Article 225.30

[RAKocher]

My employer has a large commercial property with several buildings and just had a, less than 3000 sq ft, temporary structure built (5 trailers fastened together). Two 208/120v 3p 4w w/g feeders were installed from a nearby bldg and both are supplied from breakers in the same panel. Feeder A terminates in a MBP, feeder B terminates in an ATS and both are mounted on the outside of the new structure. An outdoor generator provides the auxiliary power to the ATS, and the ATS feeds a MBP that’s also mounted on the outside of the new structure.

Is feeder B article 225.30(A)(2) Emergency system’s additional feeder that is permitted?

 

[jumper]

My employer has a large commercial property with several buildings and just had a, less than 3000 sq ft, temporary structure built (5 trailers fastened together). Two 208/120v 3p 4w w/g feeders were installed from a nearby bldg and both are supplied from breakers in the same panel. Feeder A terminates in a MBP, feeder B terminates in an ATS and both are mounted on the outside of the new structure. An outdoor generator provides the auxiliary power to the ATS, and the ATS feeds a MBP that’s also mounted on the outside of the new structure.

Is feeder B article 225.30(A)(2) Emergency system’s additional feeder that is permitted?

I doubt it qualifies as an Emergency System.

700.2 Definitions.
Emergency Systems.
Those systems legally required and
classed as emergency by municipal, state, federal, or other
codes, or by any governmental agency having jurisdiction.
These systems are intended to automatically supply illumi-
nation, power, or both, to designated areas and equipment
in the event of failure of the normal supply or in the event
of accident to elements of a system intended to supply,
distribute, and control power and illumination essential for
safety to human life.

If anything it would be an Optional Standby (Article 702), and with 2 feeders plus the genny backing up one I am not sure of even this is correct.

I am more used to one feeder, ATS, and genny. I am not sure 225.30 is gonna allow your set up.

 

[Smart $]

I agree with Derek. The feeder from the generator is what's covered by 250.30(A)(2), not Feeder B.

That said, the AHJ may have granted permission to do it this way under 250.30(B)(2).

 

[RAKocher]

That said, the AHJ may have granted permission to do it this way under 250.30(B)(2).

I guess that's what happened.

What I described is now complete and inspected. I wasn't involved in the project, but a GC an EE and an EC were. The structure is considered temporary and the source panel is a 35 yr old 1200a GTE/Sylvania and the breakers used were existing (neither large enough for the full load), so maybe all things considered some leniency was given.

Thanks for your quick replies.