UL 248-9-2010 pdf download

UL 248-9-2010 pdf download.Low-Voltage Fuses – Part 9: Class K Fuses.
1 General NOTE – This Part is intended to be read together with the Standard for Low-Voltage Fuses – Part 1 : General Requirements, hereafter referred to as Part 1 . The numbering of the Clauses in this Part correspond to like numbered Clauses in Part 1 . The requirements of Part 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-009/248/9-2000-ANCE ♦ CAN/CSA C22.2 No. 248.1 ♦ UL 248-1 . 1.1 Scope This Part applies to Class K fuses rated 600 A or less and either 250 or 600 V ac. DC ratings are optional. 4 Classification Class K fuses are non-renewable, with interrupting ratings of 50,000, 1 00,000, or 200,000 A. Class K fuses are divided into sub-classes K-1 , K-5, and K-9 which are physically interchangeable with each other (and Class H fuses) for the same current and voltage ratings. Each sub-class has specified limits of peak let-through current and clearing I 2 t characteristics. K-1 has the lowest limits (most current-limiting), K-5 higher, and K-9 highest. Each of the voltage ratings, 250 and 600 V ac, is divided into six body sizes. The maximum current rating, I n , for each size is specified in this Part. Time-delay ratings are optional. In Canada, 250V ac fuses rated 1 5 – 60 A shall have a low melting point ″P″ (″D″ for time delay) characteristic. See sub-clauses 6.1 and 9.2. 5 Characteristics 5.2 Voltage rating For AC, the rating shall be 250 or 600 V ac in accordance with dimensions shown in Figure A. The DC voltage rating may be different from the AC rating. 5.3 Current rating Refer to Figures A and B for range of current ratings in each body size for each voltage rating.
8 Tests 8.2 Verification of temperature rise and current-carrying capacity 8.2.3 Test method 1 .0 I n – Temperature rise 1 .1 I n – 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 1 5 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 – ≤1 00 A – 55°C >1 00 A – 75°C 8.3 Verification of overload operation Part 1 , Table 4 Test 1 – 1 .35 I n Test 3 – 2 I n Test 5 – 5 I n for time-delay fuses only. For 250 V ac rated 30 A or less, the clearing time shall be 8 s minimum.
8.4 Verification of operation at rated voltage For AC – Part 1 , Table 5 Test 1 – 50,000, 1 00,000, or 200,000 A in accordance with the interrupting rating of the fuse Test 2 – Maximum energy Test 4a – 1 00,000 A if less than the interrupting rating of the fuse Test 4b – 50,000 A if less than the interrupting rating of the fuse Test 5b – 2I n Peak let-through current and clearing I 2 t recorded during Test 1 . For DC – Part 1 , Table 6 Test 1 – Interrupting rating Test 2 – Maximum energy Test 5a – 9 I n for time-delay fuses only 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. 9 Special Tests 9.1 General 9.1 .1 Types of tests For fuses with a low melting point ″P″ (″D″: for time delay) characteristic, one fuse of each body size shall be tested.
9.2 Verification of low melting point ″P″ (″D″ for time delay) characteristic 9.2.1 The fuse shall open in an ambient of 200°C 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 of 200°C maximum with a test current of 1 0 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 the fuse and gradually increased from 0 V until rated voltage is reached or until the current exceeds 5 mA. The fuse shall be considered to have opened if the current between the fuse terminal parts does not exceed 5 mA when rated voltage is applied between such parts.UL 248-9-2010 pdf download.