UL-248-9:2015 pdf free download – STANDARD FOR SAFETY Low-Voltage Fuses – Part 9: Class K Fuses.
8 Tests
8.2 Verification of temperature rise and current-carrying capacity
8.2.3 Test melthod
1.01 – Temperature rise
1.1 hn – Curent-arying capacit, hnt
8.2.3.1 Fuses rated 600 A or less
In addition to the requirements in Part 1: At the conclusion of the temperature rise test, the test current shall be increased without iteruption to 1.1 h for a period of not less than 15 min for fuses rated 200
A and not less than 30 min ftor fuses rated 201 – 600 A. Temperalure is not to be monitored during this time.
8.2.4 Acepability of test results
In aditin to the requirements in Part 1: The maximum temperature rise shall not exceed the following Contacts – s100 A- 55%C
>100 A- 75°C
8.3 Verification of overload operation
Part 1, Table 4
Test1- 1.35 h
Test3-2In
Test 5- 5 In for time-delay fuses only. For 250 V ac rated 30 A or less, the clearing time shall
be 8 s minimum.
9.2 VerIfication of low melting point P (0 for time delay) characteristic
9.2.1 The fuse shaM open in an ambient of 200CC maximum when tested as specified in Clauses 9.2.2 and 9.2.3.
9.2.2 The fuse shall be placed in an ambient 01 200°C maximum with a test current 0110 percent of rating maximum for a period of 6 h maximum, After the fuse opens it shall be allowed to cool to room temperature 25 ± 5°C without being disturbed
9.2.3 A test voltage shall be applied to me fuse and gradually increased from 0 V until rated voltage is reached at until the current exceeds 5 mA. The fuse shalt be considered to have opened if the current between me fuse terminal parts does not exceed 5 mA when rated voltage is applied between such parts.