On Wed, 17 Sep 2008 22:58:23 +0100, Tim S wrote:

Perhaps over-reliance on a test tool in the belief it was testing
everything?

Probably or lack of understanding of the test tools limitations. A simple
DC loop tester will check for correct "pairs" and a single or multiple
*different* wiring errors would be detected. However it won't pickup the
*same* wiring error at each end of the cable, that does require far more
sophisticated kit to detect.

--
Cheers
Dave.