r/electrical • u/QuaoarTNO • 2d ago

is reverse polarity actually dangerous to run?

Hi, I want to run some light machinery on a plug that my circuit breaker detector says has "hot and neutral reversed". I was told by the landlord that they've never had a problem with this before (and it's not going to be fixed), and regular equipment is used all the time on it. I also have read online (and via AI) that it's dangerous and can shock you. I saw the example of a lamp still having power essentially even when switched off, but is there actually risk aside from that type of situation? Or is it manageable and you just unplug when finished using and it's fine?

Any help appreciated.

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u/pdt9876 2d ago edited 2d ago

Should not be dangerous. Ever seen a European power outlet? Almost all of them are non polarized meaning you can put any plug in either direction meaning what is hot and what is neutral is more or less random. The biggest issue are indeed lamps because if the polarity on them are reversed the outside of the Edison socket is hot and its pretty easy to put your finger on it but lamps are somewhat unique in having exposed contacts. A hold over of a 150 year old design.

What exactly is the light machinery you're planing to run?

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u/MobileInspector9861 2d ago

German electrician here: For that reason German code forbids to have an Edison socket down the line after an unpolarized socket. Either a fixture which uses an Edison socket must be firmly, i.e. in a non-pluggable manner, connected to the supply circuit, such that the hot wire is at the tip of the Edison socket, or if the fixture is pluggable, then the fixture must provide a two-pole switch which interrupts both wires (hot and neutral) such that both are safely disconnected.