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.
Incorrect. The neutral wire is a current carrying conductor and will generally be just as “hot” as the hot wire.
Okay fine, I’ll jump in. The neutral will carry the same amperage as a hot in a circuit. When you add yourself to the circuit accidentally, your resistance and the resistance of the intended load will divide up the voltage relative to your resistances. But the same amperage will flow through each of you assuming no other electrical pathway exists.
Image being confidently incorrect in the comments of a confidently incorrect post.
Under normal circuit conditions, the only voltage present on Neutral would be whatever voltage loss is occurring between the load and the tie in point between neutral and earth.
Different circumstances are different. Neturals are current carrying conductors. Neutrals are also grounded (as in bonded to ground at the main panel). In the case of someone wiring a recepticle or making joints in a junction box without turning off the circuit, one side of the neutral will almost certainly become disconnected from its return path in that process. When doing electrical work you absolutely do not consider the N wire safe for this reason.
Sure, if you touch the N lug in a hot panel or the N side of a receptacle while everything’s properly wired you won’t get shocked, but nobody has any reason to touch the N conductor if you aren’t working working on the circuit/box/panel. I’ll admit my use of “generally” above isnt exactly appropriate when you consider that a home doesnt “generally” have someone working on the wiring. Similarly my “incorrect” at the comment above me is less than 100% accurate, but I maintain that in the case of actual electrical work being done (the only time this conversation matters) you can never consider N to be safe.
All circuits are hot. All guns are loaded. All knives are sharp.
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.