I want to get the boxes we build up to 100kA SCCR as a standard...
So to do this we would put fuses ahead of any branch circuit in our box, plus use a 100kA SCCR rated distribution block, and use a 200kA SCCR rated fused disconnect. What has me stumped, or bothered, is the omission of class CC fuses below 15 amp in table SB 4.2. The omision of any class CC fuse below 15 amp in table SB 4.2 makes me think it is to be interpreted as me not being able to use class CC fuses below 15 amps even though the class CC fuses I use from Ferraz Shawmut are all 100kA SCCR regardless of fuse amp size...
As I read SB4.2, I am faced with the dilemma of either using class J fuses only (which are bigger and cost more) when I want to use a fuse below 15amps, or using class CC's at or above 15 amps only in order to maximize my SCCR ratings of branch circuits in my boxes because table SB4.2 does not list any class CC fuses less than 15 amp. I guess there is no real problems using the 15 amp class CC since I would likley be using 14 awg wire in any case, but it irks me not being able to use lower amp fuses becuase of what table SB 4.2 seems to be saying...
So my two questions are:
- Does anyone know why UL would omit any class CC fuses below 15 amp from table SB 4.2 in 508a?
- Do you agree that my interpretation of not being able to use any class CC fuses lower than 15 amp for branch circuit protection is correct in interpreting table SB 4.2?
Hopefully my ramble makes sense...
Thanks in advance for any input!
So to do this we would put fuses ahead of any branch circuit in our box, plus use a 100kA SCCR rated distribution block, and use a 200kA SCCR rated fused disconnect. What has me stumped, or bothered, is the omission of class CC fuses below 15 amp in table SB 4.2. The omision of any class CC fuse below 15 amp in table SB 4.2 makes me think it is to be interpreted as me not being able to use class CC fuses below 15 amps even though the class CC fuses I use from Ferraz Shawmut are all 100kA SCCR regardless of fuse amp size...
As I read SB4.2, I am faced with the dilemma of either using class J fuses only (which are bigger and cost more) when I want to use a fuse below 15amps, or using class CC's at or above 15 amps only in order to maximize my SCCR ratings of branch circuits in my boxes because table SB4.2 does not list any class CC fuses less than 15 amp. I guess there is no real problems using the 15 amp class CC since I would likley be using 14 awg wire in any case, but it irks me not being able to use lower amp fuses becuase of what table SB 4.2 seems to be saying...
So my two questions are:
- Does anyone know why UL would omit any class CC fuses below 15 amp from table SB 4.2 in 508a?
- Do you agree that my interpretation of not being able to use any class CC fuses lower than 15 amp for branch circuit protection is correct in interpreting table SB 4.2?
Hopefully my ramble makes sense...
Thanks in advance for any input!