24 Hour Emergency Fuse Service Available
We Ship Throughout the U.S.A
PRODUCT SEARCH                      

UL Class Fuses

Following are some of the basic characteristics of the UL fuse classes.  Please refer to UL Standards for fuse manufacturer ratings for more specific technical information:

Midget

  • All size 10x38mm
  • Ratings vary, Descriptions vary  (may include Time-Delay, Fast-Acting or Semiconductor versions)
  • UL Listed / Recognized for supplemental protection

Class CC

  • Rated 30A or less, 200kA I.R.
  • Current-Limiting, optional Time-Delay
  • All size 10x38mm, with rejection feature
  • UL Listed for Branch-Circuit protection

Class RK1

  • Rated 600A or less, 200kA I.R.
  • Current-Limiting
  • Sizes vary by ampere rating
  • Rejection feature
  • Time-Delay versions - for motors, safety switches, transformers, disconnects, control, arc flash mitigation
  • Fast-Acting versions - for loadcenters, panelboards, switchboards, bus duct, feeders, lighting
  • UL Listed for Branch-Circuit protection
  • Highest performance in class

Class RK5

  • Rated 600A or less, 200kA I.R.
  • Current-Limiting
  • Sizes vary by ampere rating
  • Rejection feature
  • Time-Delay
  • Typical applications - may include motor circuits, mains, feeders, branch circuits, transformers, service entrance
  • UL Listed for Branch-Circuit protection
  • Most economical, performance suitable in many application

UL Class K5

  • Rated 600A or less, 50kA I.R.
  • Not Current-Limiting
  • Sizes vary by ampere rating
  • Fast-Acting
  • No Rejection feature
  • Typical applications - may include feeders, branch circuits, resistive heating, residential and small commercial applications, HVAC
  • UL Listed for Branch-Circuit protection
  • Limited applications, low performance ratings

Class J

  • Rated 600A or less, 200kA I.R.
  • Current-Limiting
  • Sizes vary by ampere rating
  • Rejection by size
  • Typical applications - may include fused combo motor starters, MCCs, transformers
  • UL Listed for Branch-Circuit protection

Class G

  • Rated 600A or less, 100kA I.R.
  • Time-Lag
  • Sizes vary by ampere rating
  • Typical applications - may include branch-circuit protection
  • UL Listed for Branch-Circuit protection

Class T

  • Fuses rated 1200A or less, 200kA I.R.
  • Fuses rated 800A or less, 200kA I.R.
  • Extremely Current-Limiting
  • Sizes vary by ampere rating
  • Rejection by Size
  • UL Listed for Branch-Circuit protection

Class L

  • Rated 601-6000A, 200kA I.R.
  • Current Limiting
  • Sizes vary by ampere rating
  • Rejection by size
  • UL Listed for Branch-Circuit protection

Class H

  • Rated 600A or less, 10kA I.R.
  • Fast-Acting ("Renewable")
  • Not allowed for new applications; upgrade to RK1 or RK5

 

Give our fuse experts a call today @ 1-800-246-8336 or use our easy Fuse Store Quote Request 

 

Can't find the fuse you're looking for?  Or, have a discontinued or hard-to-find fuse?  Use our our Special Fuse Quote request form.