Blocks and Holders Fuse Blocks General Information 4. Determine if NEC, CSA, UL, or other requirements are applicable If fuse blocks will be installed in equipment to be submitted for agency approval, the requirements should be obtained from the approving agency in advance of fuse and fuse block selection. 5. Select the type of wire termination A choice of three types of wire termination is available: a) Screw* -- for use with spade lugs or ring terminals. b)Screw with Pressure Plate* -- for use with solid or stranded wire without terminal. Recommended where vibration will be a factor. c) Box Lug -- the most durable. For use with all types of solid wire and Class B and Class C stranded wire. Not for use with welding cable or other rope-stranded conductors. * 1/4" Quick Connect terminals rated for up to 20A are available on the Midget and Class CC fuse blocks. Fuse Block Selection The following guidelines should help simplify the selection of proper fuse blocks: Screw with Pressure Plate (P) 1. Determine the system voltage Since fuses are selected on the basis of system voltage, fuse blocks are selected to match the voltage rating of the fuse. Screw (S) Box Lug (C) 6. Decide on the number of poles in each block 2. Determine the design short-circuit current Class H fuse blocks will accept Class H or K5 fuses (which have an interrupting rating of up to 50,000 amperes) and Class R fuses (which have a 200,000 A.I.R.). To prevent the possibility of inserting a fuse with the incorrect interrupting rating, the use of Class R fuse blocks is recommended for use with Class R fuses. Use Class H fuse blocks with Class H or K5 fuses. These fuse blocks are dimensionally the same, but the Class R fuse blocks incorporate a rejection feature which allows only Class R fuses to be inserted. The number of poles for each set of fuses is determined by the characteristics of the circuit. The option to gang individual fuse blocks into long strips will be determined by the available space and by the type of wire being used. Blocks and Holders Available and/or design short-circuit current is an important consideration when determining the class of fuse and fuse blocks to use. If available short-circuit current cannot be determined, or if it will vary with equipment location, select fuses with a 200,000 ampere interrupting rating (A.I.R.) and mating fuse blocks with a withstand rating of 200,000 amperes for maximum safety. 7. Determine if fuse clips need to be reinforced Fuse clips may have a tendency to lose some of their tension over a period of time. This may be prevented by specifying reinforced fuse clips. Reinforced clips are standard on certain fuse blocks (see individual product pages). Ordering Information The Littelfuse fuse block part number consists of 6 or 7 components, as shown below and in the individual fuse block data tables. 3. Determine the type and ampere rating of the fuse to be used In addition to voltage and interrupting rating as discussed above, the fuse ampere rating, opening characteristics (fast acting or time-delay) and size are other important considerations in fuse selection. Once the fuse type is selected, the mating fuse block can be chosen. Fuse blocks are available in 30, 60, 100, 200, 400 and 600 amp ratings, and may be used with a fuse rated at the corresponding amperage rating or below. For example, a fuse block rated at 30 amperes may be used with a fuse rated from 0 to 30 amperes. For all Class R, H, J, T and 15, 20 & 60A Class G Fuse Blocks (c) 2005 Littelfuse * POWR-GARDTM Products Catalog www.littelfuse.com For all Class CC, Midget and 30A Class G Fuse Blocks 111 Blocks and Holders Class T Fuse Blocks 300 and 600 Volt Features/Benefits Bases are molded phenolic. To provide a low resistance connection and long-range reliability, steel reinforcing springs are supplied as standard. Larger blocks employ an integral heat sink for maximum heat dissipation. Specifications Voltage Ratings: Ampere Ratings: Approvals: 300 Volts AC 600 Volts AC 0 - 600 amperes UL Listed (File No. E14721) CSA Certified (File No. LR73091) Recommended Fuses JLLN (300V) and JLLS (600V) series fuses 300 and 600 volt fuse blocks are designed for use with miniaturized Class T fuses. Class T fuses are very fast acting, current-limiting, and approximately one-third the size of electrically comparable Class RK1 fuses. Class T 300V Amp Rating 30 60 Blocks and Holders 100 200 400 600 Class T 600V No. of Poles Catalog Number 2 3 2 3 4 1 2 3 1 1 1 LT30030-2 LT30030-3 LT30060-2 LT30060-3 LT30060-4 LT30100-1 LT30100-2 LT30100-3 LT30200-1 LT30400-1 LT30600-1 Connector Type (Add Suffix Shown) Screw Box Lug CR CR CR CR CR C C C C C C Maximum Wire Size Amp Rating S = #10 CU C = #2 CU 30 1 2 3 1 2 3 1 2 3 1 1 1 LT60030-1 LT60030-2 LT60030-3 LT60060-1 LT60060-2 LT60060-3 LT60100-1 LT60100-2 LT60100-3 LT60200-1 LT60400-1 LT60600-1 60 #2 0 CU-AL 100 250 MCM CU-AL (2) 250 MCM CU-AL (2) 500 MCM CU-AL 1.19 [30.2] 200 400 600 Connector Type (Add Suffix Shown) Screw Box Lug SR SR SR CR CR CR CR CR CR C C C C C C Maximum Wire Size S = #10 CU C = #2 CU-AL C = #2 CU-AL #2 0 CU-AL 250 MCM CU-AL (2) 250 MCM CU-AL (2) 500 MCM CU-AL Note: Reinforcing springs standard on all 600 volt Class T fuse blocks up to 60 amperes. 600 volt Class T blocks 100 amperes and larger have stud mountings. 1.19" 1.13" [30.2] [28.6] 0.218" [5.54] THRU 0.39" [9.91] C'BORE x 0.44" [9.91] DP. 2.88" 2.88 [73.0] [73.0] 2.25" 2.25 [57.2] .31 [7.9] [57.2] 1.13 [28.6] 2.38 [60.3] 2 POLE 120 Catalog Number C = #2 CU-AL Note: Reinforcing springs standard on all 300 volt Class T fuse blocks up to 100 amperes. 300 volt Class T blocks 200 amperes and larger have stud mountings. LT30030 No. of Poles .31" [7.9] 1.13" 0.62" [15.9] [28.6] 3.50" 1.12" [88.9] [28.5] 3 POLE www.littelfuse.com (c) 2005 Littelfuse * POWR-GARDTM Products Catalog Blocks and Holders Class T Fuse Blocks 300 Volt 4.47" LT30060 1.19" 1.19 [30.2] 1.13" [30.2] [113.5] 0.218" [5.54] THRU 0.39" [9.91] C'BORE x 0.44" [9.91] DP. [28.6] 3.09" [78.6] 2.88" 2.88 [73.0] [73.0] 2.25" 2.25 [57.2] 0.31 [7.9] [57.2] 1.13 [28.6] .31" 1.13" [28.6] [7.9] 2.38 [60.3] 3.50" [11.1] 0.20" [88.9] [5.2] 1.20" [30.6] 2 POLE LT30100 1.37 [34.8] 3 POLE .203" [5.1] DIA.HOLE .37" [9.5] C'BORE 3.09" [15.9] [32.5] 2.06" 52.4] 4.12" [78.6] 1.41" 0.18" [104.6] [35.7] 5.25" [4.6] 5.25" 4.78" [133.3] [121.4] 4.50" 4.50" [114.3] [39.6] 1.28" 4 POLE [133.3] 1.56" 0.62" 0.44" [114.3] 2.39" [60.7] 1 POLE [17.5] LT30200 [69.8] 0.69" [17.5] LT30400 LT30600 2.37" 1.50" [38.1] .281" [7.1] DIA.HOLE .50" [12.7] C'BORE 1.87" [47.5] 3 POLE 2 POLE Blocks and Holders 2.75" 0.69" [60.2] 2.25" 0.62" [57.1] [15.7] .18" 2.75" 0.37" 2.62" [69.8] [66.5] 0.62" [9.5] [15.7] [4.6] 7.00" 8.75" [177.8] [222.2] 6.25" 1.69" [158.7] 1.84" 7.37" [46.7] [187.3] [42.9] 8.12" [206.2] .69" [17.5] 2.25" [57.1] 1.12" [28.6] 1 POLE (c) 2005 Littelfuse * POWR-GARDTM Products Catalog 2.03" 8.06" [51.6] [203.2] 0.28" [7.1] DIA HOLE 0.19" 0.50" [12.7] C'BORE [48] x 0.43" [10.9] DEEP 1 POLE www.littelfuse.com 0.28" [7.1] DIA HOLE 0.19" 0.50" [12.7] C'BORE [4.8] x 0.43" [10.9] DEEP 1 POLE 121 Blocks and Holders Class T Fuse Blocks 600 Volt LT60030 0.218" x 0.655" 0.218" x 0.655" 3.13" 1.44" 0.91" [5.54 x 16.64] SLOT 2 PLS. [36.5] [79.4] 0.78" [23.0] [20] 0.33" [8.3] [20] [39.7] 1.56" [119] [39.7] 3.38" 3.38" [85.7] [85.7] 3.19" 4.69" 0.78" 1.56" [5.54 x 16.64] SLOT 2 PLS. [81.0] 1.69" 1.69" [42.9] [42.9] 0.62" 0.55" [13.9] 1.28" 0.33" [8.3] 1 POLE [32.5] 3 POLE 2 POLE LT60060 0.218" x 0.655" 0.218" x 0.655" 1.81" 0.91" [5.54 x 16.64] SLOT 2 PLS. 3.13" [46.0] 0.78" [23.0] [20] [79.4] [20] [39.7] 1.56" [119] [39.7] 3.38" 3.38" [85.7] [85.7] 2.31" [5.54 x 16.64] SLOT 2 PLS. 4.69" 0.78" 1.56" [15.9] [58.7] 1.69" 1.69" [42.9] Blocks and Holders [42.9] 0.63" 1 POLE LT60100 1.37 [34.8] 3 POLE 2 POLE 0.203" [5.1] DIA.HOLE 0.37" [9.5] C'BORE 6.06' 6.06" 4.78" [153.9] [121.4] 5.31" 2.36" 5.31" [134.9] [6.0] 0.18" [4.6] [104.6] [78.6] [16] [44.2] 4.12" 3.09'" [153.9] 1.74" [134.9] 2.39" [60.7] 0.69" [17.5] 1 POLE 122 1.41" 2.75" 2 POLE 3 POLE [35.7] [69.8] www.littelfuse.com 0.69" [17.5] 1.87" [47.5] (c) 2005 Littelfuse * POWR-GARDTM Products Catalog Blocks and Holders Class T Fuse Blocks 600 Volt LT60200 1.50" 0.281" [7.1] DIA.HOLE [38.1] 0.50" [12.7] C'BORE 2.37" [60.2] 2.25" [57.1] LT60400 .18" [4.6] 0.62" [15.7] 7.75" [196.8] 8.25" 7.0" 2.50" [209.5] [177.8] 2.72" [63.5] 9.00" [69.1] [228.6] 0.75" [19.0] LT60600 0.37" [9.5] 2.25" 1.12" [57.1] 1 POLE [28.6] 2.62" 2.75" [66.5] [69.8] 0.62" [15.7] 0.28" [7.1] DIA HOLE 0.50" [12.7] C'BORE x 0.43" [10.9] DEEP 1 POLE 0.19" [4.8] 6T400 6T200 9.0" [228.6] 2.95" [75.0] 9.75" [247.6] 1 POLE Blocks and Holders 0.28" [7.1] DIA HOLE 0.50" [12.7] C'BORE x 0.43" [10.9] DEEP 0.19" [4.8] 6T600 (c) 2005 Littelfuse * POWR-GARDTM Products Catalog www.littelfuse.com 123