs on a Generac, the instructions showed how to wire them as a master/slave pair.
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I’ve heard of that, but I’ve never seen rise directions. Probably buried on the Generac website somewhere.

When I did the factory training this year with Generac, he said that 2 ATS are just wired in parallel, nothing else needed.

Im doing an air cooled one now where there in one genny for two houses, 2 service panels. Im just going to parallel it in a gutter below the 2 ATS, and feed them both.

Hope that works. 😲
 
When you get into things of this size class, you really ought to be using standard 2-wire start generators and transfer switches.

This master/slave generator controlled ATS nonsense is for minimum budget homeowner air cooled haul it in a pickup generator installations.
 
Birken Vogt said:
When you get into things of this size class, you really ought to be using standard 2-wire start generators and transfer switches.

This master/slave generator controlled ATS nonsense is for minimum budget homeowner air cooled haul it in a pickup generator installations.
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I know. The one I’m doing with two ATS is a residential install with a 26kW air cooled.

The other one I’m looking at is a liquid cooled, 130kW, that I’m deciding if I should try to find a 1,200amp ATS, or use 8, 200 amp ATS. It has a two wire start.

Im was just wondering what the special conditions for the two wire ATSs are, when you have multiples.

Im currently going through some more Generac courses that they offer for the liquid cooled commercial units.
 
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