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I found unused cables at home and I connected them:

PoE killer

This is obviously made as a joke, but I keep wondering what would happen if I were to actually plug both ends in my computer. Is there some safety where I would only toast my network port? Would my computer puff out in an expensive pyrotechnical display? Would the cable melt like butter in the sun? For some reason I am not keen to actually trying it out.

This is in Europe as the plug shows, and in my country the wall outlets can draw up to 16A.

Guillaume
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    As we don't know how things are connected inside, it's actually impossible to know. But it's certainly not a good idea to try it. Nothing in the way of useful functionality can result. – Chris Stratton Oct 12 '20 at 19:38
  • either you'll damage something or you wont. "RJ45" plugs are not designed to work with mains voltage, if the maind voltage hits the ethernet trasformer windings it will burn them up but the teansformer isulation can witstand over 1000 V ... unless damaged by the burning windings... – Jasen Слава Україні Oct 12 '20 at 19:47
  • What happens depends on how the wires are connected, and if it is a PoE device or not. We can't know how the cable is built and to what device you would be connecting it, so you must describe it. It also depends if the transformer has DC coupled termination between pairs or not. – Justme Oct 12 '20 at 20:00
  • Unless it is AC coupled with X rated caps, transformer goes poof. Looks like a feeble attempt to try Ethernet over line... not valid.... – Tony Stewart EE75 Oct 12 '20 at 20:10

1 Answers1

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Ethernet ports typically have an isolation transformer inside them that have an isolation rating of a few kV.

Depending on how the cable is wired, it will either do nothing, or it will destroy one side of the transformer wiring.

Other than burning out the transformer, the rest of the computer would likely be unharmed.

The transformer is likely to be the thing that burns out first rather than the actual cable because it probably has smaller gauge wires, and they are all packed together, which is much worse from a thermal perspective.

user4574
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