Reference boundary

Fuse-use terminology reference only. It does not decide whether a fuse may protect a circuit, device, motor, transformer, or panel.

Reference table

Compare branch-circuit and supplemental fuse markings as a label-reading reference.

Reference basis uses manufacturer fuseology descriptions of branch-circuit and supplemental fuse terminology.
Fuse use typeCommon equipment contextLabel cuesBoundary
Branch-circuit fuseBranch circuits, feeders, and equipment protection referencesLook for branch-circuit, general-purpose, or equipment-protection languageBranch-circuit label reference only; actual use depends on the product, holder, and equipment
Supplemental fuseControl circuits and supplemental protection referencesLook for supplemental or control-circuit languageSupplemental-fuse label reference only; actual use depends on the product, holder, and equipment
Semiconductor fuseDrive and power-electronics protection referencesLook for semiconductor, high-speed, or aR/gR product languageSemiconductor-fuse label reference only; manufacturer data governs actual device protection
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.