Hi there Groove,
Just a heads up, i'm currently importing power infrastructure for in this area as part of https://wiki.openstreetmap.org/wiki/NGED_Import_Project. The current area i'm working is a box extending roughly from aberdare to the north of cardiff. If i could ask you to avoid that area until i've i've committed to avoid conflicts, thanks. 

Also i would strongly recommend against mapping power cables as individual ways as it will result in a excessive spam of ways, particularly in areas around primary substations where you can have 15+ cables on top of each other. instead you can group them together using the circuits tag and a circuit relation to map the part of the individual lines.

 
