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#86048 - 09/03/03 07:59 AM Circuit Breakers
boxford Offline

Registered: 03/10/03
Posts: 15
Loc: St. Paul, MN, USA
What article in the NEC states that you can only utilize a circuit breaker up to 80% of its capacity?

2014 / 2011 NEC & Related Books and Study Guides
#86049 - 09/03/03 08:33 AM Re: Circuit Breakers
Ron Offline

Registered: 03/13/02
Posts: 577
Loc: White Plains, NY
210.19(A)(1) & 215.3 provide limits for overcurrent protection of continuous loads

#86050 - 09/04/03 06:41 AM Re: Circuit Breakers
dana1028 Offline

Registered: 01/09/02
Posts: 163
Loc: San Carlos, CA
(1999) 384-16(d) - Continuous Load
'The total load on any overcurrent device located in a panelboard shall not exceed 80% of its rating where, in normal operation, the load will continue for 3 hrs. or more.'

(2002) - In 2002 this section was deleted.[Proposal 9-107, ROP] It was contended that rules in 210.19(A), 210.20(A), and 215.3 cover this issue and this wording was unnecessary.

#86051 - 09/04/03 09:46 AM Re: Circuit Breakers
boxford Offline

Registered: 03/10/03
Posts: 15
Loc: St. Paul, MN, USA
Thank you very much I really appreciate it.

#86052 - 09/12/03 05:35 AM Re: Circuit Breakers
jnsells Offline
Junior Member

Registered: 08/26/03
Posts: 2
Loc: Nashville, TN
Most small molded-case breakers are only rated for 80% of their nominal rating. Larger frame molded case breakers can be specified as "100% rated" but will cost more. Best to check with the manufacturer.


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