Electrical Services Larger Than 1200A

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SparkyKurt

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SW Michigan
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Electrical Contractor
Hey there everyone,

I just signed up because of a new project I'm getting involved with. It's a large commercial grow operation that currently has 10 greenhouses that are 24' wide and 132' long. Each of these greenhouses will have a 200A, 240V 3-Phase panel in it that I'm trying my best to limit to 160A of load. (80%) That alone is going to be a challenge, but I've got that problem under control. What I need help with is the main service.

My expectation is that I will need an electrical service larger than 1200A, and 1200A is the largest service I've ever designed and installed. I don't even know what comes after 1200A. It's just never come up as something I needed to know. Is there a 1600A and a 2000A? If so I've never heard of them. I'm supposed to be coming up with some design ideas to run past the project coordinator and to discuss with the utility company.

Anybody got something for me on this. I'm sure some of you have installed electrical service equipment and switchgear to control loads that were larger than 1200A. Let me hear some of your war stories, listen to your suggestions, hear your advice! I need INPUT!
 
I have done designs for 1600, 2000, 3000, and 5000 amp services. Beyond that, it becomes tricky to get metering that satisfies all requirements. Keep in mind that at and beyond 1200 amps, you may need two paths of egress from the working space. Check out NEC 110.26(C)(2). That's all I have time to offer at present, other than welcome to the forum.
 
You can have up to six disconnecting means per allowed service. Some instances it may cost much less to go with 2 or three 600, 800 or even 1000 amp service disconnecting means vs 1600 or 2000 or more for a single disconect. Plus down the road you can possibly isolate smaller areas of the site for service or other work without needing to shut entire site down.

Some times if POCO can't or won't supply what you need in a single service you have no choice but multiple services. NEC does take this into consideration when determining maximum number of services allowed.
 
Often it's advisable to consult with the POCO before you design your service(s). They will tell you want you can and can't have and that will help to narrow the options.
 
With that kind of load, and considering voltage drop, depending where you put the service, I would consider a 480 volt service, and a transformer at each greenhouse panel. That would cut your service size in half, along with being more poco friendly.
 
hillbilly1 said:
With that kind of load, and considering voltage drop, depending where you put the service, I would consider a 480 volt service, and a transformer at each greenhouse panel. That would cut your service size in half, along with being more poco friendly.
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Might even be possible to buy mostly 480/277 V equipment in the greenhouses if it has not already been purchased. Could be it is already dual rated for fans, motors, heaters even if it has been purchased.
 
I agree with the others about using 480 instead of 240. I did a grow and talked them into 480, saved a ton of wire and conduit.

Regarding the size, note that panelboards go up to 1200 amps, but you can go with multiple ones using 230.40 exception #2 to make a larger service. For single equipment larger than 1200, you are into switchboards which are technically a different animal but really it wouldnt effect you much, just talk to a gear guy at the supply house and he will get you what you need.

Find out from your POCO about metering. Many/most will take care of metering in the transformer. If you need to provide metering, switchboards can be ordered with metering sections.
 
electrofelon said:
I agree with the others about using 480 instead of 240. I did a grow and talked them into 480, saved a ton of wire and conduit.

Regarding the size, note that panelboards go up to 1200 amps, but you can go with multiple ones using 230.40 exception #2 to make a larger service. For single equipment larger than 1200, you are into switchboards which are technically a different animal but really it wouldnt effect you much, just talk to a gear guy at the supply house and he will get you what you need.

Find out from your POCO about metering. Many/most will take care of metering in the transformer. If you need to provide metering, switchboards can be ordered with metering sections.
Click to expand...
Switchboards are more customized and factory assembled to the application and will likely have a longer lead time where a real panelboard (as in not a loadcenter) is also customized but with those you often can order needed components from stock and field assemble most configurations, something to take into consideration.
 
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