# Glass cartridge fuses 5 × 20 mm and 6.3 × 32 mm (1/4 × 1-1/4 in): size, panel holder panel thickness

> What are the sizes of 5×20 mm and 6.3×32 mm (1/4 × 1-1/4 inch, 3AG) glass fuses, and how thick a panel does a panel fuse holder take?

- Category: Electronics › Wiring & connectors
- Kind: Standard part
- Basis: Fuse designations (the size is the name) from Digi-Key, Schurter and Littelfuse pages; panel thickness figures only where labelled; cut-outs deliberately omitted
- Page: https://xemstudio.com/objects/glass-cartridge-fuses-5x20-and-6-3x32/ · JSON: https://xemstudio.com/api/geometry?object=glass-cartridge-fuses-5x20-and-6-3x32 · Plain text: https://xemstudio.com/objects/glass-cartridge-fuses-5x20-and-6-3x32/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files CC BY 4.0 or their publisher's license
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

**Exact dimensions.** Every file is drawn at true size with no tolerance added. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your process's clearance before making the part.

## Notes

- The two cartridge fuse sizes are named by their body diameter and length: 5 × 20 mm and 6.3 × 32 mm. The 6.3 × 32 mm size is the metric name for the inch 1/4 × 1-1/4 in fuse that Digi-Key's AGC listing says fits holders for '3AB, 3AG, 1/4 in x 1-1/4 in'. The 31.75 mm and 6.35 mm shown are exact conversions of 1-1/4 in and 1/4 in; the sources print the metric names 6.3 × 32 for the same fuse. End-cap length and body length are not published in the pages read.
- Panel holders: Schurter's FPG1 closed holder for 5 × 20 mm prints a maximum panel thickness of 6 mm. Littelfuse's 345 series enclosed holder (3AB, 3AG and 5 × 20 mm fuses) prints a panel thickness from .032 in to .310 in. Its text also carries '1/2-32 (2A) double-lead thread' next to the mounting-hole drawings, but the cut-out diameter and flat could not be read with a label.
- Panel cut-outs left out on purpose: Schurter's catalogue prints 11.7, 12, 12.7 and 13 mm figures next to FPG1 / FPG2 / FEF holders and the Littelfuse sheet prints .65 in and .558 in hex, but the copies read lose the labels (hole, flat, nut), so no cut-out is stated. Use the holder's own drawing; this site will add the cut-out when a labelled figure is read.
- No files: a cartridge fuse is a cylinder (plain), and the holders' outlines were not readable.
- McMaster-Carr links (glass tube fuses and panel-mount holders) are below.

## Mating features (exact size; open press / slide / run / socket by your process clearance, leave designed and clamp as drawn)

| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| 5 × 20 mm cartridge fuse | Ø5 × 20 | 5 × 20 fuse holder clips (holder maker's drawing governs) | designed | all |
| 6.3 × 32 mm (3AG) cartridge fuse | Ø6.35 × 31.75 (1/4 × 1-1/4 in) | 3AG / 3AB fuse holder (holder maker's drawing governs) | designed | all |

## Sizes

| fuse size | body Ø, mm (designation) | length, mm (designation) | inch form | panel holders read (maker figure) |
|---|---|---|---|---|
| 5 × 20 mm (IEC / European) | Ø5 | 20 | 5 × 20 mm | Schurter FPG1 (panel thickness max 6 mm); Littelfuse 345 (panel .032 to .310 in = 0.81 to 7.87 mm) |
| 6.3 × 32 mm (1/4 × 1-1/4 in, '3AG' / 'AGC' class) | Ø6.3 | 32 | 1/4 × 1-1/4 in = Ø6.35 × 31.75 mm (inch to mm conversion) | Littelfuse 345 (same holder family accepts 3AB, 3AG and 5 × 20 mm) |

## Where the files are

- Digi-Key: [AGC 20 A glass fuse: fits holders for 3AB, 3AG, 1/4 in x 1-1/4 in](https://www.digikey.com/en/products/detail/eaton-electronics-division/AGC-20-R/1876764) — web — Publisher's page; dimensions are facts
- Schurter: [FPG1 closed panel fuseholder for 5 x 20 mm: panel thickness max 6 mm](https://nl.schurter.com/datasheet/FPG1) — web — Publisher's page; dimensions are facts
- Littelfuse (chipsmall copy): [345 series panel mount enclosed fuse holders: 3AB, 3AG, 5 x 20 mm; panel .032 in min / .310 in max](https://datasheet.chipsmall.com/03450121H/391772.pdf) — web — Publisher's page; dimensions are facts
- Schurter: [Fuseholders catalogue (panel mounting hole figures printed without readable labels; not used)](https://www.acomee.com.mx/catalogos/catalogoss/SCHURTER FUSEHOLDERS.pdf) — web — Publisher's page; dimensions are facts
- McMaster-Carr: [Fast-acting glass tube fuses (free STEP/IGES per part, for your own design use; no redistribution)](https://www.mcmaster.com/products/fuses/fast-acting-glass-tube-fuses/) — STEP, IGES, PDF — McMaster-Carr site terms: personal design use, no redistribution (verify at link)
- McMaster-Carr: [Panel-mount fuse holders (free STEP/IGES per part, for your own design use; no redistribution)](https://www.mcmaster.com/panel-mount-fuse-holders) — STEP, IGES, PDF — McMaster-Carr site terms: personal design use, no redistribution (verify at link)

## Questions

**What size is a 3AG fuse in mm?**

1/4 × 1-1/4 in = Ø6.35 × 31.75 mm, usually written 6.3 × 32 mm.

**What size is a 5x20 fuse?**

Ø5 mm × 20 mm.

**How thick a panel does a 5x20 panel fuse holder take?**

Schurter FPG1: up to 6 mm. Littelfuse 345: .032 to .310 in (0.81 to 7.87 mm).

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