On Thu, 11 Sep 2003 13:06:53 +0100, Chris Game wrote:

robsignals said:

The risk of a second fault on that circuit during this time is
estimated at 1:40,000 though that doesn't apply here with the
system wrongly set-up.

You mean that was the calculated failure probablity ignoring the
protection system?

Some of this seems fairly elementary - I know this is easy to say
with hindsight - but are the electricity supplies really this badly
managed?

No, they're exceptionally well managed, as it happens. What seems to
have happened here is that somewhere along the line, someone either
mis-set a relay or failed to notice that a relay had been mis-set. The
procedure for checking that relay appears to be well-written.