Installing hot wire

[Bruce]

Dead end is fine, normal actually. The circuit is completed when something touching the ground (*) is also touching the hot wire. If you live somewhere really dry, or where the ground is frozen in the winter, the ground is not a great conductor. I've carried a ground wire 6" below the hot wire on my fence. The posts (steel T-posts except at corners and gates) are 5' out of the ground, the fence is 4' woven wire and the hot runs on top at 5 '. I do not currently have hot wire running over the gates other than the one at the north end of the barn. The hot wire wasn't installed yet when the picture was taken but the energizer is inside between the open door and the closed big doors. The hot wire runs from the right side of the barn overhead to an extension on the right gate post and the gate and the section to the left are just a short run of wire. The main run goes the other way. Note that the red line denotes the "fenced" area, the hot wire stops at the corner of the small barn and there is a gate between the barns on the right. It isn't protected with hot wire and that does concern me.



Note carefully that in @Latestarter's diagram, the energizer is on the left side of the picture. You REALLY don't want the free end of the gate wire to be hot when it is disconnected. As you can see they have a "two way gate anchor" on both posts but the hot wire is connected only to the one on the left. You don't really need a "two way" on the right side, you aren't going to connect anything to the second side if you run the hot wire underground as shown.

BTW I just saw this thread. I wouldn't have ever guessed someone would run 120V straight to the fence wire

* "Ground" is either the actual ground or the metal fence that is clipped to the metal T-posts in the ground.

 

[greybeard]

The circuit is completed when something touching the ground (*) is also touching the hot wire

Not, until the pulse actually returns to and reaches the negative terminal on the circuit board back at the energizer! Either thru the animal, along the Earth ground path, up the ground rod, into the clip and thru the lead insulated wire back into the charger, or along the negative wire(if it's a 2 wire system) and back into the energizer. Either way, the pulse must reach the neg term on the board before the circuit is complete and a shock is felt.

(On a dead end fence, don't be surprised if you find higher voltage near the end than at the beginning or middle of the fence...electron build up)

 

[Hipshot]

Well actually you can hook 110 to a fence if you use a pulsating rectifier. But it is in efficient . The difference between it, and using a fence charger with a step up transformer ( this is simplified ) is the difference between getting hit with a tack hammer and a sledge hammer .I don't have the specs on voltage supplied by a solid state modern fence charger, but it is far greater than 110 volts .It is the pulsing current that makes electric fencing safe to use. It really functions very similar to the ignition system on a gas engine .And that spark plug is getting a lot more than a 110 volts too . I been bit by both The number one rule of electric fencing is DON'T TOUCH IT won't tell you the second rule TSC has a very good store display that makes it simple . But there are so many options these days sure has changed over the years .

 

[greybeard]

I don't have the specs on voltage supplied by a solid state modern fence charger, but it is far greater than 110 volts .

At minimum, it would be 50x (or more) what 110v house current puts out.. (IN VOLTAGE!). 5500v would be the least I'd want on a good fence.

 

[babsbag]

If I have a gate between pastures and I am not worried about my dogs going over it I run my hot wire overhead. Usually it is because I need that hot wire elsewhere, not because I am protecting that section of fence. I take those step in fiberglass poles and fasten them to each side of the gate and run the wire up one side, over the top, and down the other side. Of course if you have a tractor with a roll bar you need to go HIGH.

 

[babsbag]

At minimum, it would be 50x (or more) what 110v house current puts out.. (IN VOLTAGE!). 5500v would be the least I'd want on a good fence.

I have a digital tester and it reads up to 9.9 kilo volts. I am not happy unless it says 7 or better.

 

[Bruce]

Not, until the pulse actually returns to and reaches the negative terminal on the circuit board back at the energizer!

True, though that pulse happens every second right? So for practical purposes, pretty much any time the hot wire is touched at the same time as anything that can connect back to the ground terminal.

I've run conduit and insulated wire under the gates so I don't have to worry about overhead wire ... other than where the wire comes out of the barn from the energizer. TOO many buried rocks.

 

[mystang89]

This is the one I bought. I think it said it pulsated at a 2 sec delay but can't double check at the moment. I'll be using steel quite and not the poly wire to run up top. If I don't have to bring another wire down the bottom of the fence them I'll probably just run the wire underground below the gate.

 

[greybeard]

True, though that pulse happens every second right?

The time period between pulses varies with different energizers, as does the length of the pulse itself. (duration and frequency) .
This is part of the formula for determining the energy (joules) rating.
The frequency is closer to 2 second intervals, but the duration of the pulse is very very short. A few ten thousandths of a second. That's .000?--probably less than .0005 seconds. Doesn't take long, as the energy is stored in capacitors and electrons on the conductor are being knocked off their atoms at near light speed.

.I don't have the specs on voltage supplied by a solid state modern fence charger, but it is far greater than 110 volts . It is the pulsing current that makes electric fencing safe to use.

And, the much lower current used in fence chargers. It's in milliamps as opposed to a higher current in even half wave rectified AC household 110.
Rectified AC is still pulsed or 'rippled..how much depends on whether it is 1/2 wave, full wave, or bridge rectified. (1, 2 or 4 diodes) 1/2 wave results in there being zero voltage during 1/2 the one second time period (time is important in calculating energy or Joules) Full wave uses both sides of the sine wave and produces voltage all the time, and IIRC, that means a pulse rate that's very high (approx 240 ripples per second) but much lower voltage output. Current is load dependent.

I did once calculate what an automotive parts setup would produce on a fence and was dismayed at the joules rating. Output voltage was 'interesting'.... Around 38,000 volts, but joules was fraction of 1 joule. Life of the system would be prohibitively short and input energy to drive either a distributor or flywheel for CPS usage.
Even using the flywheel, & coil off an old lawnmower engine was way too inefficient because you still had to have a motor to drive it..

 

[Mike CHS]

GB - That is one of the better explanations I have seen for that topic.

I don't understand all the science behind the chargers but I do know that my 75 mile charger will lay a person on the ground when/if they touch the high hot and ground wire.