UL 4248-5:2018-04 Fuseholders – Part 5: Class G.
1.1.2 These requirements cover fuseholders intended for use with Class G Fuses as described in
NMX-J-009/248/5-2000-ANCE, CSA C22.2 No. 248.5, UL 248-5, Low-Voltage Fuses — Part 5: Class G Fuses.
4 Classification
4.1 Class G fuseholders have a short-circuit withstand rating of 100,000 A. Class G fuseholders are rated
480 V or 600 V, and have four body sizes corresponding to the Class G fuse body size.
5 Characteristics
5.1 Summary of characteristics
5.1.3 Voltage and current rating
5.1.3.1 Class G fuseholders shall be rated 480 or 600 V.
5.1.3.2 Class G fuseholders shall be rated 15, 20 A (600 V); 30, 60 A (480 V).
5.1.4 Withstand rating
5.1.4.1 Class G fuseholders shall have a short-circuit withstand rating of a 100,000 A.
6 Marking
6.1 Marking of fuseholders
6.1.1.1 In addition to the requirements of Part 1, the fuseholder shall be marked:
f) “Use Class G Fuses”;
g) For panel mount and in-line fuseholders, “line” and “load” shall be marked, with the terminal recessed furthest in the device designated as the line terminal; and
h) “DO NOT OPERATE UNDER LOAD” or equivalent for fuseholders of the modular design where the fuse is inserted or removed by use of a carrier.
8 Tests
8.1 General
8.1.1 Types of tests
8.1.1.1.1 Each fuseholder shall be subjected to the tests as specified in Part 1.
8.4 Verification of temperature rise
8.4.3 Test method
8.4.3.1 With dummy fuses in place and carrying rated current continuously, the temperature on a material or component or electrical insulation shall not exceed the values in Table 8.4B.
8.4.3.2 Dummy fuses shall be unplated copper and shall conform to the dimensions in Table 8.4A.
8.4.3.3 The temperatures specified in Table 8.4B are based on an assumed ambient temperature of 25°C
(77°F). A test may be conducted at an ambient temperature within the range of 20 — 40°C (68 — 104°F).
8.4.3.4 During a test conducted at an ambient temperature of 25°C (77°F), an observed temperature shall
not exceed the required value specified in Table 8.4B.
8.4.3.5 If a test is conducted at an ambient temperature other than 25°C (77°F), an observed temperature shall be corrected as described in Clause 8.4.3.4. Neither a corrected temperature nor an observed temperature shall exceed the required value specified in Table 8.4B.
8.4.3.6 An observed temperature is to be corrected by addition [if the ambient temperature is lower than
25°C (77°F)] or subtraction (if the ambient temperature is higher than 25°C) of the difference between
25°C and the ambient temperature.
8.4.3.7 If a corrected temperature exceeds the required value specified in Table 8.4B, at the request of the manufacturer, the test may be repeated at an ambient temperature closer to 25°C (77°F).UL 4248-5 pdf download.