In article ,
Matty F writes:
On Aug 10, 8:46 pm, (Andrew Gabriel)
wrote:

inclined to short the live wire to earth and have some kind of
indicator near where we are working to show if the wiring becomes
live. That may not be easy with 600v DC when there's no earth for 6
metres.

Not a good idea for lots of reasons.

What reasons would those be?

Assuming that protective devices will clear a large fault
current in the way you expect, and always safely, is not smart.
For example, you might find that the earth fault loop impedance
is too high (possibly due to electrician working on earthing),
and rather than the fault clearing, all earthed metalwork becomes
live, which is a serious electrocution risk to anyone on the
premises, and a risk of multiple fires starting in obscure places.

In the US, it's not uncommon for lazy electricians to identify
the breaker for a circuit by shorting the circuit out and seeing
which one trips. This technique is responsible for a number
of building fires.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]