Cause he's only got one wire =)
Seriously, probably something that's already there.
If it's naked wire this is a really bad idea cause you'll be electrifying the ground and that will do all sorts of weird things, you really need to specify exactly what you have on your hands. I go with Blueroom though, why not two wires? You could create a ground return point at either end and feed it into rods sunk into the earth but again this is electrifying your local ground and could have serious ramifications on local RF or power systems. If the wire you're trying to feed power through is naked (IE grounded) you obviously can't use a ground rod at either end for the return.
Ground is normally only used to establish a reference potential, rarely is it used to try and pass any meaningful current. The only exception I can think of was equipment used to provide cathodic protection of underground piping and that required quite expensive and extensive series of transformers and grid ground rods.
Transferring power takes at least 2 wires, real high power uses 3 wires (3 phase) as wire costs increase exponentially with current capacity.
I'll have to run some experiments with a 50' extension cord, using 120 vac, possibly through an isolation xformer. With 25Ω earth resistance I should be able to substantially light a small bulb. Driving a ground rod at the receiving end is probably the hard part. Deeper rod = brighter bulb?
I'll have to run some experiments with a 50' extension cord, using 120 vac, possibly through an isolation xformer. With 25Ω earth resistance I should be able to substantially light a small bulb. Driving a ground rod at the receiving end is probably the hard part. Deeper rod = brighter bulb?
Keep in mind that ground conductivity will vary with soil moisture levels which means seasonal variation, so any results you get will just be for one specific ground condition.
I am not sure how well that would work, but it would be interesting to see your results. The systems in your link were running in the KV range, so I wonder how well it would work in the infraKV range. Also did you see this part on the wiki article?
Regulatory issues
Many national electrical regulations (notably the U.S.) require a metallic return line from the load to the generator. In these jurisdictions, each SWER line must be approved by exception
As the ground varies in conductivity over a given area, higher voltages at higher available power levels become dangerous. Downed power lines that are still live can make walking on the ground anywhere at all near them very dangerous as the ground can develop large voltage drops at a high-resistance spot. THAT'S why regulating agencies would crap a toy hatchet if you tried using earth as a power conductor. Not only is it impractical, but it can be very dangerous.
Well I'm not an expert, but I can contribute this: Nikola Tesla, for his extremely high voltage experiments, used a huge ground rod system, wich he kept wet with a continuous water flow
So I guess, the ground is suitable for strange HV experiments and as antena for ultra low frecuency... but to light a bulb... better start collecting money, and buy the other wire
This is crazy he's going to electrify a tree ? he can't buy 15 metres of wire ? has this guy just escpaed a mental hospital by chance ? and its for his kids ? I can think of any number of very appropriate terms to desribe this individual but I'm sure they would not pass the forums word checker
Then again, if he can find a way to carry 400w over 750ft with one wire and not use gigavolts (or gigahz, lets say DC), hed be a very rich man in a short amount of time ;-).
he would be much better off using a solar panel, if this is outside and for kids 12-24 volts is all he really wants. this is one madman (and yes what a suprise a yank - with no offence to the more intelligent americans on here) that will fry his kids and then not be able to figure out how it happened because he's pretty close to being a mental case !