MF-527 5x20mm Panel Mount Fuse Holder with 1/2″-28UNEF Thread
Imperial-thread 5x20mm panel fuse socket, 10A 250VAC/125VDC, 50A break. 1/2″-28UNEF bush, PBT UL94 V0 body, phosphor copper terminals, 3000VAC hi-pot test, 47mm overall length. Drop-in replacement for legacy imperial panel cutouts.
Get a Quote
MF-527 5x20mm Panel Mount Fuse Holder with 1/2″-28UNEF Thread
Product Overview
Built around a 1/2″-28UNEF threaded mounting bush, the MF-527 is a screw-in panel fuse socket for 5x20mm glass or ceramic cartridge fuses. It carries 10A at 250VAC and 10A at 125VDC, and it delivers a 50A breaking capacity for fault isolation.
What sets this model apart is the imperial thread specification. Many 5x20mm holders rely on metric M12.5 threads; in contrast, the MF-527 uses 1/2″-28UNEF. This detail matters when your enclosure already follows imperial drill patterns. Moreover, it simplifies replacement of legacy equipment.
Construction and Materials
The insulating body comes moulded from PBT polybutylene terephthalate, and it carries UL 94 V0 flame-retardant certification. Current paths run through 0.5mm phosphor copper terminals. We select this material for its spring contact pressure and its resistance to fatigue over repeated fuse swaps.
Furthermore, the holder passes a 3000VAC dielectric withstand test. It also maintains insulation resistance above 100MΩ. Steady contact resistance stays under 5mΩ. As a result, on-state losses remain low, and derating under normal load rarely becomes a concern.
Mechanical Data
- Cartridge size accepted: 5 x 20 mm
- Mounting thread: 1/2″-28UNEF
- Panel hole required: Ø12.5 mm
- Front bezel diameter: 14.6 mm
- Overall length: 47.0 mm
- Body behind panel: 32.8 mm
- Nut engagement depth: 7.9 mm
- Terminal tab size: 11.9 mm × 12.5 mm
Where It Fits
Typical deployments include front-access power entry panels, bench instruments, medical device bays, and industrial rack enclosures. In these applications, an operator may need to swap a cartridge fuse with nothing more than a screwdriver. The threaded bush, together with the supplied hex nut and washer, clamps securely across thin sheet metal or thicker plastic panels.
Ordering Notes
Each holder ships with the threaded body, hex nut, and flat washer. We supply terminals in phosphor copper; additionally, we can quote tin-plated versions on request. If your assembly line needs taped leads or special packaging, please mention this during RFQ.
Datasheet
[Download the MF-527 specification sheet (PDF)]MF-527 Panel fuse holder
FAQ
Which thread standard does MF-527 use?
It uses a 1/2″-28UNEF imperial thread. This is the key difference from metric-thread alternatives such as M12.5 models.
What panel hole must I drill?
A Ø12.5mm hole accepts the threaded bush. The supplied hex nut locks the holder from the rear.
Does the holder accept both AC and DC loads?
Yes. Ratings are 10A at 250VAC and 10A at 125VDC, with a 50A interrupt rating.
Is the body self-extinguishing?
The PBT housing carries a UL 94 V0 flammability rating.
How long is the holder behind the panel?
Body depth behind the panel is 32.8mm; total length including terminals is 47mm.
What are the terminals made of?
Phosphor copper, 0.5mm thick. Tin plating can be quoted if required.
