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Explain "instantaneous override" and "close and latch" ratings.

Explain "instantaneous override" and "close and latch" ratings. What do they mean?

Product Line:
Circuit Breakers

Masterpact and Powerpact

"Instantaneous override" and "close and latch" are fixed trip settings to protect the breaker when there is a very hight fault condition.  These settings are usually set higher than the standard instantaneous setting and function without regard to any other settings.

"Instantaneous override" is a fixed trip setting to open the breaker quickly (under 25mS) in the event of very large fault which exceeds the instantaneous override trip value.

"Close and latch"  is a fixed trip setting while CLOSING the breaker and remains in effect for 20mS after closing the breaker.  Close and latch is set lower than instantaneous override, to protect the breaker in the event of CLOSING the breaker on an existing fault condition.   After 20mS the breakers reverts to the "instantaneous override" setting.
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