In establishing fuse opening times for use in IEEE 1584 calculations over 300
tests were made using Class RK1 fuses from 30 through 600 amperes and Class L
fuses from 601 through 2000 amperes. Section 9.13 of IEEE 1584 states: “Fuses
from one manufacturer were used, but results with other manufacturers’ fuses of
the same class should be similar.”
In addition, IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. 36, NO. 6,
NOVEMBER/DECEMBER 2000 1741 The Use of Low-Voltage Current-Limiting Fuses to
Reduce Arc-Flash Energy states in part:
“II. CURRENT-LIMITING FUSE DATA-In order to determine the performance of
current-limiting fuses, fuse manufacturers typically perform single-phase
bolted-fault fuse tests based on the UL (U.S.)/CSA (Canada)/ANCE (Mexico)
tri-national 248 series of standards. Note that the 248 series of standards
calls out the maximum let-through values so that all fuses listed to the
standard will have a uniform maximum let-through which can be utilized by equipment
manufacturers and designers.”
Littelfuse fuses with short-circuit characteristics (opening times) consistent
with fuses used in the IEEE tests include: LLNRK, LLSRK, LLSRK_ID, KLNR, and
KLSR series (Class RK1); JTD, JTD_ID, and JLS series (Class J); KLPC and KLLU
series (Class L); JLLN and JLLS series (Class T); and CCMR, KLDR, and KLKR
series (Class CC).
Fuses not covered by the test date include: Class RK5, Class K5 ('One-Time'),
and Class H (Renewable) fuses. These types of fuses do not provide the degree
of arc-fault protection as the fuses listed above. It is recommended that Class
RK5, K5, and H be replaced with a suitable fuse having better short-circuit
characteristics.