Standards FAQs
1. How can you find out what the UL rating would be for an IEC rated fuse (i.e. How can you convert the IEC rating to UL)?
2. Do you have fuses that can be used in "NEC Class 1 Division 2"?
How can you find out what the UL rating would be for an IEC rated fuse (i.e. How can you convert the IEC rating to UL)?
The standard way to do this is to multiply the IEC rating by 1.43 times. This is a good approximation to the UL rating. It gets the customer in the ballpark. The conversion factor is applied to either the UL or IEC fuse rating to arrive at the other rating. The formula is 1.43 X (IEC rating) = (UL rating)
Do you have fuses that can be used in "NEC Class 1 Division 2"?
In regards to fuse protection of motors, appliances and lamps in Class 1 Div 2 Locations (Groups A-D), Section 501.115(B)(3) of the 2005 National Electrical Code states that fuses can be used within general-purpose enclosures if they are a nonindicating, filled, current limiting type. This letter is to inform you that the following fuses are a nonindicating, filled and current limiting type, which meets the requirements of NEC section 501.115(B)(3).
Class CC
CCMR 2/10 through 30A
KLKR 1-½ through 30A
KLDR 1/10 through 30A
Class RK1
LLNRK 1/10 through 600A
LLSRK 35 through 600A
KLNR 1 through 600A
KLSR 1 through 600A
Class RK5
FLNR 1/10 through 600A
FLSR 1/10 through 600A
Class L
KLPC 601 through 6000A
KLLU 601 through 4000A
Class T
JLLN 1 through 1200A
JLLS 1 through 800A
Class J
JLS 1 through 600A
JTD 1 through 600A
Class G
SLC ½ through 60A
The attached document provides additional information for your reference.
NEC Class 1 Div 2 Fuses
Littelfuse-Fuses-NEC-Class-1-Division-2-c.pdf
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