What fuse should be used for a 750w electric iron connected to 240v supply? A: 3A b: 5A c: 10A d: 1A


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Oddman answered
750W/240V = 3.125A
A 1A or 3A fuse would be too small. If the fuse is in the iron, a 5A fuse might be appropriate.
The correct size of a fuse depends on what the fuse is intended to do. In house wiring, the fuse is intended to protect the wiring and to reduce the risk of fire. So, the fuse rating is determined by the wire size. Larger diameter wiring is allowed (by the electrical code) to have fuses with a larger rating. The electric iron of this problem might be plugged into a 10A circuit, that is, one protected by a 10A fuse and wired with wire appropriate to that rating.

When a heating element is involved, as with an incandescent light, an iron, or a hair dryer, choosing an appropriate fuse is more difficult. That is because the heating element draws more current when it is cold. In the case of a light bulb, the "cold" current can be 10-12 times the steady-state operating current. Even a 5A fuse may be too small for the iron, given this consideration.

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