TF400 Replacement Fuse


8 in stock


400 Amp Class T Fuse. 300V

Space saving POWR-GARD Class T fuses are the most compact fuses available in ratings above 30 amperes — less than one-third the size of comparable Class R fuses. When rated in accordance with the NEC, Class T fuses provide fast-acting overload and short circuit protection for non-inductive circuits and equipment. Used in inductive circuits, the ampere rating of Class T fuses must be increased to prevent opening on inrush currents. In such instances, Class T fuses may provide only short circuit protection.

For motor and general purpose circuits where space is not critical, we recommend POWR-PRO™ JTD_ID Indicator series, LLNRK/LLSRK series, or FLSR_ID Indicator series.


  • Protection of individual electric services and meters.
  • Main switches containing Class T fuses may be used to provide compact protection for meter stacks.
  • Molded case circuit breaker load centers and panelboards have increased interrupting ratings when “series rated” with Littelfuse Class T fuses. Refer to panelboard manufacturers’ literature for UL Listed combination of fuses and panelboards.
  • Series ratings up to 200,000 amperes are available.

Space Saving:

  • Typical three-pole Class T fuse blocks require less than 50% of the panel area required for Class R fuse blocks. Switch enclosures, fuse pullouts, and other equipment using Class T fuses are often correspondingly more compact.


  • 200,000 A.I.R. — Reliable interruption of all overcurrents up to 200,000 amperes.
  • Extremely current limiting — Stops damaging short circuit current faster than any mechanical protective device.
  • Fast-Acting — Provides fast-acting overload protection to equipment such as variable speed drives, rectifiers and other equipment containing surge-sensitive components.

Longer Equipment Life:

  • Current limiting design greatly reduces damage to equipment caused by heating and magnetic effects of short circuit currents.


  • Extremely current limiting design often permits use of readily available, less costly equipment.
  • Used as input or output fuses for surge-sensitive components, such as variable speed drives and rectifiers, fast-acting Class T JLLN/JLLS fuses may prevent opening of expensive semiconductor fuses protecting individual components.

Additional information

Weight 1 lbs
Dimensions 4 × 4 × 7 in


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