NEC 240.24(B) Location in or on Premises.

[electricalintern]

If there are 3 Tenants (A, B and C) in one building. The main electrical service is going to be located in Tenant A space.

Is it possible to place the main electrical service in Tenant A's space without the need to construct an electrical closet?

 

[coop3339]

Maybe consider outdoor rated equipment mounted on the outside wall. That way all tenants would have access to their breakers. It will be a more expensive to buy the equipment but would solve the issue.

 

[electricalintern]

The owner decided to built a Electrical Closet for the service now.
But if the electrical closet is in the rear of the building, do they need a door that opens directly from the outside to access the electrical closest or can it be accessible thru Tenant A's space.

 

[charlie b]

Each tenant must have access to the circuit breakers serving loads in their space. That is usually done by putting a panel in each space. Where the upstream equipment (i.e., main panel) is located is not relevant. It can be in one tenant space; it need not be accessible only from outside.

 

[don_resqcapt19]

Each tenant must have access to the circuit breakers serving loads in their space. That is usually done by putting a panel in each space. Where the upstream equipment (i.e., main panel) is located is not relevant. It can be in one tenant space; it need not be accessible only from outside.

In my opinion the rule in 240.24(B)(1) would almost always require that the tenant have access to the service of main breaker that supplies their unit. It is unlikely that in a 3 unit building that the main breakers for each unit "are under continuous building management supervision". If they are not "are under continuous building management supervision" the tenant must have access to that main breaker.

 

[electrofelon]

In my opinion the rule in 240.24(B)(1) would almost always require that the tenant have access to the service of main breaker that supplies their unit. It is unlikely that in a 3 unit building that the main breakers for each unit "are under continuous building management supervision". If they are not "are under continuous building management supervision" the tenant must have access to that main breaker.

I agree "upstream" breakers are also covered by the access requirement, they certainly serve the tenant space. That said, I have typically seen the access rule interpreted a bit more loosely to be more like "as long as someone is a phone call away".

 

[augie47]

230.72(C) seems to address it fairly well.
(C) Access to Occupants. In a multiple-occupancy building, each occupant shall have access to the occupant’s service disconnecting means.

Exception: In a multiple-occupancy building where electric service and electrical maintenance are provided by the building management and where these are under continuous building management supervision, the service disconnecting means supplying more than one occupancy shall be permitted to be accessible to authorized management personnel only.

 

[charlie b]

230.72(C) seems to address it fairly well.
(C) Access to Occupants. In a multiple-occupancy building, each occupant shall have access to the occupant’s service disconnecting means.

Cannot that be the main breaker in each tenant's panel?

Let's expand the situation to a multi-story apartment building. The building's service equipment is in a locked room in the basement. Each floor has an electric room with a distribution panel (DP) that serves only that floor. Each DP has breakers that serve the main breaker branch panel in each apartment (no MLO in this building, if you please).

My opinion is that each tenant is NOT required to have access to the breaker in the DP on their floor that serves their panel (and certainly not the breaker in the main electric room that feeds their floor's DP). Indeed, if something in a tenant's panel causes the upstream DP breaker to trip, I believe it should take more than "building management supervision" to determine whether it will be safe to turn it back on. So I interpret "occupant's service disconnecting means" as referring to each tenant's panel's main breaker.

Please note that the word choice in this code article is sloppy, at best. By the time you get down to the tenant's power system, you are no longer dealing with "service equipment."

 

[augie47]

At times I get in trouble for taking the Code too literally but the definition of "Service" is pretty clear and 230.72 applies to services.
Unless the tenants panel is supplied directly from the POCO source it is not a service panel and, based on 230,72, unless one of the exceptions applies I think they need access.


(Your multi-story apartment building would likely meet the exception)

 

[electrofelon]

. So I interpret "occupant's service disconnecting means" as referring to each tenant's panel's main breaker.

Please note that the word choice in this code article is sloppy, at best. By the time you get down to the tenant's power system, you are no longer dealing with "service equipment."

Charlie, come on, a service disconnect is a very specific thing. You can't call anything you want a service disconnect.

 

[charlie b]

I acknowledge that 230 is all about services, and that requires me to revise my argument. That is my way of saying, "mea culpa" (Latin for "my bad").

I believe that 230.72(C) is addressing the situation in which our three tenants are each supplied directly from the utility. Each must have access to their own service disconnecting means. But that is not the present situation. The tenants are not getting service from the utility; only the building gets service from the utility. Our tenants have feeders to their panels. Therefore, 230.anything does not apply. Bottom line: the location of the building's service equipment is irrelevant, and the answer to the original question is yes.

 

[don_resqcapt19]

Cannot that be the main breaker in each tenant's panel?

Let's expand the situation to a multi-story apartment building. The building's service equipment is in a locked room in the basement. Each floor has an electric room with a distribution panel (DP) that serves only that floor. Each DP has breakers that serve the main breaker branch panel in each apartment (no MLO in this building, if you please).

My opinion is that each tenant is NOT required to have access to the breaker in the DP on their floor that serves their panel (and certainly not the breaker in the main electric room that feeds their floor's DP). Indeed, if something in a tenant's panel causes the upstream DP breaker to trip, I believe it should take more than "building management supervision" to determine whether it will be safe to turn it back on. So I interpret "occupant's service disconnecting means" as referring to each tenant's panel's main breaker.

Please note that the word choice in this code article is sloppy, at best. By the time you get down to the tenant's power system, you are no longer dealing with "service equipment."

That building would be much more likely to comply with "electric service and electrical maintenance are provided by the building management and where these are under continuous building management supervision," than the 3 unit building in this thread.

 

[electricalintern]

Each tenant must have access to the circuit breakers serving loads in their space. That is usually done by putting a panel in each space. Where the upstream equipment (i.e., main panel) is located is not relevant. It can be in one tenant space; it need not be accessible only from outside.

So if each Tenant has their own Panels with a Main Breaker, this will pass code regardless if the main service is being feed from Tenant A space.

Then would you still need a electrical closet if each tenant has a Main Breaker in their space?

 

[charlie b]

Having rethought this issue, I will now say that you don't even need each tenant's panel to have its own main breaker. I would include one anyway, for the convenience of future work on the panel, but code will allow an MLO fed from the upstream service equipment. It does not matter where that service equipment is located, and the tenants are not required to have access to it.

Now let's talk logistics. I believe putting the service equipment in a room accessible only from the outside is a far better design. That is because if tenant B's panel needs an upgrade or other significant work, and if the service equipment is in tenant A's space, the work will be an inconvenience to tenant A. How important is that? Only the building's owner can answer that question.

 

[charlie b]

That building would be much more likely to comply with "electric service and electrical maintenance are provided by the building management and where these are under continuous building management supervision," than the 3 unit building in this thread.

Another member made the same observation to me in a PM. My response is that it is likely to be true, but that is not relevant to the issue under discussion. Put a panel in each tenant's space and you will fulfill the requirement to give each tenant access to the overcurrent protection devices that serve loads in their space. Where those panels get their power does not alter that requirement, nor does it impact compliance with that requirement.

 

[electricalintern]

Having rethought this issue, I will now say that you don't even need each tenant's panel to have its own main breaker. I would include one anyway, for the convenience of future work on the panel, but code will allow an MLO fed from the upstream service equipment. It does not matter where that service equipment is located, and the tenants are not required to have access to it.

Now let's talk logistics. I believe putting the service equipment in a room accessible only from the outside is a far better design. That is because if tenant B's panel needs an upgrade or other significant work, and if the service equipment is in tenant A's space, the work will be an inconvenience to tenant A. How important is that? Only the building's owner can answer that question.

Sorry but I'm a little unclear why you changed your mind and a MCB is no longer needed.
How does the tenant have access to their OCPD?

I will still show each tenant have a MCB but I was just wondering why we don't need access to Tenant A space.

So if Tenant A has the main disconnect in their space and each tenant has their own MCP on their Panel, does that meet code with "a phone call away"

Here is what I have for my riser diagram so far

 

[don_resqcapt19]

Another member made the same observation to me in a PM. My response is that it is likely to be true, but that is not relevant to the issue under discussion. Put a panel in each tenant's space and you will fulfill the requirement to give each tenant access to the overcurrent protection devices that serve loads in their space. Where those panels get their power does not alter that requirement, nor does it impact compliance with that requirement.

The would be correct if the code said that, but it doesn't.

240.24 ... (B)Each occupant shall have ready access to all overcurrent devices protecting the conductors supplying that occupancy, ...

The feeder conductors that supply the tenant panel, are conductors that supply that occupancy, and the tenant must have access to the feeder OCPD.

 

[charlie b]

I read that differently, Don. To my way of thinking, the "conductors supplying that occupancy" originate at the breakers within the tenant's panel. The upstream breaker protects the feeder to the panel, not the conductors inside the tenant's space. Specifically, the 200 amp upstream feeder breaker does not provide overcurrent protection to the #12 THHN wires serving outlets in the tenant space.

Looking at this your way makes me wonder whether each tenant needs access to the service transformer's primary breaker. OK, nonsense aside, and more to the point, how far upstream does this access requirement go?

 

[don_resqcapt19]

I read that differently, Don. To my way of thinking, the "conductors supplying that occupancy" originate at the breakers within the tenant's panel. The upstream breaker protects the feeder to the panel, not the conductors inside the tenant's space. Specifically, the 200 amp upstream feeder breaker does not provide overcurrent protection to the #12 THHN wires serving outlets in the tenant space.

Looking at this your way makes me wonder whether each tenant needs access to the service transformer's primary breaker. OK, nonsense aside, and more to the point, how far upstream does this access requirement go?

The language needs work, but I think the tenant needs access to the feeder breaker that supplies his unit, unless there is the continuous supervision.

There is nothing that talks about supplying outlets...it only talks about supplying the occupancy and the feeder conductors do that. Maybe a PI is in order to make it say something like supplying outlets in place of the current language that says supplying the occupancy.

And yes, the current wording probably requires the tenant to have access all the way to the output OCPD on the utility generator that is supplying his unit. Again a PI could clear this up as there is no way that the intent goes beyond the feeder breaker that supplies the occupancy.

 

[charlie b]

Rephrasing something I mentioned earlier, I would not want the tenant to have the ability to reset the feeder breaker upstream of their panel. If that breaker tripped, something is significantly wrong, and the tenant is unlikely to be able to discern whether resetting the breaker is safe.

Moreover, while the tenant is in one location resetting the feeder breaker, they would not be able to observe any arcing and sparking that might be taking place at their panel right after the feeder breaker is reclosed. All I would want the "continuous building management supervision" (unlikely to be an electrician) to do in that event us to contact an electrician.