Lighting Circuits shared between Apartments

[Beth]

Working on new senior apartment building in California. The apartments will not have their own panels, they will be circuited from shared panels in the main closet or panels in the hallways. The circuits for power will be dedicated to the individual apartments, but I would like to share the lighting circuits between a couple of apartments. The fixtures will be LED, so the loads will not be high. Does the NEC allow the lighting circuits to be shared between different family dwellings?

 

[iwire]

I don't believe you can do that.

210.25 Branch Circuits in Buildings with More Than
One Occupancy.

(A) Dwelling Unit Branch Circuits. Branch circuits in
each dwelling unit shall supply only loads within that dwelling
unit or loads associated only with that dwelling unit

The doubt I have comes from not knowing if each unit truly is a dwelling unit or is the kitchen in a central area.

 

[charlie b]

I was about to type in a similar reply, with the same question in my mind: Do these apartments fall within the NEC definition of "dwelling unit"?

But regardless of whether this is or is not allowed by the NEC, I don't think it is a good idea. It is not a matter of total load on each circuit. It is a matter of one person doing something to a light fixture in their apartment, and having a spark trip the breaker, thus turning off lights in another apartment. It's not a good design.

Let me also mention that the building has to be under continuous management, or else you have to give each unit its own panel. My interpretation is that you have to have an owner or a hired manager on the premises 24/7/365. I think it is OK if the manager sleeps in the building. That is, you don't need someone awake and at the desk at all times. But if a resident has a breaker trip and does not have ready access to the panel, they need to be able to call the manager (wake the person up, if need be), and have the manager reset the breaker. Reference 240.24(B)(2).

 

[Beth]

Microwave and Refrigerator only

Microwave and Refrigerator only

Thanks for reply. 210.25(A) seems to say that if the circuits originate from one dwelling, they can not be shared with another. The panels will not be inside the individual apartments. I can not find anything in the NEC or on the web that clearly says you can not share the lighting circuits, but nothing seems to say you can either.

 

[iwire]

Thanks for reply. 210.25(A) seems to say that if the circuits originate from one dwelling, they can not be shared with another.

I see nothing that mentions where they originate.

You might want to run it by the AHJ before you get too far.

 

[Beth]

Its a senior apartment bldg, so will have 24/7 staff.

Its a senior apartment bldg, so will have 24/7 staff.

I was about to type in a similar reply, with the same question in my mind: Do these apartments fall within the NEC definition of "dwelling unit"?

But regardless of whether this is or is not allowed by the NEC, I don't think it is a good idea. It is not a matter of total load on each circuit. It is a matter of one person doing something to a light fixture in their apartment, and having a spark trip the breaker, thus turning off lights in another apartment. It's not a good design.

Let me also mention that the building has to be under continuous management, or else you have to give each unit its own panel. My interpretation is that you have to have an owner or a hired manager on the premises 24/7/365. I think it is OK if the manager sleeps in the building. That is, you don't need someone awake and at the desk at all times. But if a resident has a breaker trip and does not have ready access to the panel, they need to be able to call the manager (wake the person up, if need be), and have the manager reset the breaker. Reference 240.24(B)(2).

I do see your point, and agree its not a good idea. Thank-you.

 

[charlie b]

Thanks for reply. 210.25(A) seems to say that if the circuits originate from one dwelling, they can not be shared with another.

I see nothing that mentions where they originate.

I had thought about this question. What does the word "in" mean? The code says that a branch circuit that is IN one unit can only supply loads in that unit. Is a branch circuit only in a unit when every part of the circuit, from breaker to load, is within the walls of that unit? Or if part of a branch circuit, specifically some of the wires and all of the loads, is within the walls of the unit, but another part of the circuit, specifically the breaker and some of the wires, are outside the wall, is that circuit covered by 210.25(A) or not? My take is that the code forbids having loads in two different occupancies on the same circuit. But I do see room in the wording of the code for disagreements on that interpretation.

I remember a relevant debate from several years ago on this forum. At issue was the wall between two units in an apartment building. There will likely be receptacle outlets on both sides of that wall. Which unit are those circuits in? Can you even put wires in the wall that separates two units, without violating 210.25(A)? I think the original question from that debate had to do with running a wire from a house panel in the basement to a house load in the attic, but passing the wire through the wall that separates two units on the first floor. What I don't remember is how that debate turned out.