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What is the difference between a 80% rated breaker and a 100% rated breaker?
Issue:
What is the difference between a 80% rated breaker and a 100% rated breaker?
Do we have a list of 100% rated circuit breakers?
Resolution:
For a particular breaker, even though the 80% and 100% versions have the same amp rating (use the same trip curve), in actual use they are applied differently depending on the continuous loads (amount and length of time).
The 80% (standard-rated) breaker can only be applied continuously (defined as 3 hours or more by the NEC) at 80% of its continuous current rating (or Ir setting; e.g. if a 150 A H-frame is dialed to 100 A, the 80% rating applies to the 100 A setting). 100% rated circuit breakers can be applied at up to 100% of their current rating continuously. Breakers rated at 80% can be applied at 100% of their rating if the loading will last for less than 3 hours.
The following frames have versions that can be 100% rated:
- Powerpact H frame: unit mounted only, with special suffix
- Powerpact J frame: unit mounted only, with special suffix
- Powerpact L frame: Unit mounted or ILINE up to 400 amps, with special suffix
- Powerpact P and R frame, with special suffix
- Masterpact NT and NW
For further information, see the attached link:
http://blog.schneider-electric.com/datacenter/power-and-cooling/2014/06/12/clearing-confusion-80-vs-100-rated-circuit-breakers/