Bussmann JKS crosses to Marathon Special Products CJ-F. Both are Class J fast acting fuses rated 600 VAC. The table lists all 30 ratings from 1 A to 600 A, with the Mersen A4J and Littelfuse JLS numbers on the same line. Every line is an exact amp-for-amp match.
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Bussmann JKS to Marathon CJ-F cross reference
| Bussmann | Amps | Marathon | Mersen | Littelfuse |
|---|---|---|---|---|
| JKS-1 | 1 A | CJ-F1 | A4J1 | JLS001 |
| JKS-3 | 3 A | CJ-F3 | A4J3 | JLS003 |
| JKS-6 | 6 A | CJ-F6 | A4J6 | JLS006 |
| JKS-10 | 10 A | CJ-F10 | A4J10 | JLS010 |
| JKS-15 | 15 A | CJ-F15 | A4J15 | JLS015 |
| JKS-20 | 20 A | CJ-F20 | A4J20 | JLS020 |
| JKS-25 | 25 A | CJ-F25 | A4J25 | JLS025 |
| JKS-30 | 30 A | CJ-F30 | A4J30 | JLS030 |
| JKS-35 | 35 A | CJ-F35 | A4J35 | JLS035 |
| JKS-40 | 40 A | CJ-F40 | A4J40 | JLS040 |
| JKS-45 | 45 A | CJ-F45 | A4J45 | JLS045 |
| JKS-50 | 50 A | CJ-F50 | A4J50 | JLS050 |
| JKS-60 | 60 A | CJ-F60 | A4J60 | JLS060 |
| JKS-70 | 70 A | CJ-F70 | A4J70 | JLS070 |
| JKS-80 | 80 A | CJ-F80 | A4J80 | JLS080 |
| JKS-90 | 90 A | CJ-F90 | A4J90 | JLS090 |
| JKS-100 | 100 A | CJ-F100 | A4J100 | JLS100 |
| JKS-110 | 110 A | CJ-F110 | A4J110 | JLS110 |
| JKS-125 | 125 A | CJ-F125 | A4J125 | JLS125 |
| JKS-150 | 150 A | CJ-F150 | A4J150 | JLS150 |
| JKS-175 | 175 A | CJ-F175 | A4J175 | JLS175 |
| JKS-200 | 200 A | CJ-F200 | A4J200 | JLS200 |
| JKS-225 | 225 A | CJ-F225 | A4J225 | JLS225 |
| JKS-250 | 250 A | CJ-F250 | A4J250 | JLS250 |
| JKS-300 | 300 A | CJ-F300 | A4J300 | JLS300 |
| JKS-350 | 350 A | CJ-F350 | A4J350 | JLS350 |
| JKS-400 | 400 A | CJ-F400 | A4J400 | JLS400 |
| JKS-450 | 450 A | CJ-F450 | A4J450 | JLS450 |
| JKS-500 | 500 A | CJ-F500 | A4J500 | JLS500 |
| JKS-600 | 600 A | CJ-F600 | A4J600 | JLS600 |
All Marathon CJ-F fuses on this page are Class J, fast acting, 600 VAC. Matching rule: same fuse class, same voltage, same operating type and the exact amp rating. No nearest-rating substitutions.
Fast acting or time delay?
JKS, A4J, JLS and CJ-F are fast acting. They open fast on a fault and suit feeders with no big inrush, such as heaters and lighting. For motor and transformer circuits the print often calls for a time delay Class J fuse such as Bussmann LPJ-SP. The Marathon match there is CJ-T. Send the part number and we will confirm which one you need.
Fuse holders for Class J
Marathon Special Products builds the Class J holders too: open reinforced holders such as R6J30A3B and DIN rail enclosed holders such as 6SJ30A3IC. See also the MSP Class J fused disconnect switches.
Common questions
What is the Marathon equivalent of Bussmann JKS-30?
Marathon Special Products CJ-F30 is the Class J fast acting fuse at 30 A and 600 VAC. Mersen A4J30 and Littelfuse JLS030 are the same rating.
Is Marathon CJ-F fast acting or time delay?
CJ-F is the Class J fast acting series, 600 VAC, 1 A to 600 A. The CJ-T series is the Class J time delay fuse that crosses Bussmann LPJ-SP.
Which Marathon fuse crosses Mersen A4J or Littelfuse JLS?
The same CJ-F catalog number. Match the amp rating: A4J100 and JLS100 both cross to CJ-F100.
Will a Marathon CJ-F fit my Class J fuse holder?
Class J fuses are built to UL 248-8 dimensions for each amp range, so a CJ-F fits any Class J holder sized for the same amp range. Check the holder rating before you swap.
Get a cross-referenced quote
Send the Bussmann, Mersen or Littelfuse part number and the quantity. We send back the Marathon match, the lead time and a quote. Need help with fuses and holders for a panel? Book a time and we will go through the application.
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More cross references: all cross references · Bussmann LPJ to Marathon CJ-T · Marathon for data centers and BESS · Marathon Special Products collection
Bussmann and JKS are trademarks of Eaton. Mersen and A4J are trademarks of Mersen. Littelfuse and JLS are trademarks of Littelfuse, Inc. Applied Control Inc. is not affiliated with, endorsed by, or sponsored by these companies. Competitor part numbers appear here only to identify products for comparison. Confirm the final selection against the current manufacturer datasheets before purchase or installation.