Applicability of ANSI C37.010

[kartracer087]

Does ANSI C37.010 emergency ratings definitions also apply to medium voltage (5-35kV) drawout circuit breakers? For example, say you have a substation with 84MVA transformers and you have an emergency 4-hour rating of 100MVA on a bus section. At 24.9kV, you would be over a 2000A breaker rating, so for that condition, could you in effect apply the provisions of C37.010 for that special case of a temporary overload?

Thanks,

 

[kartracer087]

Nevermind, I found that the C37.010 standard for emergency ratings does not apply to metal-clad breakers. So I guess it would be more of a question for the manufacturer. I think in my application above realistically you would need to apply a 3000A breaker in metalclad gear. Interestingly enough, most metal clad manufacturers do not offer 3000A breakers in 27kV construction, typically you would need to go with a 38kV unit. They are much larger and the structures are also much larger.