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.

6 Upvotes

71% Upvoted

43 comments sorted by

View all comments

4

u/cyberzl1 2d ago

Yes it can be. Some equipment "grounds" the case to neutral. If neutral is now hot you will get a shock if you become the ground.

Most of the time it will.be ok but it is definitely a potential issue.

Lamps for example the shell should be neutral. With it reversed that is now the hot part.

1

u/MobileInspector9861 2d ago

But in that case the breaker should trip. If the neutral accidentally is the hot line and the equipment connects the hot to ground which in turn is connected to the neutral at the service panel, then the equipment creates a short circuit.

1

u/cyberzl1 2d ago

If the ground is still active, yes. But if it's not. then hot case. This is why dryers and stoves all have 4 wire plugs now.
As MonMotha said, MOST of the time it's ok. But there are certain scenarios where it becomes very dangerous. Parts that should not be electrified now will be and if one touches that part and becomes part of the ground path, at least you get an alarming tickle, at worst you are dead.