SERIES RATED

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D.MOON

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HUNTSVILLE, AL.
CAN CURRENT LIMITING FUSES BE USED AT THE PRIMARY SERVICE ENTRY FOR THE PURPOSE OF LIMITING FAULT CURRENT TO A LEVEL LESS THAN THE EXISTING FACILITIES EQUIPMENT'S AIC RATING, THEREBY REDERING WHAT WOULD OTHERWISE BE OVERDUTIED EQUIPMENT IN COMPLIANCE? IF THIS IS TRUE WOULD THERE BE A CONFLICT WITH 240.86 (B) OF THE NEC? IN OTHER WORDS WOULD THIS BE CONSIDERED AN ATTEMPT TO SERIES RATE PROTECTIVE DEVICES?
 
D.MOON said:
CAN CURRENT LIMITING FUSES BE USED AT THE PRIMARY SERVICE ENTRY FOR THE PURPOSE OF LIMITING FAULT CURRENT TO A LEVEL LESS THAN THE EXISTING FACILITIES EQUIPMENT'S AIC RATING, THEREBY REDERING WHAT WOULD OTHERWISE BE OVERDUTIED EQUIPMENT IN COMPLIANCE? IF THIS IS TRUE WOULD THERE BE A CONFLICT WITH 240.86 (B) OF THE NEC? IN OTHER WORDS WOULD THIS BE CONSIDERED AN ATTEMPT TO SERIES RATE PROTECTIVE DEVICES?
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To my knowledge the down stream devices must be series list for use with the fuses that you are thinking will work.
You must go back to the manufatures catalog for series rated devices and that should include a listing of fuses that their products would be series rated with.
In order be series rated the manufacturer must do short circuit testing with the fuses.
(Also, it looks as if your caps lock must be on.)
 
Most minature molded case breakers (i.e. those built to UL489) operate almost, but not quite, as fast as fuses. Because of this, the operation of their contacts introduces additional impedance into the circuit which messes up the current limiting function of the fuse. This is why breaker-fuse combinations must be 'tested'.

Power circuit breakers (usually drawout style), also called iron-frame or ANSI style, breakers without an instantaneous trip element are the ones that fuse manufacturer usually describe in their literature when mentioning field series-ratings.
 
.....typing in capital letters is a form of 'yelling' and makes your post harder to read.
 
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