UL 248-7:2000 pdf download – Low-Voltage Fuses – Part 7: Class H Renewable Fuses.
I General
NOTEThis Pan is nende4 to be read together ialth the Standard l Low- Voltage Fuses – Pan 1: General Requ&remenrs. hereafter
rele,red to as Pail I. The numberwrg oi die Clauses Ni this Part correspond to the numbered Clauses n Part 1. The requirements
01 Part I il unlss ,nodif led by this Part For Clauses not shoal below. rele, to the Standard for Low Voltage Fuss – Part 1
General AequArements, NMX-J-00924a7-2000-ANCE • CSA C22.2 No 248.1. IA 248-I.
1.1 Scope
This Part applies to Class H Renewable fuses rated 600 A or less and either 250 or 600 V ac. DC ratings are optional.
4 Classification
Class H Renewable fuses have an interrupting rating of 10.000 A. Each of the voltage ratings, 250 V ac and 600 V ac, is divided into six body sizes with the maximum current rating, l. for each size as specified in this Pan. These fuses are not ctassified as current limiting. Time-delay ratings are optional.
These fuses may be restored to service after operation by the replacement of the renewal element with one recommended by the manufacturer.
5 Characteristics
52 Voltage rating
For AC. the rating shall be 250 or 600 V ac in accordance with dimensions shown in Figures A and B.
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 cacti voltage rating.
8.4.3 Test method
Two successive tests shall be run with each fuse. For 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 miii. 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 pertomi in the intended manner, and be renewed within the allowable 10-minute element renewal period. Parts other man 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.
Dunng the renewal of the element, the fuse assembly shall not be damaged so that the element cannot be replaced in the intended manner. Breakage of a bridge or other part that usually maintains alignment of paris or integrity of the assembly constitutes inability to renew. Also. loosening of the threaded inserts to which the ferrules are attached, before reunsertion 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.