UL 248-13:2000 pdf download Low-Voltage Fuses – Part 1 3: Semiconductor Fuses
NOTE –
This Part is intended to be read together with the Standard for Low-Voltage Fuses – Part 1: General Requirements, hereafterreferred to as Part 1. The numbering of the Clauses in this Part corespond to like numbered Clauses in Part 1. The requirementsof Pat 1 apply unless modified by this Part. For Clauses not shown below, refer to the Standard for Low-Voltage Fuses – Part 1General Requirements,NMX-J-009/248/13-2000-ANCE + CSA C22.2 No.248.1 UL 2481.
1.1 Scope
This Part applies to semiconductor fuses rated 2000 V ac or less. DC ratings are optional.
Note: The Canadian Electrical Code, Part l, defines low votage as any voltage from 31 to 750 V inclusive and high voltage as anyvoltage above 750 V. The National Electrical Code, NFPA 70-1996 , Section 710-2 defines high voltage as more than 600 Vnomina/.
2 Definitions
2.2 General Terms
2.2.15 Semiconductor fuse
A fuse, letter designation “R,” intended only for protection or isolation of semiconductor devices such asSCR’s diodes.and the like, and not branch-circuit protection.
2.2.15.1 “g”Fuse
A fuse capable of interrupting under specified conditions all currents which cause melting of thefuse-element up to its interrupting rating.
2.2.15.2″a”Fuse
A fuse capable of interruptina, under specified conditions, all currents between the lowest current specifiedby the manufacturer and its interrupting rating.
4 Classification
Semiconductor fuses are non-renewable. They shall provide short-circuit protection and may provideoverload protection.
gR – Full-range, overload and short-circuit protection.
aR – Partial-range, short-circuit protection.
5 Characteristics
5.2 Voltage rating
For AC, the rating shall be 2000 V ac or less.
The DC voltage rating may be different from the AC rating.
5.5 Interrupting rating
For AC, the preferred ratings are 25,000, 50,000,100,000, or 200,000 A.For DC, the preferred ratings are 20,000, 50,000, 100,000, 150,000, or 200,000 A.5.6 Peak let-through current and clearing 2t characteristics
Maximum values of peak let-through current and clearing 1 are provided by the manufacturer. SeeClause 8.5.3.
6Marking
6.1 Marking of fuses
in addition to the marking requirements in Part 1: A semiconductor fuse shall be marked with:e) the fuse class or classification (See Clause 6.2):gR(Full-range); or
aR(Partial-range); and
g) the marking “Current Limiting” may be applied if the fuse complies with the threshold ratiotest.
UL 248-13:2000 pdf download
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