MCC Has 4 Wire loads, but no neutral bussing in sections with 4W loads

[Scafremon]

I have purchased a new MCC. Plans call for 480Y/277 3P4W MCC, which makes sense, as in addition to the many 3W loads, there are a few 4W loads throughout the lineup. It is being fed from a swbd with 4 wires. It is not service entrance.

The manufacturer has advised that they are only providing a neutral bus in the incoming section - not a full length neutral bus as I was expecting.
For the loads that have 4 wires, the mfg advises that the contractor can run his neutral wire through multiple vertical sections over to the incoming section where the neutral pad is located, and terminate his neutral there. This appears to comply with 430.97 (A), based on the exception, as long as the barrier requirement is met. But I am still concerned if there might be some other code violation.

Once concern is section labeling. I would think that any section that does not have a neutral bus located within it will have to be labeled as 3P3W. We will therefore have disconnects for 4 wire loads located in vertical structures labeled as 3P3W.

Do you see any code concerns?

 

[MattS87]

Are you talking about a typical MCC with multiple buckets for motor starters? I can't say that I have ever seen one with a neutral bus. What types of loads do you have that require the neutral? If they are lighting and such, you could order a 480/277V panelboard factory installed

 

[Jraef]

...
Once concern is section labeling. I would think that any section that does not have a neutral bus located within it will have to be labeled as 3P3W. We will therefore have disconnects for 4 wire loads located in vertical structures labeled as 3P3W.

No. The labeling on an MCC is not required to show the "number of wires" at all. Some do, some don't. But if they HAVE a neutral bus, that must be identified on the section label with its ampacity, but only for the sections that have it.

Do you see any code concerns?

No, it's done all the time. It's expensive to run that full sized Neutral bus down the entire length of an MCC just to feed a few loads. What I do is that I arrange the units so that anything needing the Neutral connection is in or next to the section that has the bus.

 

[csc_wyo]

The manufacturer has advised that they are only providing a neutral bus in the incoming section...Do you see any code concerns?

I ran into this for the first time this year as well and had the same concerns. This is becoming a new "norm" for MCC's and the requirement to run a neutral cable back to the neutral block in the incoming section. There isn't any code violation(s) and it doesn't violate UL 845 (such that you utilize the wire way). As previously mentioned, if possible, try and arrange your 4-wire loads near the incoming section for termination to shorten the amount of wire way fill and installation time.