R3-11A Bayonet Lock 5x20mm Panel Mount Fuse Holder
Bayonet quarter-turn 5x20mm panel fuse holder, 10A 250VAC/125VDC, 50A interrupt. Black bakelite UL94 V0 body, 1/2″-28UNEF thread, phosphor copper terminals. Fast fuse replacement for production test and service panels. Compare with screw-cap R3-11B.
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R3-11A Bayonet Lock 5x20mm Panel Mount Fuse Holder
What Makes the R3-11A a Bayonet-Type Holder?
The R3-11A uses a bayonet-style cap. You push it in and give it a quarter turn to lock. You do not need to spin a threaded cap multiple times. This quarter-turn action cuts fuse replacement time dramatically, especially in production-line testing or service environments where technicians swap fuses repeatedly.
The body mounts through a 1/2″-28UNEF threaded hole and locks with a hex nut. The cap itself carries the “FUSE” marking and an arrow that shows the turn direction. Overall length is a compact 34.2mm, which leaves room for wiring behind the panel.
Electrical and Mechanical Specifications
- Model: R3-11A
- Fuse size: 5 x 20 mm cylindrical
- Rated current: 10A
- Rated voltage: 250VAC / 125VDC
- Interrupt rating: 50A
- Body material: Black bakelite (phenolic resin), UL 94 V0
- Cap type: Bayonet quarter-turn lock
- Mounting thread: 1/2″-28UNEF
- Front bezel diameter: 15.0mm
- Terminal material: 0.5mm phosphor copper
- Dielectric withstand: 3000VAC
- Contact resistance: <5mΩ
- Insulation resistance: >100MΩ
- Overall length: 34.2mm
- Body behind panel: 30.2mm
- Mounting thread engagement: 17.0mm
- Cap depth: 4.0mm
Bayonet vs Screw Cap: R3-11A vs R3-11B
| Feature | R3-11A (This Page) | R3-11B |
|---|---|---|
| Cap locking | Bayonet quarter-turn | Screw-on thread, full rotation |
| Fuse change speed | Fast (push + 90° turn) | Slower (multiple turns) |
| Best for | Frequent fuse swaps, production test | Infrequent maintenance, sealed panels |
| Vibration resistance | Good (bayonet detent) | Excellent (threaded cap) |
| Body material | Black bakelite UL 94 V0 | Black bakelite UL 94 V0 |
| Electrical ratings | 10A 250VAC/125VDC, 50A | 10A 250VAC/125VDC, 50A |
Choose the R3-11A when speed matters. Choose the R3-11B when the cap must stay locked through high vibration or after long-term sealing.
Why Black Bakelite?
The black phenolic body handles sustained heat without softening. It also resists tracking and surface arcing. Therefore, the R3-11A suits power supply inputs, charger circuits, and industrial control panels where the holder runs warm under load.
Phosphor copper terminals provide consistent spring pressure on the fuse ends. Contact resistance stays below 5mΩ. Meanwhile, the 3000VAC hi-pot test confirms reliable insulation between live parts and the mounting panel.
Typical Applications
- Production line test stations
- Bench power supplies
- Industrial control panels
- Battery charger inputs
- Audio and rack-mounted equipment
Datasheet
[Download R3-11A specification sheet (PDF)]R3-11A Panel fuse holder
For the screw-cap version, see: R3-11B.R3 (11B) Panel Mount Fuse Holder for 5×20mm Fuse
FAQ
1: What is a bayonet-type fuse holder?
A: A bayonet holder locks the cap with a quarter-turn push-and-twist motion. You push the cap in, rotate 90 degrees, and it clicks locked. No threading required.
2: What is the difference between R3-11A and R3-11B?
A: Both share the same bakelite body, 10A 250VAC/125VDC ratings, and 1/2″-28UNEF thread. R3-11A has a bayonet quarter-turn cap. R3-11B has a fully threaded screw cap.
3: What size fuse does it accept?
A: Standard 5x20mm cylindrical glass or ceramic fuses.
4: What are the electrical ratings?
A: 10A at 250VAC or 125VDC, with a 50A interrupt rating.
5: What panel hole is required?
A: A 1/2″-28UNEF threaded hole. The front bezel is 15.0mm in diameter.
6: Is the body flame retardant?
A: Yes, the black bakelite phenolic body is rated UL 94 V0.
7: How do I replace the fuse?
A: Push the cap in and turn 90 degrees counter-clockwise. The bayonet mechanism releases, and the cap comes off.
8: Which version should I choose for vibration-prone equipment?
A: Choose R3-11B (screw cap) for high vibration. R3-11A bayonet is better for frequent, fast fuse swaps.
