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.

Wanderer said:

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.

Well don't we need managers who can prevent problems like this, not
managers who can't? All we're hearing so far is excuses about how
hard it is to fit relays correctly. Didn't you point out in another
post that low voltage high current tests of these 'protected'
circuits were perfectly feasible? Don't the contractors who put the
system together have to demonstrate to their customers that the
system works as required?

Simple problems like the wrong setting for a protection relay should
be avoidable surely?

--
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Chris Game chrisgame@!yahoo!dotcodotuk
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On Sat, 13 Sep 2003 22:46:15 +0100, Chris Game wrote:

Wanderer said:

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.

Well don't we need managers who can prevent problems like this, not
managers who can't?

You can put in place all the management controls you like. It don't stop
humans screwing up from time to time. Try a dose of real-world life.