On Monday, 12 October 2020 14:11:12 UTC+1, polygonum_on_google wrote:
On Monday, 12 October 2020 10:13:39 UTC+1, JohnP wrote:
Looking down a hole - as I do - there are some modifications being done to
cables at a nearby substation. Some of the old cables are being extended
with "twisted three" cables rather than the usual three phases in a
circular outer.

Any ideas why?

Saw electricity supply to a new housing estate being laid the other week.
Three lots of "twisted three" in a trench - with plenty of very hefty
sealed junctions. All outer layers were red. Didn't see the actual
covering process but suspect a bit of gravel then some concrete and asphalt.

There are some buried cables near here laid as two sets of three red cables
side by side. There is a buried oil pressurisation tank. Every few years
holes get dug as they look for oil leaks. I was told that these cables run
at 33kV but could be operated at 66kV.

John