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