R3-54B Screw-Lock 5x20mm Panel Mount Fuse Holder
Bolt-nut locked 5x20mm panel fuse socket: 10A 125VDC / 6.3A 250VAC, 50A break. PBT UL94 V0 body, 16mm bezel, phosphor copper terminals. Vibration-resistant fixing for industrial and portable equipment. Compare with snap-in R3-54A.
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R3-54B Screw-Lock 5x20mm Panel Mount Fuse Holder
Screw-Lock vs Snap-In: Which Do You Need?
The R3-54B and the R3-54A share the same electrical ratings and overall envelope. They differ only in how they fasten to the panel. The R3-54A snaps into the cutout with a spring latch. The R3-54B, by contrast, uses a threaded body with a hex nut.
Choose the R3-54B when your equipment sees vibration, shipping shock, or repeated service cycles. A threaded nut does not back off under lateral load the way a spring latch can. Therefore, engineers typically specify the bolted version for industrial machinery, portable tools, and vehicle-mounted electronics.
Electrical Ratings at a Glance
- Fuse cartridge: 5 x 20 mm
- DC rating: 10A at 125VDC
- AC rating: 6.3A at 250VAC
- Breaking capacity: 50A
- Housing: PBT, UL 94 V0
- Terminals: 0.5mm phosphor copper
- Dielectric withstand: 3000VAC
- Insulation resistance: >100MΩ
- Contact resistance: <5mΩ
Mechanical Data
The front bezel measures 16.0mm across, which covers a Ø12.7mm panel hole. Behind the panel, the body extends 30.5mm; total length to the terminal end reaches 38.6mm. The terminal tab is 12.0mm wide by 12.7mm tall, with a 2.8mm mounting hole.
Because the R3-54B uses a nut-and-bolt fixing, it suits thicker panels and applications where the holder may be removed and reinstalled during maintenance. The supplied hex nut tightens securely without marring the panel finish.
Typical Applications
- Industrial control cabinets subject to vibration
- Portable test instruments and field equipment
- Marine and off-highway vehicle electronics
- Power supplies shipped by long-haul logistics
- Any environment where a snap-in latch could loosen
How to Choose Between R3-54A and R3-54B
| Feature | R3-54A (Snap-In) | R3-54B (Screw-Lock) |
|---|---|---|
| Mounting | Spring latch, press-in | Threaded body + hex nut |
| Best for | Static panels, low vibration | Vibration, shock, repeated service |
| Installation time | Fast push-in | Requires spanner for nut |
| Panel removal | Tool-free push-out | Requires nut removal |
If your assembly line favours fast press-in installation and the end equipment sits in a stationary cabinet, the R3-54A will serve. If vibration or service reliability is the priority, the R3-54B is the safer pick.
Datasheet
[Download R3-54B specification sheet (PDF)]R3-54B 5x20mm Panel Mount Fuse Holder
FAQ
What is the difference between R3-54A and R3-54B?
They share the same electrical ratings and dimensions. The R3-54A uses a spring snap-in latch; the R3-54B uses a threaded body with a hex nut for bolted fixing.
When should I choose the screw-lock version?
Choose R3-54B if your equipment experiences vibration, shipping shock, or repeated removal during maintenance. The nut fixing does not loosen under lateral load.
What are the electrical ratings?
10A at 125VDC and 6.3A at 250VAC, with a 50A interrupt rating.
What panel hole size is required?
A Ø12.7mm hole. The 16.0mm front bezel covers the cutout.
How deep is the holder behind the panel?
30.5mm body depth; 38.6mm overall length including terminals.
Is the housing flame retardant?
Yes, the PBT body carries a UL 94 V0 rating.
Do both versions accept the same fuses?
Yes, both accept standard 5x20mm glass or ceramic cartridge fuses.
