Grouping of dwelling unit feeders

[AM59]

I have an existing large multifamily residential building that has the dwelling units fed via a busway riser with a disconnect on each floor feeding group-mounted meters (with feeder breakers) feeding the individual dwelling units on every floor. However, due to renovations and reconfiguration, the plan is to have more dwelling units (due to dividing up dwelling unit space, etc) on each floor than can be fed from the existing busway and metering configuration.

We will need to add an additional service from the utility regardless to handle this new load, but that part is handled. The issue is where we can put the additional meters and feeder breakers.

What I had proposed was feeding units from other floors in a cascading pattern, so that the new meters and breakers would be located in the basement (at the new service) and have the feeder runs from this equipment be as short as possible, only feeding units on the 1st and 2nd floors. The inspector said that this was not a code compliant solution, since residential units on the upper floors would not have all unit feeders located in a predictable location. I argued that we have had buildings with multiple residential meter lineups per floor, buildings with all residential meters in the basement/outside, and buildings with meters on every other floor; never had any issue like this with those. Has anybody run into a requirement like this before, and/or know what code requirement he is basing this on? We unfortunately did not have a code book in the meeting so he only gave me general sections, Article 220, 230, and 255. I'm hoping I just misrecorded those.

 

[electrofelon]

. The inspector said that this was not a code compliant solution, since residential units on the upper floors would not have all unit feeders located in a predictable location. .

The inspector needs to provide a code reference (which he will not be able to find) rather than spewing out nonsense.

 

[tortuga]

This kinda thing is where using correct code terms for conductors is important, 'service' and 'feeder' have important distinctions (Article 215 vs 230) and NEC definitions.
Set aside what the utility calls a 'service'. There is no NEC code on what conductors a utility is metering, a utility can meter service or feeder conductors, the utility will have their own guidelines you'll also need to consider.

I have an existing large multifamily residential building that has the dwelling units fed via a busway riser

Is the busway riser service conductors or feeder conductors?

 

[Elect117]

I would send him the following code sections.

230.2(E) - Identifying services where more than one feeds a single building.

225.37 - Identifying all services, feeders, and branch circuits feeding a structure (typically used were multiple feeders feed an additional structure).

There was also some code changes to the style of multimeter gears. Where the service disconnects need to be isolated from other service disconnects. 230.71(B) Maybe that was the issue?

 

[electrofelon]

One other section that could possibly apply is 240.24 B. However access is pretty easy to provide, and typically larger buildings would fall under the continuous building management supervision exception anyway.