cross-posted from: https://lemmy.nz/post/28693796
Check the comments of the original post for the stupidity.
For those of you without an electrical background, the diagram shows the protective earth connected directly to phase, with phase and neutral also joined.
Correctly wired, this would be a three pin plug, with the earth wire connected to the earth pin in the plug, with the other end connected to the metal casing of the appliance. This is a critical safety feature, which will cause the circuit protection to trip in the event a phase wire contacts the metal of whatever this is connected to.
If this was actually done, the most likely outcome is it would trip a circuit breaker, but if the neutral was broken, it would connect phase directly to the casing, and likely electrocute someone.
Isn’t the common used in three way circuits as a hot at some point? Been decades since I learned about those, so my memory is very vague.
Three phase circuits when perfectly balanced actually have no current on the N wire, which is kindof the exception to my “N wires are current carrying conductors” above, but very few scenarios in real life actually have perfectly balanced three phase loads. That’s kindof the opposite of what you were saying, but memory can be weird like that sometimes.
It’s also relatively common to use a white wire as your third hot for three phase circuits that dont have or need a N at all. The white wire isnt actually N in that case, but a layman with cursory knowledge of electrical work would look at the white wire with voltage to ground and say the N is hot. By the code you’re supposed to mark the white wire with colored tape in this scenario to indicate that it’s hot and not N.