On 01 Aug 2005 13:19:04 GMT,it is alleged that
(Andrew Gabriel) spake thusly in uk.d-i-y:

[snip]
The sparking would also imply it wasn't a dead short,
as that would produce no continuous sparking.


Indeed, definitely not a dead short, it was a case of the hedgetrimmer
managing to slice through the neutral, not quite through the live, and
thus the blade was live with the (badly burned) neutral touching it
each time it was moved.

I discovered all this later, I somehow didn't have the urge to closely
inspect it while live :-)

[snip]

Something else that I've done is replaced my hedge trimmer
cable with 3-core earthed. The earth is not connected at the
hedge timmer end (like all garden tools, it's double insulated),
but it does make it much more likely the RCD will trip in the
type of fault you had.

Excellent piece of lateral thinking, I may just do this (although
current house has a small enough garden that a 20m cord would be
sufficient, so I will be able to use 1.5mm 3 core).

--
While theoretically and technically television may be feasible,
commercially and financially it is an impossibility.
- Lee DeForest