UL 248-2-2019 pdf download.Low-Voltage Fuses – Part 2: Class C Fuses.
1 General NOTE – This Part is intended to be read togetherwith the Standard forLow-Voltage Fuses – Part 1: General Requirements, hereafterreferred to as Part 1. The numbering ofthe Clauses in this Part corresponds to like numbered Clauses in Part 1. The requirements ofPart 1 apply unless modified by this Part. For Clauses not shown below, refer to the Standard for Low-Voltage Fuses – Part 1: General Requirements, NMX-J-009/248/2-2000-ANCE ♦ CAN/CSA C22.2 No. 248.1 ♦ UL 248-1. 1.1 Scope This Part applies to Class C fuses rated 1200 A or less and 600 Vac. DC ratings are optional. 4 Classification Class C fuses are non-renewable with an interrupting rating of 200,000 A. Class C fuses are divided into eight body sizes. The maximum current rating, I n , for each size is specified in this Part. 5 Characteristics 5.2 Voltage rating For AC, the rating shall be 600 Vac. The DC voltage rating may be different from the AC rating. 5.3 Current rating Refer to Figure A for range of current ratings in each body size. 5.5 Interrupting rating For AC – 200,000 A. For DC, the preferred ratings are 10,000, 20,000, 50,000, 100,000, 150,000, or 200,000 A. 5.6 Peak let-through current and clearing I 2 t characteristics Maximum values of peak let-through current and clearing I 2 t are given in Table A.
8.2 Verification of temperature rise and current-carrying capacity 8.2.3 Test method Fuses rated 0 – 600 A 1.0 I n – Temperature rise 1.1 I n – Current-carrying capacity, I nf Fuses rated 601 – 1200 A 1.1 I n – Temperature rise and current-carrying capacity, I nf 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 interruption to 1.1 I n for a period of not less than 15 min for fuses rated 0 – 200 A and not less than 30 min for fuses rated 201 – 600 A. Temperature is not to be monitored during this time. 8.2.4 Acceptability of test results In addition to the requirements in Part 1: The maximum temperature rise shall not exceed the following: Contacts – 0 to 100 A – 55°C 101 to 600 A – 75°C 601 to 1200 A – 75°C above calibration temperature 8.3 Verification of overload operation 8.3.4 Acceptability of test results The maximum clearing time (t max ) at 1.6 I n shall not exceed the following:60 min (Fuses rated 0 – 60 A) 120 min (Fuses rated 61 – 200 A) 240 min (Fuses rated 201 – 1200 A) 8.4 Verification of operation at rated voltage For AC – Part 1, Table 5 Test 1 – 200 kA Test 2 – Maximum energy Test 5b – 2 I n For DC – Part 1, Table 6 Test 1 – Interrupting rating Test 2 – Maximum energy Test 5c – 2 I n 8.5 Verification of peak let-through current and clearing I 2 t characteristics 8.5.3 Acceptability of test results Peak let-through current and clearing I 2 t values recorded shall not exceed the limits specified in Table A.UL 248-2-2019 pdf download.
UL 248-2-2019 pdf download
