On Wed, 22 Feb 2012 19:40:07 +0000, Graham. wrote:

Reading the Sheriff's report in this case, it seems that the
difference between life and death might be to take an educated
guess
at the breaker re-closure sequence, and in particular, to try to
determine when it has given up retrying.

The one in our feed with a gross fault would have locked out in less
than ten seconds and at most three, possibly only two attempts at
reconnecting. I'm not quite sure what the timing is for intermittent
faults it might be three trips in a minute or three trips in five
minutes before it locks out.

Having been under our pole when an insulator had failed you know when
the power is on by the buzzing noise and smoke...

I would think that the number of people who even know what a
re-closure sequence is will be a very small percentage of the
population.

What you say is indisputable for the general population, but those of
us in uk.diy after reading that report might make the right call if we
were unfortunate enough to be in that position.

Agreed. Even though I knew about re-closures I probably wouldn't have
made the connection should I have wrapped a car around a pole and
brought the lines down.

One poignant thing in that report reminds us that sometimes an
operator makes the decision to attempt to restore the power, and there
is the possibility that he could unwittingly become someone's
executioner.

One reason to keep well clear of fallen lines even if they are dead.
They may become energised and leap about, may only be a second before
the re-closure trips but that is long enough...

Not quite sure what the linesmen do when trying to trace a fault. I
know they repeatedly try to energise the line and I think they move
some form of ground voltage/current detector about between attempts.
There aren't enough switches to open/close to narrow down the section
with the fault.

--
Cheers
Dave.