Condo house panel & "supplied by one service" issue

[donw]

I have a condo project that has a building divided into 10 "modules" comprised of 3 units each. The modules are separated by block walls, and each module will have a meter pack serving its three units. So each module is a "building" served by one service entrance. My problem is that I'd like to have only one house panel for common lighting, etc. This lighting consists of lights for the common garages (each built under two units), a hallway between each garage and a unit, and three exterior wall-mounted lights. The exterior walls are framed - not block - and some of these lights are on them. Do I have to have ten house panels to satisfy the "building served by one service" rule? Should I go to a single main breaker SES with meter packs fed by it? How do you do that? I am used to doing commercial jobs and haven't worked much with residential modular metering much.
Thanks.

 

[hmspe]

"It depends..." A bit more information is needed. What is the calculated load for a typical unit panel? How did you do the load calcs? Can you use 220.84? Is the building being supplied single phase or three phase?

With "three pack" metering as you describe IMO you can't have a single house panel unless the exterior equipment is all surface mounted. If you're treating each section of the structure as a separate building then you can't cross circuits between buildings. Where I live surface mounted equipment is considered "outside the building" so we're not serving the building when we feed the surface mounted stuff. That gets us around the multiple services supplying a building problem. YMMV.

What you may be able to do is use NEC 230.2(C)(2). Just because there are fire walls does not mean you can't treat this as a single building. In this area the largest standard size 120/240 single phase servide is 800A. Depending on how the load calcs are done you might be able to "legally" use 3 or 4 services for the building as a whole, and a single service for all the house loads would be acceptable. There's nothing in Code that says that if there are multiple services under 230.2(C)(2) that the services have to be located together. I typically see a 12-pack on each end of a 24 unit building.

Martin

 

[donw]

hmspe, thanks. It is single phase, and I haven't done any calcs yet. I do plan on using 220.84. I think you're right. I'd have to come over 800 amps here, too. By surface mount, do you mean that the conductors have to be surface - not in the wall - or that the fixture has to be surface?

 

[mc5w]

Condo House Panel

Condo House Panel

You could also use 2 other rules which are the large area building rule and the different purpose rule.

However, I do not see how the garages are common areas. These should be fed from each unit. If you decide to run the garages off of the house panel each garage needs a separate subpanel to meet local disconnection rules and to meet access to overcurrent device rules.

 

[donw]

Thanks, mc5w. What code sections are those two rules found?
The "garages" are really open carports with condo units over them. One of the four carports per module is designated "guest", so it seems that it should remain lit even if one of the unit's power is turned off.