Multi-tenant commercial space panel requirements

[Floyd R Turbo]

I'm having a little trouble finding an answer in the NEC to this question:

Let's say that I have a commercial space, such as a ground floor of a high rise apartment building. This space currently has a single 480V panel and is all open space (no dividing walls)

The space now needs to be divided into more than one commercial tenant space: A, B and C.

The 480V panel would be in a dedicated electrical room in the "A" space. This space would not necessarily be readily accessible to the "B" and "C" tenants at all times (i.e., if tenant "A" was closed)

Each space will have 480V loads (HVAC - compressors on roof and air handling units in the tenant space, both with fused disconnects) and 120V loads (lighting & receptacles).

Do the "B" and "C" spaces need to have their own 480V sub-panel for the 480 loads that serve those spaces, or can the 480V loads from all 3 spaces be served from the existing 480V panel in the "A" space?

Similarly, each space would have 120 loads, and these would be done via separate transformers (one for each space). If all 480V loads can be served from the "A" space closet, can all three 480/208 transformers be located in that closet as well, with 120/208 sub-panels then in each tenant space?

I guess this boils down to the question of, for a subdivided commercial/retail space that is leased, does it matter where the circuit breakers are that serve that space?

 

[Dennis Alwon]

See if art. 240.24(B) answers your question

 

[Floyd R Turbo]

Thank you that is, I believe, what I was looking for

I think the building in this example by definition is multiple occupancy (apartments above, businesses on the ground floor)

But I guess, for this particular example, it depends on what the term "occupancy" applies to. Would one consider spaces A B and C to be separate occupancies? i.e. separate leased spaces, that are lockable by the renter of the space? If occupancy in this case is the classification of the use of the space, like clothing retailer vs coffee shop vs a business office vs a bar/brewpub/nightclub...then the 240.24.B.1 would seem to answer my question

 

[Smart $]

Thank you that is, I believe, what I was looking for

I think the building in this example by definition is multiple occupancy (apartments above, businesses on the ground floor)

But I guess, for this particular example, it depends on what the term "occupancy" applies to. Would one consider spaces A B and C to be separate occupancies? i.e. separate leased spaces, that are lockable by the renter of the space? If occupancy in this case is the classification of the use of the space, like clothing retailer vs coffee shop vs a business office vs a bar/brewpub/nightclub...then the 240.24.B.1 would seem to answer my question

Please note the requirement text says "each occupant". If occupant "B" cannot access the supply ocpd(s) to occupancy "B", that would be non-compliant.

 

[Floyd R Turbo]

240.24.B.1 says

Where electric service and electrical maintenance are provided by the building management and where these are under continuous building management supervision, the service overcurrent devices and feeder overcurrent devices supplying more than one occupancy shall be permitted to be accessible only to authorized management personnel in the following: 1) Multiple-occupancy buildings 2) Guest rooms or guest suites

So if the building has continuous supervision and B.1 applies, then this

Please note the requirement text says "each occupant". If occupant "B" cannot access the supply ocpd(s) to occupancy "B", that would be non-compliant.

Isn't applicable.

Now my question is what technically does "continuous supervision" mean. One could argue this means full time on-site staff, that would obviously be true. But what about on-call services during evenings & weekends? I would think that there are many such multi-occupancy buildings in large cities where the tenants (be they for commercial spaces or dwelling units) don't have direct access to ocpds all the time but have on call services...

 

[Floyd R Turbo]

http://forums.mikeholt.com/showthread.php?t=77443