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Comment by 112233 | Hacker News Reader

Why would you need a fuse in the plug? What purpose would it serve?

(edit) as correctly pointed out in the reply, fuse in brittish plug is because of peculiar way brittish homes are wired. Putting fuse in type F sounds weird.

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It's a theoretical benefit even with radial wiring, I think, for some smaller devices. A lamp that's designed to draw an amp will have a small, low-current flex which will fail before the main circuit breaker trips (while a 3A fuse would have protected it).

In reality I don't think it matters, and even on a ring main the MCBs often trip before the device fuses blow these days.

You could always include those inside the devices. No need to have them in plug. Probably would be even better. Replacing such fuse would also lead to checking what was wrong with the device.

If you have the fuse inside the device, then damage to the cable could cause a short circuit and potentially start a fire. Having the fuse in the plug means that a short circuiting cable will just blow the fuse in the plug instead.

That's why the other end has MCB/RCBO/AFDD.

Harder to catch is overheating due to overload or degraded contacts or wires (soviet aluminum wires, oh yeah).

In case of brittish ring circuit, there is added fun case of ring disconnecting in the middle, effectively halving cable cross section

In the UK (and some former colonies) houses were wired differently to save on copper making fuses in plus necessary.

https://en.m.wikipedia.org/wiki/Ring_circuit

> The reduced diameter conductors in the flexible cords connecting an appliance to the plug intended for use with sockets on a ring circuit are individually protected by a fuse in the plug

It sounds like the appliance cord is the driving factor for the fuse.

It was for the odd ring topology they have. The fuse in type F was sarcasm, as this is unnecessary. Although some plugs in China, used for boilers and aircos, do come with one or a resetable fuse.

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