R3-12 5x20mm Bakelite Panel Mount Fuse Holder (Round Hole Terminal)
Bakelite 5x20mm panel fuse holder with round-hole solder terminal, 10A 250V AC/DC, 50A interrupt. M13 thread, knurled “FUSE” cap, UL 94 V0 phenolic body. For wire soldering and ring crimp connections. Compare with flat-blade R3-12E.
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R3-12 5x20mm Bakelite Panel Mount Fuse Holder (Round Hole Terminal)
Quick Answer: What Is the R3-12?
The R3-12 is a bakelite-bodied, screw-cap panel mount fuse holder for standard 5x20mm cylindrical fuses. It carries 10A at 250V AC or DC and interrupts up to 50A. Its key identifying feature is the round-hole solder terminal: a 13mm diameter lug with a 1mm hole for wire termination.
R3-12 vs R3-12E: Which Terminal Do You Need?
Both models share the same bakelite body, M13 thread, knurled cap, and electrical ratings. They differ only in the terminal style:
| Feature | R3-12 (This Page) | R3-12E |
|---|---|---|
| Terminal shape | Round hole lug, Ø13mm, 1mm hole | Flat blade, 4.0mm × 2.0mm, 0.5mm hole |
| Best for | Wire soldering, ring crimp terminals | Faston tabs, push-on connectors |
| Mounting thread | M13×P1 | M13×P1 |
| Front bezel | 15.0mm | 15.0mm |
| Overall length | 36.3mm | 36.9mm |
Pick the R3-12 when you plan to solder a wire directly to the lug or fit a ring crimp terminal. Choose the R3-12E when your harness uses flat Faston connectors that slide onto a blade.
Full Specifications
- Product model: R3-12
- Fuse size accepted: 5 x 20 mm cylindrical
- Rated current: 10A
- Rated voltage: 250V AC / DC
- Breaking capacity: 50A
- Body material: Bakelite (phenolic resin), UL 94 V0
- Terminal material: 0.5mm phosphor copper
- Terminal style: Round hole lug, Ø13mm, 1mm hole
- Mounting thread: M13 × P1
- Panel hole required: 12.7mm (M13 thread)
- Front bezel diameter: 15.0mm
- Knurled cap: Yes, hand-tighten, marked “FUSE”
- Dielectric withstand: 3000VAC
- Contact resistance: <5mΩ
- Insulation resistance: >100MΩ
- Overall length: 36.3mm
- Body behind panel: 20.5mm
- Cap depth behind bezel: 8.5mm
Why Engineers Specify Bakelite
Bakelite withstands sustained heat better than engineering plastics. It does not creep under clamping pressure, and its surface resists tracking and carbonisation. Consequently, the R3-12 remains dimensionally stable even when mounted near transformers, heat sinks, or power resistors.
The knurled cap twists off by hand. Therefore, field technicians can replace a blown fuse without tools. The “FUSE” marking and directional arrow on the cap indicate correct fuse orientation.
Typical Applications
- Linear power supplies and transformer-fed equipment
- Industrial control panels in warm enclosures
- Bench test instruments
- Legacy equipment repair and replacement
- Any circuit where a round-hole solder lug matches the existing wiring harness
Datasheet
[Download R3-12 specification sheet (PDF)]R3-12 Panel mount fuse holder
For flat-blade terminals, see the related model: R3-12E.R3-12E Panel mount fuse holder
FAQ
1.What is the difference between R3-12 and R3-12E?
A: Both use the same bakelite body, M13 thread, and 10A 250V ratings. The only difference is the terminal. R3-12 has a round-hole solder lug (Ø13mm, 1mm hole). R3-12E has a flat blade terminal (4.0mm × 2.0mm).
2.What size fuse does the R3-12 accept?
A: Standard 5x20mm cylindrical glass or ceramic fuses.
3. What is the current and voltage rating?
A: 10A at 250V AC or DC, with a 50A breaking capacity.
4. What panel hole size is required?
A: M13×P1 thread requires a Ø12.7mm panel hole. The front bezel is 15.0mm.
5. What is the terminal made of?
A: 0.5mm phosphor copper with a round hole for solder or ring crimp terminals.
6.How do I replace the fuse?
A: Twist the knurled cap counter-clockwise by hand. No tools required.
7. Is the housing flame retardant?
A: Yes, the bakelite phenolic body is rated UL 94 V0.
8.Can I use it for DC circuits?
A: Yes, it is rated for both 250V AC and 250V DC at 10A.
