Low-voltage fuse cross-reference by UL class and manufacturer
Which fuse catalog series from each major manufacturer (Edison, Brush/Dorman, Bussmann, Mersen/Gould, GEC/CEFCO, Littelfuse) is the interchangeable equivalent for a given UL fuse class (CC, RK1, RK5, J, T, L, Midget, ceramic/glass supplementals). One record is one fuse type/class/voltage combination, with each manufacturer's series designation printed against it, plus the amp rating that must be added to complete the catalog number. Answers 'what is the Bussmann equivalent of a Littelfuse KLKR fuse', 'I have an old panel fused with Gould A2D fuses, what do I replace them with', 'what class is an FRN-R fuse'. There is no federal or UL-published cross-reference; each manufacturer prints only its own outbound mapping (its series vs everyone else's), never a neutral grid, and distributor sites that do publish one (Bussmann's own cross-reference tool, Mersen's own page) still favour their own house brand and are JS-driven lookup tools rather than a static table a reader or an assistant can scan in one place.
The data
| UL fuse class / type | Operating style | Voltage rating | Edison series | Brush/Dorman series | Bussmann series | Mersen/Gould series | Littelfuse series | GEC/CEFCO series | Mersen/Gould note |
|---|---|---|---|---|---|---|---|---|---|
| 1/4”x1/4” Ceramic | Fast-Acting | 250/125 | ABC | ABC | ABC | GAB | 314 | ||
| 1/4”x1/4”Glass | Fast-Acting | 250/32 | AGC | AGC | AGC | GGC | 312 | ||
| RK5 | Time-Delay Dual Element | 250 | ECNR | FRN-R | TR | FLNR | |||
| RK5 | Time-Delay Dual Element | 600 | ECSR | FRS-R | TRS | FLSR | |||
| CC | Time-Delay | 600 | EDCC | LP-CC | ATDR | CCMR | |||
| 5x20 mm Glass | Fast-Acting | 250/125 | GMA | GMA | GMA | GGM | 235 | ||
| 5x20 mm Glass | Medium Time-Delay | 250/125 | GMC | GMC | GMC | GSC | |||
| CC | Fast-Acting | 600 | HCLR | HCLR | KTK-R | ATMR | KLKR | CTK-R | |
| CC | Time-Delay | 600 | HCTR | FNQ-R | ATQR | KLDR | |||
| J | Time-Delay Dual Element | 600 | JDL | LPJ | AJT | JTD | |||
| J | High-Speed AC Drive | 600 | JHL | DFJ | HSJ | ||||
| L | Fast-Acting | 600 | LCU | LCU | KTU | A4BY | LDC | CL, CLU | |
| RK1 | Time-Delay Dual Element | 250 | LENRK | LPN-RK-SP | A2DR | LLNRK | |||
| RK1 | Time-Delay Dual Element | 600 | LESRK | LPS-RK-SP | A6DR | LLSRK | Not dual element 110–600Amp | ||
| Midget | Fast-Acting | 600 | MCL | MCL | KTK | ATM | KLK | CTK | |
| 1/4”x1/4” Ceramic | Time-Delay | 250 | MDA | MDA | MDA | 326 | |||
| 1/4”x1/4”Glass | Time-Delay | 250/32 | MDL | MDL | MDL | GDL | 313 | ||
| Midget | Time-Delay | 250 | MEN | MEN | FNM | TRM | FLM | ||
| Midget | Time-Delay | 500 | MEQ | MEQ | FNQ | ATQ | FLQ | ||
| Midget | Fast-Acting | 250 | MOL | MOL | BAF/BAN | OTM | BLF | ||
| 5x20 mm Glass | Fast-Acting | 250 | S500 | BDB | GDB | GSB | 217 | ||
| 5x20 mm Glass | Time-Delay | 250 | S506 | BDC | GDC | GDG | 218 | ||
| T | Extremely Fast-Acting | 300 | TJN | JJN | A3T | JLLN | |||
| T | Extremely Fast-Acting | 600 | TJS | JJS | A6T | JLLS |
Where this came from
Every record above links the page it was taken from and quotes the sentence that states it. These are the 2 sources this dataset was assembled from.
- cdn.automationdirect.comhttps://cdn.automationdirect.com/static/specs/efusexref.pdf
- cdn.automationdirect.comhttps://cdn.automationdirect.com/static/specs/efuserk1.pdf
Machine-readable
- data.jsonThe whole dataset — every record with its source URL and source quote.
- Open Knowledge Format bundleOne JSON object per line — every record's frontmatter and quoted span exactly as it is held here, in one fetch.
- data.csvThe same records as one flat table, for a spreadsheet or a dataframe. The last four columns are the source URL, the quoted sentence it was read from, the date we last checked it, and which columns are our reading rather than the page's words.
- How this is made and checkedWhat "verified against source" does and does not mean.
From your own code
Same records, same quotes, without scraping the page: refsource is on PyPI and npm. Each value comes back carrying the URL it was read from and the sentence on that page that states it — .source and .quote sit on the value itself rather than in a side channel, so the checking step is available instead of skipped.
pip install refsource
refsource lookup fuse-cross-reference-by-manufacturer-class operating_style=Fast-Acting
npx -y refsource lookup fuse-cross-reference-by-manufacturer-class operating_style=Fast-ActingSet your AI assistant up to use this
Two files and no account. Put this in .mcp.json at the root of your project — Claude Code, Cursor, Windsurf, VS Code and Codex all read that file — and your assistant can look this dataset up instead of recalling it. The server is remote, keyless and read-only.
{
"mcpServers": {
"referencesource": {
"type": "http",
"url": "https://referencesource.org/mcp"
}
}
}Add to Cursor · or, on the command line: claude mcp add --transport http referencesource https://referencesource.org/mcp --scope project
Then one line in the project's CLAUDE.md or AGENTS.md, so the assistant knows when to reach for it:
When a question needs "Low-voltage fuse cross-reference by UL class and manufacturer", call the referencesource MCP server at https://referencesource.org/mcp (tool `search_records`, dataset_slug `fuse-cross-reference-by-manufacturer-class`) instead of answering from memory — every record it returns carries its source URL and a verbatim quote from that page.What each tool does, and the servers built over single registers: Connect your AI assistant.