# Pylons and Poles (The wooden ones)

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#### acvc

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Arms
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Just a general query about electricity pylons, and the poles that carry supplies down country roads etc. Can anyone give me a general summary of what each cable is for? For example, some wooden poles carry only two cables (horizontally), while others have four cables vertically arranged. Are there any clues as to how many phases, neutrals, earthing (or not in TT areas)? What are these cables then?

And the large steel pylons carrying four or six cables. Are they two sets of three phase, or what?

Alternatively, is there a book that explains all this??????????????????

Thanks

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#### leekemp85

sorry i don't know anything about the pylons but i have always wondered about them the cables, good post hopefully some will answer you

#### acvc

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Arms
OK thanks anyway LeeKemp85. Let's hope someone can enlighten us then. cheers dude.

G

#### gorilla

The big pylons that you see all over carry 2 sets of 3 phase electricity ( 1 set down either side of the pylon with each of the phases having there own sets of cable)

In the country you will get wooden poles that will carry electricity in either

3 phase delta which have 1 cable per phase so 3 cables in total.

or

3 phase star which again have 1 cable per phase but will have an extra cable this is the neutral.

(3 Phase delta doesn't usually have a neutral in the UK.)

Some times you will see a set of poles that only have 2 cables, one of these cables will be a branch from one of the 3 phases and the other will be a branch from a neutral. (Only if connected to a set of three phase in Star)

S

#### Stixicus

As far as i know, where there are 2 overhead lines, the line is only supplying single phase installations. The 4 cables are supplying 3 - phase installations (in countryside areas, may be farms, small rural industrial units, big houses, etc).
The electricity company will only put a single phase lines in if it's only supplying residential properties, if it can get away with it.
The company i work for does some overhead line work, and apparently it's increasingly common that single phase transformers/overhead lines need to be upgraded in the rural areas as more people have been having swimming pools built at their rural pad's which then require a 3 phase supply. Particularly overpaid professional footballers!

T

#### trebor

Just a general query about electricity pylons, and the poles that carry supplies down country roads etc. Can anyone give me a general summary of what each cable is for? For example, some wooden poles carry only two cables (horizontally), while others have four cables vertically arranged. Are there any clues as to how many phases, neutrals, earthing (or not in TT areas)? What are these cables then?

And the large steel pylons carrying four or six cables. Are they two sets of three phase, or what?

Alternatively, is there a book that explains all this??????????????????

Thanks

Hi the pylons are known as transmission and will be carry between 132kv and 400kv in parallel circuits

The wooden poles carry a max of 33kv down to 400V

The hihigh votage wooden poles are 33kv or 11kv the 33kv running between primary substations ( on a ring basis) and the 11kv serving invidual pole transformers around the network which then go on to feed either underground or overhead networks at 400/230V

The 11kv horizontal formation that are are describing can be 3 o2 wire 11kv

The 2 wire will feed a pole transformer which will produce either 2 phases 400V or two phase at 230 V depending on the tapping its run like this purely for cost reasons wher 3 phase is not required from the PT

Hope this helps

#### acvc

##### -
Arms
Thanks leekemp, stixicus, gorilla, trebor. That's cleared things up a bit. Just one more question. The thing that got me wondering about all this, was seeing a wooden pole that had four cables (vertically), but also had a PME sign nailed onto it. Is this an earthing point for a PME supply that's run overground? And ...... does it mean that a house on the same road that has a TT supply could be easily converted to PME?

Thanks people.

T

#### trebor

Thanks leekemp, stixicus, gorilla, trebor. That's cleared things up a bit. Just one more question. The thing that got me wondering about all this, was seeing a wooden pole that had four cables (vertically), but also had a PME sign nailed onto it. Is this an earthing point for a PME supply that's run overground? And ...... does it mean that a house on the same road that has a TT supply could be easily converted to PME?

Thanks people.
The foor conductors run vertically on the low voltage wooden poles are from the top, L1,L2,L3 with neutral at the bottom, the neutral is essentially a PEN conductor, the PME sign on the pole indicates this pole as a multiple earthing point which is every 5th pole hence the name PME, on the underground network all joints are spiked down to create the PME facility

K

#### kung

sometimes in remote areas they will run 2 phases across a field saving cable/money then centre tap 2 phases to get the third ie split phase 460-480v---- 3phase 415v

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