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Why does overload dissipate so much heat that it causes fire

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Advanced Member level 2
Apr 17, 2011
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We often use an "extender" to be able to connect multiple plugs to the same socket in the wall. This is just a plug with a box having space to connect multiple plugs. At other times we may use an extension lead.
If we connect a load of high power equipment, it creates an overload which can even cause fire.
Heat is dissipated when there is resistance in the flow of current. Resistance also exists in wires but at a very small amount. When an overload occurs precisely what part of the whole setup dissipate such much heat that the extender or extension lead may catch fire?


EVERY part in your extender that carries current dissipates power: P= I * I * R

Twice the current makes 4 x power.

Maybe it is a bad connection or may it is the sum of all heated parts that causes fire.

Buy a high quality one. The cost is less than building a new house.


I being an engineer myself take precautions. I was just asking for common knowledge.

I being an engineer myself take precautions. I was just asking for common knowledge.

Your problem was solved by Edison in ~1890. He designed a FUSE to prevent overheating anything in all installation due to overload current.

Keep all contacts in a good state and read the labels indicating a maximum rated current.
Overloading is simply not permissible in a safe system.

In one song it was said" who puts nails in place of fuses, he will start building a new home".

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