UL 248-7:2000 pdf download.Low-Voltage Fuses - Part 7: Class H Renewable Fuses.
8.4.3 Test method
Two successive tests shall be run with each fuse. Fo the first test, the fuse shall have an element installed. After this test has been run, the fuse shall be opened and the spent element replaced with a renewal element within an elapsed time of 10 mm. The test is repeated. The fuse need not be renewed after the second test.
8.4.4 Acceptability of test results
For Test 4c, AC and Test 1, DC, each fuse shall perform in the intended manner, and be renewed within the allowable 10-minute element renewal period. Parts other than the element are not to be replaced or omitted. Deposits of fused metal may be removed if such removal can be accomplished readily with a knife, screwdriver, or pliers.
During the renewal of the element, the fuse assembly shall not be damaged so that (he element cannot be replaced in the intended manner. Breakage of a bridge or other part that usually maintains alignment of parts or integrity of the assembly constitutes inability to renew, Also, loosening of the threaded inserts to which the ferrules are attached, before reinsertion of the new element into the body, also constitutes inability to renew. Inability to renew the fuse shall be considered as a non-conforming result.
Two successive tests shall be run with each fuse. Fo the first test, the fuse shall have an element installed. After this test has been run, the fuse shall be opened and the spent element replaced with a renewal element within an elapsed time of 10 mm. The test is repeated. The fuse need not be renewed after the second test.
8.4.4 Acceptability of test results
For Test 4c, AC and Test 1, DC, each fuse shall perform in the intended manner, and be renewed within the allowable 10-minute element renewal period. Parts other than the element are not to be replaced or omitted. Deposits of fused metal may be removed if such removal can be accomplished readily with a knife, screwdriver, or pliers.
During the renewal of the element, the fuse assembly shall not be damaged so that (he element cannot be replaced in the intended manner. Breakage of a bridge or other part that usually maintains alignment of parts or integrity of the assembly constitutes inability to renew, Also, loosening of the threaded inserts to which the ferrules are attached, before reinsertion of the new element into the body, also constitutes inability to renew. Inability to renew the fuse shall be considered as a non-conforming result.
