3 panels vs 1 panel - help me follow the logic here?

[Rep]

Gentlemen (and ladies). I have a best practices question that I humbly request an expert opinion on.

600 amp 3 phase 208Y/120 service. Comes into a CT Cabinet and then I want to distribute it to various breakers, mostly single phase 20 amp but a few 3 phase 40 amp.

My contractor thinks 3 separate 200 amp breakers is the way to go. I think 1 600 amp panel is easier, although possibly more expensive. Code is not clear to me and I wanted an outside opinion. The service feeders are a single set of wires. It seems like more work and unneeded redundancy to have 3 separate main breakers rather than a single 600 amp breaker.

I can follow his logic but I don't know why in an emergency, needing to turn off three separate panels to turn power off is considered permissible, even if they are situated in the same area. There has been no talk of a main disconnect.

 

[220/221]

My first instinct is to go with 3 main breakered panels.

Lots of reasons will come to mind the longer I think of it.

The first will be more space.

Second, supply and demand will make the materials less expensive.

Third, maintenance and additions to the system will be easier which equals saving future resources.

Fourth, I don't like to wrestle big wire any more than necessary

 

[Rep]

I follow the logic - take it from the CT (outside the building), take it to a gutter (inside) and then 3 separate 200 amp main panels (inside). I will need to check with the PoCo to see if their meter has a disconnect or not. Even if it did, there would be no easy way to kill all power without going outside or opening 3 separate panels and throwing the breakers. Seems like a potentially unsafe situation. It might come down to simply pricing out the 600 amp panel, realizing that makes no sense and deciding to just go for 3 separate panels.

 

[LarryFine]

Fifth, welcome to the zoo! :smile:

Rep, how many circuits of each ampacity are we talking about?

 

[augie47]

Rep: Welcome to the Forum.

I think you will find everyone will go with the 3 panels for the reasons 220/221 noted.
Unless you have a extremely large single load, the 3 panels will give you more versility as well as be easier and probably less expensive.

 

[iwire]

My first instinct is to go with 3 main breakered panels.

Mine to, assuming that you do not need to have any feeders larger then 100 amps from any of these panels.

Even if it did, there would be no easy way to kill all power without going outside or opening 3 separate panels and throwing the breakers. Seems like a potentially unsafe situation.

The NEC allows at least 6 service disconnects and more if you have fire pumps or other specific items.

I see no safety issue at all.

 

[Rep]

Fifth, welcome to the zoo! :smile:

Rep, how many circuits of each ampacity are we talking about?

About 60 - 70 total, mostly single phase 20 amp. A handfull of 20/30 2 phase and a few beasty 40 amp 3 phase. The owner (me) wants some room for expansion as I plan on building an addition about 65 feet away on the end of the building.

 

[Rep]

Rep: Welcome to the Forum

Thank you - glad I found such a knowledgeable and warm group of experts.

I think you will find everyone will go with the 3 panels for the reasons 220/221 noted.
Unless you have a extremely large single load, the 3 panels will give you more versility as well as be easier and probably less expensive.

I am reluctantly inclined to agree. After talking with my EC wholesaler, 3x 200 amp 3 phase main panels seem to be quite a bit more reasonable cost wise and since I have no loads over 50 amps, it seems like the best way to handle it.

 

[Rep]

Now the only question is how much planning should be done for future service? I know I can't locate the third box 65' away. Can I even pull a 65' 200 amp 3 phase line in a conduit and drop a subpanel there? The PoCo doesn't want to oversize for future growth or run a separate underground line a few months later even if I plan on starting work as soon as this building is done. It's never easy is it?

 

[LarryFine]

. . . there would be no easy way to kill all power without ... opening 3 separate panels and throwing the breakers. Seems like a potentially unsafe situation.

On the contrary, you'd have the versatility of not losing the entire service if you need to deenergize a panel, or a main trips.

About 60 - 70 total, mostly single phase 20 amp. A handfull of 20/30 2 phase and a few beasty 40 amp 3 phase. The owner (me) wants some room for expansion as I plan on building an addition about 65 feet away on the end of the building.

All the more reason for going with multiple panels, and maybe even add a sub for the addition later on.

 

[220/221]

glad I found such a knowledgeable and warm group of experts.

Stick around for the real story :grin:

 

[iwire]

Stick around for the real story :grin:

Quiet down, we have him fooled.

 

[LarryFine]

glad I found such a knowledgeable and warm group of experts.

Stick around for the real story :grin:

Shh! He thinks we're experts.



Or, what Bob said. :smile:

 

[Rep]

Posts: 30,501
Posts: 12,525

So you guys just pretend to be experts then?

The only problem I have with putting a sub meter in the expansion is the expansion is bigger sq footage wise than the original building! Seems... illogical to have a 200 amp sub panel... off a empty 200 amp main breaker panel.

 

[PetrosA]

Posts: 30,501
Posts: 12,525

So you guys just pretend to be experts then?

The only problem I have with putting a sub meter in the expansion is the expansion is bigger sq footage wise than the original building! Seems... illogical to have a 200 amp sub panel... off a empty 200 amp main breaker panel.

All you'd need at the trough is a 200A disconnect to feed the subpanel, which would be main lug, not main breaker. If you think you'll need more than one sub panel, you could always add a fourth panel at the trough (400A main lug, for instance) with room for three mains, then feed out of that to your subpanels. It would look better than separate disconnects.

As far as disconnecting all the panels at once in an emergency, the fire company would just pull the disconnect at the pole or at the transformer in a case like that. I think that's pretty standard operating procedure when they see CTs anyway.

 

[LarryFine]

Posts: 30,501
Posts: 12,525

So you guys just pretend to be experts then?

Yeah, but we did stay at Holiday Inns last night.

The only problem I have with putting a sub meter in the expansion is the expansion is bigger sq footage wise than the original building! Seems... illogical to have a 200 amp sub panel... off a empty 200 amp main breaker panel.

Well, you hadn't told us that part before. wink

In that case, make one of the three panels a main disco only, and reserve it for future use. If the addition will be that big, reserve two 200's.

 

[mivey]

Yeah, but we did stay at Holiday Inns last night.

Well there's the problem: it should have been a Holiday Inn Express :smile:

 

[iwire]

In that case, make one of the three panels a main disco only, and reserve it for future use. If the addition will be that big, reserve two 200's.

Sounds safe, NEC compliant and very money wise to me. :smile:

 

[Rep]

Great. We are going to go with 2x 200 amp main breakers, 1x main disconnect feeding a remote main lug.

Much cheaper to do it this way over 1 huge single panel. Plus, it meets code and appears to be SOP.

 

[LarryFine]

Well there's the problem: it should have been a Holiday Inn Express :smile: