On Sun, 04 Jun 2006 19:48:01 GMT someone who may be John Anderton
wrote this:-

As others have said, switching off the supply seems like over-kill. I
recently had some builders on the roof, within 10-15 feet of a similar
overhead supply and the electricity board came out and put bright
yellow plastic sheathing on the cable.

People at work need to take reasonable precautions for their own and
other people's safety. The tree people are presumably not trained in
electrical safety, so sleeving the lines is a sensible precaution.
As well as touching the lines directly they may make contact with a
tool or ladder.

Is the tree close enough to the line that the possibility of a
branch striking the line and bringing it down on somebody below is
worth guarding against? If so then that would be a reason for
isolating the line, as per the original posting. Disconnecting the
conductors would only be necessary if they would be struck.

Those trained in electrical safety could approach such a line much
more closely while it is energised and even work on it live. Indeed
it is possible to work on 400,000V lines live, if one knows what one
is doing and has taken the appropriate precautions. However, this is
not something for tree surgeons.

Note for the stupid - don't try this yourself. Being electrocuted is
not a pleasant way to die and it usually takes longer then people
think. At the low voltages of house type wiring it is not a matter
of dying instantly in a shower of sparks as in films.




--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54