Finding Voltage information for Power Lines

I recommend not worrying about it - there are plenty of more useful things to map than what voltage a power cable is.

First, remember that you don't have to record the voltage for power lines. You can omit any information from OpenStreetMap that is too difficult/dangerous to collect.

However, if you do want to record the information, you can tell the voltage by the type of pole/pylon used. Search engines is your friend in identifying which is which.

Usually it is true that higher voltages have bigger/higher towers, but concrete sizes and shapes are very country specific and even within one country various types are used for the same voltage (eg. straight, direction change...). I have no idea how they look in UK.
Commonly there are only a few voltages used - this makes it easier to guess in the Czech Republic it is 400V, 22kV, 110kV, 200kV and 400kV. You can look here for some pictures (in czech).
Each power line will have start and end: a power plant, some power station or a transformer. On transformers it is usually written what voltages they transform.
Unfortunately there is no easy universal solution to get the voltage by looking at the poles/wires.

I wouldn't rely absolutely on the following as it is recalled from college a fair while ago!

In the UK the National Grid operates at three voltages: 132Kv, 275Kv and 400Kv. Distribution at higher voltages is more prone to losses and problems caused by corona discharge. To reduce this, the effective diameter of the individual transmission cable is increased. This is achieved by adding more 'wires' to create a bundle conductor. 132Kv is usually distributed using single strand cables. 220Kv use pairs and 400Kv uses quads. This is only relevant on the National Grid using pylon towers and is a guide rather than an absolute truth! (And, yes, I'm aware of some transmission lines using triples - I've no idea when these are used!)

I wouldn't tag using the above info.

try looking at the insulators, the higher the voltage the larger the number of insulators between the tower and the conductor. The insulators are the glass dishes hanging from the tower crossarm points and connecting to the conductor

robin

Hi, roughly estimating you can count 100kV for every meter of insulator. But dont try to climb up and measure it ;-)

But many power lines may hang on older insulators with the ability for more voltage (not the other way round).

To be sure, you should have a deeper look at the lines just outside a sub station. Lines of the same voltage come together at the same part of the sub station, connected by busbars. If a sub station is fed by several voltages, you find a transformer between the parts of that sub station. A 110kV-to-medium-voltage transformer has the size of a garage, while 220/110kV and 380/110kV are quiet larger.

ajoessen