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Lights Supplied by 30 Amp Ring Final. B.S. 3036 Fuse.

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HellOOOoooo All,


I came across a strange one today. I went to change a faulty touch dimmer switch for an ordinary light switch. I discovered that the two lights controlled by the switch did not originate at the lighting circuit, but from a 30 Amp wire fused ring final. The supply was connected to an old metal double socket box below the light switch, in an added conservatory, with a blank plate over it. I can not add a fused connection unit as the box is a double socket box. The blank plate is covered by a small easily removed panel convector heater. I was considering installing an inline fuse holder in the double socket box for the lighting circuit. The lamps are low energy types so overloading is very unlikely, but faults may occur.


Thoughts please.


Z.
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    The traditional inside out squirrel cage induction motor ones actually draw less current when stalled than when spinning, so a fuse will not do much. The problem is that even with the lower current there is then no cooling airstream so it overheats.

    Modern ones are supposed to have a thermal fuse or trip in the winding bundle, presumably not all do.

    With electronically driven  DC brushless motors, who knows how it is done, as many methods as designers. However, a fuse would need to be set a lot closer than 3A to prevent a fire - the 25watt soldering iron is enough in the wrong situation.

    M.

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  • 0
    The traditional inside out squirrel cage induction motor ones actually draw less current when stalled than when spinning, so a fuse will not do much. The problem is that even with the lower current there is then no cooling airstream so it overheats.

    Modern ones are supposed to have a thermal fuse or trip in the winding bundle, presumably not all do.

    With electronically driven  DC brushless motors, who knows how it is done, as many methods as designers. However, a fuse would need to be set a lot closer than 3A to prevent a fire - the 25watt soldering iron is enough in the wrong situation.

    M.

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