Littelfuse LJ601003CR

The following guidelines help simplify the selection of an appropriate fuse holder:

1. Determine the system voltage: Since fuses are selected based on system voltage, the fuse holder should match the voltage rating of the fuse.
2. Determine the design short-circuit current: The available and/or design short-circuit current is an important consideration when determining the class of fuse and fuse holder to use. If the available short-circuit current cannot be determined, or if it varies with equipment location, select fuses with a 200,000 ampere interrupting rating (A.I.R.) and matching fuse holders with a withstand rating of 200,000 amperes to ensure maximum safety. Class H fuse holders accept Class H or Class K5 fuses (interrupting rating up to 50,000 amperes) and Class R fuses (interrupting rating of 200,000 A.I.R.). To prevent insertion of fuses with incorrect interrupting ratings, it is recommended to use Class R fuse holders with Class R fuses and Class H fuse holders with Class H or Class K5 fuses. These fuse holders are the same size, but Class R fuse holders feature a rejection function that only allows insertion of Class R fuses.
3. Determine the fuse type and ampere rating to use: In addition to the voltage and interrupting ratings mentioned above, the ampere rating, blowing characteristics (fast-acting or time-delay), and physical size of the fuse are other important considerations in fuse selection. Once the fuse type has been selected, a matching fuse holder can be chosen. Fuse holders are available in 30, 60, 100, 200, 400, and 600 ampere ratings and can be used with fuses of the corresponding ampere rating or lower. For example, a fuse holder rated at 30 amperes can be used with fuses rated from 0 to 30 amperes.
4. Determine whether NEC, CSA, UL, or other requirements apply: If the fuse holder is to be installed in equipment requiring agency certification, obtain the relevant requirements from the certifying agency before selecting fuses and fuse holders.
5. Select the wire termination type: Three wire termination types are available: a) Screw — for use with spade terminals or ring terminals. b) Screw with pressure plate — for use with solid or stranded wire without terminals. Recommended where vibration is a factor. c) Box connector — most durable. For use with all types of solid wire and Class B and Class C stranded wire. Not suitable for welding cable or other rope-stranded conductors. On midget and Class CC fuse holders, 1/4-inch quick-connect terminals rated up to 20A are available.
6. Determine the number of poles per fuse holder: The number of poles per fuse group is determined by the circuit characteristics. Options for combining individual fuse holders into a strip will depend on the available space and the type of wire used.
7. Determine whether reinforced fuse clips are required: Fuse clips may lose some tension over time. This can be prevented by specifying reinforced fuse clips. Reinforced clips are standard on certain fuse holders (see individual product pages).

• Phenolic blocks with side barriers for isolation.
• Fuse holders rated 100A and larger are equipped with spring-reinforced fuse clips. Reinforcement springs are optional for 30A and 60A fuse holders.
• Space-saving 30A design — up to 45% smaller than existing 30A fuse holders. Available with 30A interlocking add-on blocks to create any number of poles (contact factory for availability). Integrated DIN rail mounting allows the fuse holder to be securely snapped onto 35mm "hat" DIN rail without tools.