Fuse Characteristics: CLASS_J
Fuse time-current characteristics, voltage ratings, interrupting capacity, and current-limiting classification by fuse class. Covers UL 248 classes (J, RK1, RK5, CC, T, L, G, H, K) and IEC 60269 types (gG, gM, aR, aM). Includes melting and clearing I2t let-through energy ranges, peak let-through current, conventional fusing/non-fusing current factors, rejection feature type, and application guidance.
| fuse class | record id | amp rating max (A) | amp rating min (A) | application | conventional fusing current factor (dimensionless) | conventional nonfusing current factor (dimensionless) | current limiting | dimensions ferrule blade | fuse type | interrupting rating kA ac (kA) | notes | peak let through kA at 100kA (kA) | rejection feature | time delay | ul standard | voltage rating V (V) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| CLASS_J | j_600v_fast | 600 | 1 | General purpose branch circuit; motor circuits; semiconductor protection; 1-600A 600VAC; dimensionally same as Class H but rejection feature prevents unsafe substitution; faster clearing than RK1/RK5 at same amp rating | 1.1 | 0.9 | current_limiting | ferrule_or_knife_blade | J | 200 | Class J provides superior current limitation (lower I2t and Ip) vs Class RK; rated 600VAC; common sizes: 1 6 10 15 20 25 30 35 40 45 50 60 70 80 90 100 110 125 150 175 200 225 250 300 350 400 450 500 600A | 1.35 | rejection_notch_rejection_blade | fast_acting | UL_248-8 | 600 |
| CLASS_J | j_600v_td | 600 | 1 | Time-delay Class J (e.g. Bussmann LPJ Littelfuse JTD); dual element; passes 500% for 10s minimum; motor branch protection at 600VAC; recommended for motor loads due to starting inrush tolerance | 1.1 | 0.9 | current_limiting | ferrule_or_knife_blade | J_time_delay | 200 | Dual-element: outer element (fuse link) responds to short circuits; inner element (spring-loaded solder joint) responds to sustained overloads; 10s minimum at 500% rated current per UL 248 | 1.35 | rejection_notch_rejection_blade | time_delay | UL_248-8 | 600 |
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