110.26(C)(2) Working Spaces & Large Equipment

[ElectrifiedClimber]

Hello All, I have a code interpretation question that I am curious for your thoughts on. Working with NEC 2023 and the updated 110.26(C)(2) verbiage.

110.26(C)(2) requires large equipment to have means of egress at each end of the working space. This requirement shall apply to either:
(1) For equipment rated 1200A or more and over 1.8m (6ft) wide.
(2) For service disconnecting means installed in accordance with 230.71(b) where the combined ampere rating is 1200A or more and where the combined width is over 1.8m (6ft).

I am working on a new outpatient clinic with a tier 2 EES that has a 1000A, 208Y/120V MDP, and 400A, 208Y/120V EDP feeding and EQ and LS ATS' in the main electrical room. Both MDP and EDP are fed from MV XFMRs outside off of campus medium voltage loops. Would the EDP MCB also be considered a service disconnecting means coming from the medium voltage transformer outside? My gut say no since it's part of the emergency system and not disconnect all conductors coming into the building.

If both are considered service disconnects, the question is then: Our MDP is (2) section switchboard. A 30" 1000A individually mounted breaker section (service disconnect) and a 36" distribution section. Total width is 66". The EDP is 31.5" wide with a 400A MCB. If we need to determine the combined width of the service disconnect means width, do we have to take the total width of the switchboard and add it to the width of the EDP (31.5") = 97.5"? Or can we use just the width of the individually mounted breaker section (30") and EDP for a total width of (61.5")?

Much appreciated,

Andrew

 

[ron]

If the meter / service drop is at the medium voltage level (MV service disconnect), then anything downstream will not be a service disconnect. A generator feeder is only a feeder, not a service disconnect.

A service is defined in Article 100 as "The conductors and equipment connecting the serving utility to the wiring system of the premises served." You are downstream of that.

 

[ElectrifiedClimber]

This is a new stand-alone building on an existing campus. The campus has two sets of switchgear on either side from the utility where it is metered and feed the loop. The building itself is not metered but does have its own MV XFMR feeding the building, so I was anticipating the MDP MCB being a service disconnect for the building, but I missed the key part about connecting to the "serving utility".

The emergency side also makes sense. The whole campus is backed by parallel generators stepped up to a MV loop and the MV XFMR step down feeding the emergency side is something I hadn't run into before. I am used to MV XFMRS being part of the utility system, so I was second guessing that aspect.

Much appreciated!