Table
Class J Fuse Ratings and Applications
Class J Fuse Ratings and Applications lookup table with assumptions and boundary notes.
Scope
Class J label planning only. It does not approve a replacement fuse, holder, circuit rating, selective coordination, or equipment application.
Lookup table
Read common Class J fuse label fields and catalogue descriptions.
Scroll sideways to keep row labels aligned with hidden columns.
| Label field | Field meaning | Typical value | Boundary |
|---|---|---|---|
| Rejection mounting | Use a rejection-style holder or fuse block lookup | Holder type | Class J label planning only; holder compatibility still requires product data |
| Voltage rating | Common Class J voltage label | 600 V | Class J label planning only; actual product marking governs field application |
| Ampere range | Common cartridge ampere range | 1 A to 600 A | Class J label planning only; actual product marking governs field application |
| Time-delay | Delay characteristic marking on some products | Time-delay | Class J label planning only; manufacturer curves govern response |
| Current limiting | Current-limiting fuse wording on some products | Current limiting | Class J label planning only; manufacturer curves govern let-through |
Notes
- Check table values for preliminary lookup and arithmetic checks only.
- Confirm equipment ratings, product markings, installation conditions, utility requirements, and the local authority requirements before design or field use.