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Existing Load Calculation and Added Load - Industrial

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S

scrub12

Member
Location
Cleveland, OH
Occupation
Electrical Engineer
I have a 1600A main breaker. I've compiled load data for the last year to get a peak load. I am adding load to this existing service but want to ensure the breaker is sized appropriately. Utilizing NEC, Article 220.87 states, "The maximum demand at 125% plus the new load does not exceed the ampacity of the feeder or rating of the service." The 1600A breaker is 80% rated. Do I need to add 25% to the new load (Continuous Load) or is it permitted just to utilize 125% of the existing load plus the new connected load at 100%?
 
E

Elect117

Senior Member
Location
California
Occupation
Engineer E.E. P.E.
the new load would include any increases based on continuous ratings.

For example:

100KVA existing

I want to add 100KVA of continuous load and 50kVA of non continuous load,

New total load = existing * 1.25 + new continuous *1.25 + new non continuous
 
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