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by UebVar 110 days ago
I disagree. The plug is usually part of an appliance connector cable, that has no idea what happens to be on the other side aswell. If you size that cable for the same current as the socket, the cable itself is protected by the circuit breaker.

The correct spot for the fuse is the appliance itself. Fuses used to be easily replaceable, often with fuse holders [1]. I have, however, never seen a computer with one.

[1] https://uk.farnell.com/productimages/large/en_US/4578676.jpg

2 comments

There's simply never a reason for a user to replace a fuse in a properly designed device. If a fuse blows then it means something has gone horribly wrong and replacing the fuse won't fix it.

The exception would be a device that sends mains more-or-less directly to a user device, then a fuse would be protecting against a fault in the user device and should be replaceable. A lamp that takes a regular light bulb would be a good example of this.

Replacing the fuse alone won't fix it. But it at least gives you a chance to be able to fix whatever the underlying cause actually was.
True, but in that case the fuse only needs to be as easy to replace as whatever else you're replacing. If there's internal socketed components then the fuse only needs to be internal and socketed. If everything is soldered to a board then it's fine to have the fuse soldered too.

Many older appliances did expect the user to put some external bits in that would be across mains, or maybe across a transformer to mains, and in that case the fuse was just as replaceable as the user-provided part.

The fuse in the plug comes from a history of not wanting everything to blow up in the face of "I spilt my tea into the toaster". Very simple device, probably fine once it's dried out.

But really the value of having the fuse in the plug is that if it blows, the live wire in the cable is definitely disconnected all the way to the wall, so whatever has happened you know as best you can that it's not in a state where it could still get worse.

Most computer PSUs have a fuse inside, and it is quite easy to replace them.

I know because many moons ago I blew one, in the era when PSUs had a toggle between 120V and 230V, and I set it to 120V in a country that runs at 230V...