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© 2017 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 03/03/17
FUSE
Circuit Protection Products and Mounting Accessories
UL/CSA/ANCE (Mexico) 248-14 vs. IEC 60127 Part 2
FUSE OPENING TIMES vs. METI/MITI
Percent of
Rating
UL & CSA
STD 248-14
IEC TYPE F
Sheet 1 (*)
IEC TYPE F
Sheet 2 (*)
IEC TYPE T
Sheet 3 (*)
IEC TYPE T
Sheet 5 (*)
METI/MITI
110 4Hr.Min. — — — —
130 — — — — — 1Hr.Min.
135
60 Minutes
Max.
— — — —
150 —
60 Minutes
Min.
60 Minutes
Min.
60 Minutes
Min.
60 Minutes
Min.
160 — — — — — 1Hr.Max.
200
2 Minutes
Max.
— — — —
2 Minutes
Max.
210 —
30 Minutes
Max.
30 Minutes
Max.
2 Minutes
Max.
30 Minutes
Max.
(*) Note: The IEC Specification is written up to 10.0A. Any
components above these ratings are not recognized by
the IEC (although the fuses may have similar opening
characteristics).
IEC also has opening time requirements at 275%, 400%
and 1000%; however, the chart is used to show that
fuses with the same ampere rating made to different
specifications are not interchangeable. According to the
IEC 60127 Standard, a one ampere-rated fuse can be
operated at one ampere. A one ampere-rated fuse made
to UL/CSA/ANCE 248-14 should not be operated at more
than .75 ampere (25% derated — See RE-RATING section
of FUSEOLOGY).
METI
B
does not differentiate between fast-acting and time
delay characteristics.
Publication IEC 60127-4 (Universal Modular Fuse-Links
[UMF])
This part of IEC 60127-4 covers both PCB through-hole
and surface mount fuses. This standard covers fuses rated
32, 63, 125, and 250 volts. This standard will be accepted
by UL/CSA making it the first global fuse standard. This
specification uses different fusing gates than IEC 60127-2;
the gates used here are 125%, 200%, and 1000%.
The fuses must not open in less than one hour at 125%
of rated current and open within two minutes at 200% of
rated current. The 1000% overload is used to determine
the fuse characteristic. The opening time for each rating is
listed below.
Type FF : Less than 0.001 sec.
Type F : From 0.001 - 0.01 sec.
Type T : From 0.01 - 0.1 sec.
Type TT : From 0.1 - 1.00 sec.
These characteristics correlate to the terminology used in
IEC 60127-1.
Breaking capacity (interrupting rating) varies based on
voltage rating. Parts rated at 32 & 63 volts must pass a
test of 35 amperes or ten times rated current, whichever
is greater. Parts rated at 125 volts must pass a test of 50
amperes or ten times rated current, whichever is greater.
Parts rated at 250 volts are further defined as either low,
intermediate or high breaking. The low breaking capacity
fuses must pass a test of 100 amperes rated current, while
intermediate breaking capacity fuses must pass a test of
500 amperes and high breaking capacity fuses must pass a
test of 1500 amperes.
MILITARY/FEDERAL STANDARDS
MIL-PRF-15160 and MIL-PRF-23419
These specifications govern the construction and
performance of fuses suitable primarily for military
electronic applications.
MIL-PRF-19207
This specification governs the construction and
performance of fuseholders suitable for military
applications.
DSSC Drawing #87108
This drawing governs the construction and performance
of .177” × .570” (2AG size) cartridge fuses and axial lead
versions suitable for military applications. DSSC #87108
designation is included in the fuse end cap marking.
FEDERAL SPECIFICATION W-F-1814
This specification governs the construction and
performance of fuses with high interrupting ratings that are
approved for federal applications. Fuses approved to these
specifications are on the Federal Qualified Products List.
Write to the following agencies for additional information
on standards, approvals, or copies of the specifications.
Underwriters Laboratories Inc. (UL)
333 Pfingsten Road
Northbrook, Illinois, USA 60062-2096
Canadian Standards Association (CSA)
5060 Spectrum Way, Suite 100
Mississauga, Ontario, Canada L4W 5N6
International Electrotechnical Commission (IEC)
3, Rue de Varembe
1211 Geneva 20, Switzerland
Naval Publications and Military StandardsForm
Center (for Military and Federal Standards)
5801 Tabor Avenue
Philadelphia, Pennsylvania, USA 19120
Defense Supply Center Columbus (DSCC)
3990 East Broad Street
Columbus, Ohio, USA 43218-3990
Ministry of Economy Trade and Industry (METI)
1-3-1 Kasumigaseki
Chiyouda-ku, Tokyo 100-8901, Japan
Standards (continued)