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torker
11-21-2011, 06:01 AM
Hi guys! Figure someone here will know...
My place I bought out here...the power comes into the transformer outside...with just one wire???
I've looked around at lots of other ones in town here and they all have two wires.
What's up there?
Always thought you needed two...or more.
Thanks!
Russ

deltaenterprizes
11-21-2011, 06:11 AM
How old is the place? Sounds like you only have 110v, very old wiring and need an electrical panel upgrade.
Did you have the property inspected before you bought it?

torker
11-21-2011, 07:29 AM
Place is old...but it has 220V. The electrical is a new 200 amp serive....put in a few years ago. I also had the mast replaced when I bought it.
Just can't figure how it works with one lil' wire????

MotorradMike
11-21-2011, 07:31 AM
Hi guys! Figure someone here will know...
My place I bought out here...the power comes into the transformer outside...with just one wire???
I've looked around at lots of other ones in town here and they all have two wires.
What's up there?
Always thought you needed two...or more.
Thanks!
Russ

You're absolutely right, you need 2 wires to the transformer on the pole.
One of the wires is ground and you may have missed that one.

3 wires from the transformer to the house.

Don't go climbing up the pole to find it!

mike os
11-21-2011, 07:34 AM
Perhaps they have actually gone all modern & used one of them new fangled multi core cables.......only a few decades old, so you may not have them yet.:p

J Tiers
11-21-2011, 08:50 AM
The INPUT to the transformer is one phase of a three phase line...... it will come to a big insulator on top, at maybe 4160VAC.

The other INPUT wire is the neutral, and it is the same wire as your incoming neutral to the house. You may not notice it, but it will be running along about 4 feet from the high voltage. All the transformers will have a connection to it, but it is grounded, and may not be as visible to you.

One of your "drop wires" will connect to it. Follow the connections and you will see it go to the transformer. Pole transformers may have the neutral connection internal, and you won't see it unless you know it is the same as another wire.

Bruce Griffing
11-21-2011, 09:19 AM
I built a house several years ago that was 1/4 mile off the road. I had my own transformer located near the house. It was fed by a ~13kV line. That line was a single center conductor with a ground sheath - just like coaxial cable. At that voltage the line only needed to carry about 3 amps to provide my 200 amp service. The ground sheath is the return path.

Evan
11-21-2011, 09:26 AM
There are some power systems in Canada that use a single hot wire distribution system. The system is entirely single phase. The ground return "wire" is the actual earth ground. There isn't any aerial ground or neutral. The transformer secondary is centre tapped and provides the usual split phase 110-110 with neutral. The input to the transformer will be just one aerial wire and a ground wire that runs down the side of the pole to earth ground. These systems are hit by lightning a lot since they don't have an overhead protection ground.

http://www.ruralpower.org/

awemawson
11-21-2011, 11:44 AM
Round here most of the power distribution is overhead, and was 3 phase and neutral 415v as four separate uninsulated cables on poles and insulators. They've been going round replacing it with 'bundled cable' comprising four sheathed cables twisted together. Drops to feed houses use a 'concentric' cable comprising a central 6mm aluminium core, insulated, then covered in a copper braid which is also insulated as an outer sheath. The core is live 235v and the braid is neutral. It is rated at 100amp and I reckon it gets pretty hot at that. It may look like a single cable but is actually a pair of conductors.

Arcane
11-21-2011, 06:02 PM
It's exactly as Evan posted...we use earth return here in Sask extensively for single phase power. Used to be a bit of understrung neutral conductor in the rural areas (it's de rigueur in urban construction here) but almost all of that has been abandoned when they rebuilt the OH or went to underground cable. All our underground primary cables have a concentric neutral which is connected to earth at every termination point.

torker
11-21-2011, 06:22 PM
There are some power systems in Canada that use a single hot wire distribution system. The system is entirely single phase. The ground return "wire" is the actual earth ground. There isn't any aerial ground or neutral. The transformer secondary is centre tapped and provides the usual split phase 110-110 with neutral. The input to the transformer will be just one aerial wire and a ground wire that runs down the side of the pole to earth ground. These systems are hit by lightning a lot since they don't have an overhead protection ground.

http://www.ruralpower.org/
Yep...that's what it is then. There is a ground wire going from the transformer to the earth. Geez...I thought I was nuts...lol!
Thanks guys!

Russ

quasi
11-21-2011, 06:23 PM
Evan's dead right, and I am a Sparky.

jdunmyer
11-21-2011, 06:57 PM
When we drove through Sask on our way to Alaska, I noticed that single-wire distribution setup and marveled at it. Inquired when we returned home, and found that is indeed just what it appears: one hot wire, and the Earth as the return/neutral.

Probably brings up the earthworms at times!

armedandsafe
11-21-2011, 07:17 PM
Early 70s, working as irrigation machine design, install and maintain. 440VAC, 3 phase, 2 wire. Which meant we were always standing on one phase of the incoming. Usually on wet ground with lots of fertilizer in it. Real comfy feeling that is, doncha know.

Pops

914Wilhelm
11-21-2011, 07:41 PM
So.......don't you get a fair amount of ground resistance either at the end of a long hot dry summer or in the middle of a biting cold winter? Doesn't this create a voltage drop? My electric fences in Oregon need a seperate ground wire as during the summer in the dry soil there is not much oophmm left in the system after a 2000' run. Also, how do you get 110 off the system short of having your own transformer at the house? And if you had a transformer at your house to make 110, it's neutral would be 110 volts different than ground, wouldn't it?

jdunmyer
11-21-2011, 07:58 PM
914Wilhelm,
Follow the RuralPower link to see how you get the neutral.

darryl
11-21-2011, 07:59 PM
Saskatchewan is actually way ahead of the rest of the world when it comes to power distribution. They were going to go totally wireless ala Nikola Tesla, but they figured it would be too eerie for the general population, so they decided to run one wire anyway. The transformers are also just for show- at night they transform into tractors and pull haywagons full of party-goers to square dances. Those prairie people are more than just wheat farmers-

The Artful Bodger
11-21-2011, 09:04 PM
So.......don't you get a fair amount of ground resistance .......

Well yes but the Earth has a very large cross section so the resistance in the circuit is pretty much that at the two points where the earth rods go into the ground and the distance between them is much less significant.


Also, how do you get 110 off the system short of having your own transformer at the house? And if you had a transformer at your house to make 110, it's neutral would be 110 volts different than ground, wouldn't it?

A conventional transformer with a single secondary winding would give you two legs that have a voltage between them and nothing between either of them and ground, thats how isolating transformers are used. It is usual though to ground one leg and call that the neutral and the reason for doing that is so that the protective ground systems can work.

armedandsafe
11-21-2011, 09:56 PM
The Earth is a very large pool of electrons. The electrons entering the Earth at your work station don't have to flow all the way back to the generator. Because we are discussing AC here, the electrons just wander to the left for a fraction of a second, then back to the right for a fraction of a second.

Think of the Earth as a large pool of water. The generator is a pump. That pump sucks up water and presurizes the mains (wires) between it and your work station. From that moment on, all the generator does is suck up a little bit of the water in the pool (electrons in the Earth) and push them a little ways down the line. The it turns around and sucks that water (electrons) back, shoving it (them) into the ground. The motor in your workstation uses the movement of the water (electrons) to power its movement. The actual drops of water (electrons) in your motor don't have to travel all the way from the generator to your motor and back again on each pulse. In fact, there are electrons in your motor that will never actually get all the way out of your motor.

When having problems with our ground in dry weather, we would apply a 5 gallon bucket of water at the grounding point, with a cup of salt dissolved in it, once a month, which made a large difference. It might also eat your grounding posts out every few years. We could get 3 to 5 years on a ground post for the fences in Nevada, which is relatively dry.

Pops

Andrew_D
11-21-2011, 10:14 PM
As others have mentioned, Saskatchewan uses only one the "hot" wires...no ground, for their power distribution. Thought it was weird too at first...

Here in Manitoba, we use two wires (4 for 3-phase), but the system will still work if the ground wire is broken.

The wire past our house had a tree fall on it during an ice storm. The crew came out, fixed the hot line and left....they had too many calls to be bothered with the ground right then. I've heard that the power meter will read higher, but we never noticed a big difference. The crew came back about 1 month later and hooked up the ground line. (In this case, the transformer was still grounded into the earth.)

Andrew

Bob Ford
11-22-2011, 12:30 AM
We use a similar system in our area. One leg of a 15kv three phase circuit to a single phase transformer the other side of the transformer to ground. 120v. 240v output with a center tap grounded. For a three phase setup all three phases of the 15kv circuit are used.

Bob

mike4
11-22-2011, 03:11 AM
It's exactly as Evan posted...we use earth return here in Sask extensively for single phase power. Used to be a bit of understrung neutral conductor in the rural areas (it's de rigueur in urban construction here) but almost all of that has been abandoned when they rebuilt the OH or went to underground cable. All our underground primary cables have a concentric neutral which is connected to earth at every termination point.
A lot of our rural remote areas are fed with single wires and the system is as Evan described , many hunderds of miles of single phase wire and the ground is used as neutral , has some problems during periods of prolonged drought.
Michael

Evan
11-22-2011, 03:33 PM
We have the same situation here. As I live in central BC the communities are very widely spaced. We have single phase lines reaching as far as several hundred kilometres. Some of the branch feeders from those are one wire feeders. We sometimes have problems in the summer as some areas around here are near desert conditions. It also happens in the winter when the ground is frozen as deep as 10 feet. Frozen earth isn't a very good conductor either.

Single phase feeders of any significant length are very unreliable. The circuit we are on used to be single phase up until about 20 years ago. When I first bought a computer it was extremely annoying how often the power would drop or glitch. I kept a log over a year and took in to the local guys at the BC Hydro maintenance dept. They were friends of mine since I used to repair their office equipment ( yes, I know or knew nearly everyone in nearly every office in this town). My log showed about 230 dropouts in one year. I showed it to the engineer and he looked up their log for this circuit. He told me I must have missed a few since they recorded about 270 hits.

The great majority were marked as "bird on line" shorting the line on the 2 wire feeders. That is code for "we have no idea what caused it". They finally strung 3 phase on our circuit when the wires almost melted off the poles one year during an extended spell of -40 weather. When I asked about that I was told the the wires were sagging over a foot between poles due to heating. They nearly lost the entire circuit which at -40 would have been a Very Bad Thing.

I had business machines on villages at the ends of the one wire circuits and keeping them running was a challenge. Lots of lightning hits with occasional damage and plenty of power glitches enough to crash the machines. I brought in the company Dranetz Analyzer in one case to prove that the problem was't our fault at one of the distant Government Forestry offices. A Dranetz Analyzer is the power company standard for measuring line problems. The model Xerox had was about $8000 and it had its own battery backup with remote comms for reading over the phone line. It stopped answering after a few days so I went out to retrieve it. It had crashed somehow due to the very unstable power but not before it recorded many faults.

For Torker, make sure you have any costly electronics on uninterruptible power supplies to avoid damage. It won't prevent damage from a nearby lighting strike but it will take care of everything else.

Arcane
11-22-2011, 09:46 PM
Torker, if you are concerned about lightning strikes, have a look at your pole mounted transformer and see if it has a lightning arrestor mounted on it. Should look like this (old style)

http://www.supplierlist.com/photo_images/25338/lightning_arrestor_Y5C-24_Y10C-24.jpg

or this (new style)

http://www.supplierlist.com/photo_images/25934/Surge_arrester_YH5W-24_YH10W-24_.jpg
If it doesn't have one, call up the local Sask Power District office and get them to install one...they are supposed to have one but sometimes don't if it is a very old installation. All new construction has them and has had for many years now..decades actually. They work ...most of the time! :D Also, if the ground wire going to the bottom of the unit is not a solid connection, the arrestor is no good anymore, a lightning strike has blown the connector off and it needs to be changed out. Regardless if there is a transformer mounted LA or not, you should still have all your expensive electronics on an UPS, as Evan has said.

torker
11-23-2011, 06:17 AM
Ahhh...thankyou very much guys. I'll have a looksee if there is any sort of lightning protection when I go back down there this weekend.
Russ

The Artful Bodger
11-23-2011, 01:18 PM
I havent seen a single wire earth return mains service in New Zealand for many years, maybe I dont get into the back blocks like I used to!


We installed sensitive equipment in many airports around the world and some had quite dodgy power supplies but in every case we installed a combination of battery charger, battery bank and inverter. Of course this is what a UPS is although the ones we installed were a little bigger than what you can buy at the local PC shop.

OwenG
11-23-2011, 02:39 PM
AB, and others, this system is still used in the King Country