JLLS050 - JLLS Series

Series: JLLS
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Space-saving 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 JLLS fuses may prevent opening of expensive semiconductor fuses protecting individual components.
Property (Mouseover for details) Value
Ampere Rating (A) 50
VAC (V) 600
VDC (V) 300
Interrupting Rating 20 kA @ 300 Vdc
Opening Fast-Acting (F)
Size Industrial Cartridge
Part # Part Description RoHS Pb-free RoHS (2015/ 863/EU) Certificate REACH (SVHC’s) Declaration Halogen Free REACH (SVHC’s)
JLLS050.T FUS 600V F/A CLASS T 50A RoHS No 05/09/2006 PbFree No 05/09/2006 CoC_RoHS10_JLLS050.T_02-05-2020 REACH205_Declaration_JLLS050.T_02-05-2020 No
Does not Contain
JLLS050.TXP FUS 600V F/A CLASS T 50A PLTD RoHS No 05/09/2006 PbFree No 05/09/2006 No
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