High Voltage Leakage Question

Theoretically yes you can transform voltage from any current carrying cable, but-

1 Practically it is very difficult to put a loop very close any HT cable in a safe manner.

2-produced voltage is going to be very miniscule in magnitude as loop is going to be air cored

3 and what ever you get from it is finally going to load you HT line as soon as you put a load on it.

So in my opinion it's better to leave it,

Yes it can be good idea for an emergency mobile charger, provided you have done lot of fishing before.

This has been done before, typically a long time ago by farmers whose land the cross-country lines traversed. It is theft and is illegal and punishable. The magnetic field is there, but if you build a transformer taking advantage of that field, conservation of energy says that any power delivered to a load is that much power less delivered to the power company's customers. If it's a light load, like an electric fence to keep your livestock in, they likely won't see that, but if you're trying to get more it will be visible because instead of a winding on the ground under the line you would need to be very close to the high tension line: not advisable either legally or health-wise. By the way, all this is based on the magnetic field surrounding these wires, and the magnetic field is proportional to the current. The current is not huge - the whole point of high tension is to step up the line potential and minimize the current, to minimize line losses. The current on these cross-country lines is on the order of one hundred amps, which is not that different from the main breaker in your home. So don't think that because this is a 100 MWatt cross-country line that there is lots of free energy there; you can't get at it using magnetics (transformers).

Guest OP here

Please don't assume malice where ignorance will fit. My question was because there is no known insulator other than proximity for magnetic force. It simply seems there must be tons upon tons of lost energy radiating from HT lines. And IF there were this tremendous loss, why could it not be harnessed instead of wasted.

From what your telling me, it may be EMF potential, but if tapped, diverts the current from it's intended path. i see.

Radio stations expel megawatts per day into the air with the intension of being recieved so why would i want to steel electricity?

No energy is lost radiating from high tension lines until you try to drive a load with it. There is a major difference between the quasi-static fields around a 60 Hz high tension line and the fields radiating from a broadcast transmitter. See my detailed discussion of the difference at http://cr4.globalspec.com/thread/27322/electronics. It is reply #2.

I know I should be logged in, coronacameraman I am.

There is an electric field (due to voltage) around the powerline which can create corona (blue glow and sizzling) when the electric field intensity exceeds the breakdown strength of the air surrounding the powerline. There can be negligible current flow at full voltage. This field can light a florescent light bulb held by a utility worker in proximity of a transmission voltage powerline.

The magnetic field (due to current flow) in the powerline can exert a tremendous structural pull on magnetizeable materials. To create a transformer you need core iron, for an electric motor or generator you need "back iron" in the stator.

So just dangling a wire under a transmission line there will be a potential along the length of the wire due to the electric field intensity.

If you put numerous coils and iron in the proper configuration you can get an induced current to a load on the secondary of the transformer.

As mentioned it is illegal, and you can expect to pay for all energy stolen.

On a different vein, a tree has a difference of potential across it's height, even when there is no powerline nearby. I believe the generation of tree power is being patented, so you better get some while you can !

Persons who have used tuned antennae to "pinch" power radiated from nearby broadcast transmitters in the UK have been successfully prosecuted for theft.

Just because one could do something doesn't mean that one should.