What NEC rules apply specifically to overcurrent protection for underground medium-voltage service-entrance conductors (between the meter and the service disconnect)?
230.90(A) says "..protection shall be provided by an overcurrent device.. that has a rating no higher than the allowable ampacity of the conductor".
230.208 allows short circuit protection for the feeder supplied by the service disconnect, up to 3x the conductor ampacity. Would this rule also apply to service entrance conductors?
240.100 allows for protection to the thermal damage curve of the cable or, for feeders, up to 3x the conductor ampacity. Would this rule apply to service entrance conductors?
Or must the fuse be sized strictly within the conductor ampacity?
Thanks,
Alan
230.90(A) says "..protection shall be provided by an overcurrent device.. that has a rating no higher than the allowable ampacity of the conductor".
230.208 allows short circuit protection for the feeder supplied by the service disconnect, up to 3x the conductor ampacity. Would this rule also apply to service entrance conductors?
240.100 allows for protection to the thermal damage curve of the cable or, for feeders, up to 3x the conductor ampacity. Would this rule apply to service entrance conductors?
Or must the fuse be sized strictly within the conductor ampacity?
Thanks,
Alan