R3-12E Bakelite 5x20mm Panel Mount Fuse Holder
Bakelite-bodied 5x20mm panel fuse holder, 10A 250V AC/DC, 50A interrupt. Knurled screw cap, UL 94 V0 phenolic body, phosphor copper terminals, 3000VAC hi-pot. Heat-resistant industrial fuse socket for power supplies and control panels.
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R3-12E Bakelite 5x20mm Panel Mount Fuse Holder
Why Choose a Bakelite Fuse Holder?
Most modern 5x20mm fuse holders use PBT or nylon engineering plastics. The R3-12E takes a different route. It uses bakelite (phenolic resin) body material instead. Engineers who know this material appreciate its exceptional heat resistance, its dimensional stability under sustained load, and its natural resistance to tracking on the surface.
Bakelite does not soften at the temperatures where PBT begins to deform. Consequently, the R3-12E suits applications where the holder sits near heat-generating components or runs near full rated current for long periods. It also looks the part: the knurled screw cap with the “FUSE” marking gives a classic industrial appearance that engineers recognise and trust.
Electrical Ratings
- Fuse size: 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
- Dielectric withstand: 3000VAC
- Contact resistance: <5mΩ
- Insulation resistance: >100MΩ
Mechanical Dimensions
The front bezel measures 15.0mm across, and it carries a knurled screw cap for tool-free fuse replacement. The threaded body screws through a Ø12.6mm panel hole and locks with the supplied hex nut.
Overall height from the cap top to the terminal end is 36.9mm. Behind the panel, the threaded section extends 21.5mm. The solder lug measures 4.0mm wide with a 2.0mm hole; alternatively, a straight PC pin version is available for through-hole soldering.
Construction Highlights
The knurled cap twists off by hand. Therefore, maintenance crews can swap a blown fuse without a screwdriver. Meanwhile, the bakelite body stays cool to the touch even after prolonged operation at rated load.
Phosphor copper terminals grip the fuse ends with a consistent spring force. As a result, contact resistance stays below 5mΩ across thousands of insertion cycles.
Where Engineers Deploy It
- Linear power supplies and transformer-based equipment
- Industrial control panels in high-temperature enclosures
- Test and bench instruments where frequent fuse swaps occur
- Traditional OEM equipment that specifies phenolic hardware
- Legacy equipment replacement where bakelite holders were originally fitted
Datasheet and Ordering
[Download R3-12E specification sheet (PDF)]R3-12E Panel mount fuse holder
Standard configuration ships with screw-type solder terminals. If your board design calls for straight PC pins, or if you need tin-plated terminals, please specify when you send your RFQ.
FAQ
What makes the R3-12E different from other 5x20mm holders?
Its body is made of bakelite (phenolic resin) rather than PBT plastic. Bakelite offers better heat resistance and dimensional stability at elevated temperatures.
What are the electrical ratings?
10A at 250V AC or DC, with a 50A breaking capacity.
How do you replace the fuse?
The knurled screw cap twists off by hand. No tools are required for fuse replacement.
What panel hole is required?
A Ø12.6mm mounting hole. The front bezel is 15.0mm in diameter.
Is bakelite really UL 94 V0?
Yes. The phenolic body carries a UL 94 V0 flammability rating.
What terminal options are available?
Standard units come with 0.5mm phosphor copper solder lugs. Straight PC pin terminals can be quoted on request.
How deep does it sit behind the panel?
The threaded section extends 21.5mm behind the panel; total height is 36.9mm.
