Table

UL/CSA Fuse Class Reference

UL/CSA Fuse Class Reference reference with assumptions and boundary notes.

Reference boundary

Fuse class label reference only. It does not choose a fuse, verify holder compatibility, approve replacement, or determine interrupting rating.

Reference table

Compare common cartridge fuse class markings by form factor, voltage labels, and catalogue context.

Reference basis uses common fuse class descriptions from manufacturer fuseology and cartridge fuse literature.
Fuse classForm factor referenceCommon voltage labelsLabel cuesBoundary
Class JCartridge fuse300 V, 600 VRejection-style label cueClass label reference only; holder and equipment compatibility still require product data
Class CCCompact cartridge fuse300 V, 600 VCompact control-circuit label cueClass label reference only; holder and equipment compatibility still require product data
Class RK1Renewable / dual-element cartridge fuse250 V, 600 VTime-delay or dual-element label cueClass label reference only; holder and equipment compatibility still require product data
Class RK5Renewable / dual-element cartridge fuse250 V, 600 VTime-delay or dual-element label cueClass label reference only; holder and equipment compatibility still require product data
Class LLarge cartridge fuse600 VHigh-ampere cartridge label cueClass label reference only; holder and equipment compatibility still require product data
Use notes
  • Use this table for preliminary reference and arithmetic checks only.
  • Confirm equipment ratings, product markings, installation conditions, utility requirements, and the local authority requirements before design or field use.