Plugs = fire risk?

[El D]

Saw a question that got me thinking - are plugs left on overnight really a fire danger? How does the process work - does the plug fuse blow then the wires catch light? Why would it blow? Is it a risk if the switch is off or does it need to be out of the socket?

[qapmoc]

The thing which might be a problem under any circumstances is if you do something like use a 13amp plug with a 13 amp fuse and connect it to a large load such as a fan heater but only use 5 amp cable to connect it and then leave the cable in contact with something inflammable.

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[qapmoc]

...cont

Normally the only part of a system which might cause problems (in a modern correctly wired house) is likely to be a transformer in a power supply to a peice of equipment and even then it is 99.9% sure to cause no problems even if it overheats or something.

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[qapmoc]

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If you live in an old house with obsolete wiring which should have been changed years ago and you have loads of adaptors with many plugs into one socket then you might be asking for trouble just by the fact that you might be overloading the sockets which will get hot eventually and if the adaptor you have used is a 29 pence Chinese special cheapo model then it might be made from inflammable plastics.

[burnhal]

A fuse is a safety device. Basically any equipment connected to a load takes a certain amount of current safely under normal usage. If that current increases - perhaps due to a short circuit or a component failure in the piece of equipment then the fuse blows. A fuse blowing in a plug is effectively the same as switching off the socket- it removes the power source. So -no- the wires cannot catch fire when the power supply is removed!! However if a fault occurs in a piece of equipment whereby it overheats it is possible for a fire to occur before the fuse blows. This harks back to years ago when electrical equipment was not as safe as today and it was recommended to unplug overnight- back then most sockets were of the unswitched variety.

[Mungo jerry]

Part of the problem I think is that is a spark/ surge occurs then something may catch light, Yeah, the fuse is a safety device to break the circuit if over loaded.