SEC sizing

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badjeepr

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I am attempting to size SE conductors per 220.87. It would appear that to do this the combined ratings of my 6 service disconnects could not exceed the rating of the SE per 230.90. Can i use 230.90 ex. no. 3 to get around this, considering my "calculated load" to be the (max demand over a 1 yr period@ 125%)+ new load? 220.87(3) refers me to 230.90 for service overcurrent protection. Seem to be going in circles
 
show your faces

show your faces

OK...who were the other 15 persons that viewed this post and didnt offer any guidance?
 
badjeepr said:
I am attempting to size SE conductors per 220.87. It would appear that to do this the combined ratings of my 6 service disconnects could not exceed the rating of the SE per 230.90. Can i use 230.90 ex. no. 3 to get around this, considering my "calculated load" to be the (max demand over a 1 yr period@ 125%)+ new load? 220.87(3) refers me to 230.90 for service overcurrent protection. Seem to be going in circles
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230.90(A) Exception 3, is there exactly for the scenario you appear to have.

Going in circles is eliminated if your SE has an ampcity equal to or greater than the calculated load... in this case: 125% of exisitng demand plus the new load.
 
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