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can you hook the neutral directly to the live wire?

can you hook the neutral directly to the hot  wire? safely?  if it is not safe, why is it safe to hook the hot and neutral to the primary of a transformer?

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The transformer is made up of many windings of wire wrapped around a metal core (usually some sort of iron derivative) and that forms a coil. It is pretty common knowledge that when you feed DC to a coil that is wrapped around an iron core, you create an electromagnet (magnetism is what makes a transformer work). What is not so commonly known is that when you feed alternating current (AC) to any coil, the coil will try to resist any change in that current. If the coil is designed to work at a certain frequency, in this case either 50 or 60 Hz, it will present as a resistance which will limit the current through the wire of the winding. In a coil, this is called impedance, a function of inductive reactance. In addition, wire has a small physical resistance per foot, so for the length of wire used, there is a physical resistance, but it is the impedance/inductive reactance that is at work here.

Your wire loop has virtually no reactance and presents a short circuit, even if you have the same length of wire as would be found in the primary of a typical transformer. Therefore you are allowing the "full" current to flow unimpeded which will trip the breaker or blow a fuse.

Qa

Yes, but put a short circuit on the secondary, and the fuse will still blow on the primary.
Re-design5 years ago
It is never save to hook the hot and nuetral unless there is some resistance between them. The neutral eventurally connects to the ground so you would be connectening the hot to the ground which would never be a good thing. Regardless what the best answer says!!!!!!!!1
FoolishSage5 years ago
As I understand it the rule is that you need some sort of resistance between the two wires. If you don't have any significant resistance then the current spikes, throwing the breakers at best, melting circuits at worst.

I suppose that either there is enough resistance in the primary or there is another source of resistance in the circuit.
deadlift1979 (author)  FoolishSage5 years ago
hmm..Im curious as to where there is enough resistance in the primary...I cant imagine taking the windings and unwinding them hooking them to power and not blowing any breakers... but how does it not blow a breaker on an unloaded transformer?
Even a conductor offers some resistance. Enough length of a conductor might be a significant enough resistance but the EM field generated by the coils also affects the resistance. See the answer by Quercus for a better explanation.
lemonie5 years ago
What are you talking about / why would a person do that?

L
deadlift1979 (author)  lemonie5 years ago
seriously I am just curious... this is a hypothetical question
I don't understand the question.

L
rickharris5 years ago
NO
With a transformer you have almost an OPEN circuit, if there is nothing connected to the otherside.

Hooking live to neutral, with no load, is a certain way to blow the fuses in the circuit, because there is a very low resistance path for current.

Steve