JLS Class J Fuses
600 VAC • Fast Acting • 1 – 600 Amperes
• JLS fuse characteristics are similar to KLNR/KLSR fast acting Class
RK1 fuses, but dimensionally are much smaller.
• 200,000 A.I.R. — Reliable interruption of all overcurrents up to
• Extremely current-limiting — Stops damaging short-circuit current
faster than any mechanical protective device.
• Fast acting — Provides fast acting protection to equipment such as
variable speed drives, rectifiers and other equipment containing surge
Longer Equipment Life
• Current-limiting design 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.
• Manufacturers of equipment containing dual voltage devices can
simplify manufacturing and reduce inventory by standardizing on 600
volt JLS fuses and Class J fuse blocks for all AC voltage ratings.
JLS series fuses provide space saving, fast acting overload and short-
circuit protection for non-inductive loads. When used for motors or other
inductive loads, the ampere rating of JLS series fuses must be increased
to prevent nuisance opening on in-rush currents. In such applications, JLS
fuses may provide only short-circuit protection. Consider using Littelfuse
POWR-PRO ® JTD or JTD_ID series time-delay fuses in such circuits.
Easy to use
• 200,000 A.I.R. rating minimizes need for short-circuit calculations.
NOTE: Littelfuse JLS fuses are not time-delay fuses. For applications
where short-duration surges and spikes may cause nuisance fuse
opening, consider the use of Littelfuse POWR-PRO JTD or JTD_ID
series time-delay fuses.
General purpose circuits with little or no motor load.
Resistive loads, such as resistance electric heat.
Loads requiring fast acting overload protection, such as equipment
containing solid-state devices.
600 Volts AC
200,000 aperes rs syetrical
1 – 600 aperes
Standard 248-8, Class J
UL Listed (File No: E81895)
CSA Certified (File No: LR29862)
QPL: Federal Specification No: WF-1814
Exaple part nuber (series & aperage): JLS 110
Recommended Fuse Blocks
LPSJ series, LJ600 series
Refer to the Blocks and Holders section of this catalog for additional inforation.