In article ,
charles writes:
In article ,
wrote:
On Wednesday, 24 August 2016 15:51:46 UTC+1, David wrote:
Does the fact that an electrician signed off this installation imply
that the rest of the system was safe at the time of the upgrade?

No.

The installation (or minor works) certificate only relates to the new
work stated on it.

The electrician should not have *knowingly* reconnected *unsafe* wiring
to the new consumer unit, but that does not mean the wiring was safe. In
particular there may be defects which were not visible and not apparent
on testing, eg bare live wires under the floorboards but which
nevertheless pass an insulation test. Old rubber wiring can also pass an
insulation test if not disturbed, but can crumble at a gentle touch.

"upgrading the fuses from wire to plug in RCD," doesn't quite make sense
either.

It does if it was a Wylex CU. They were designed with that in mind.

You can swap out a Wylex BS 3036 rewirable fuse for a plug-in *MCB*,
but that's not possible for an *RCD*. You will need to cut a hole in
the cover as the MCB sticks out further.

Note that these plug-in MCB's tend to have a relatively low breaking
current compared with original fit MCBs (and extremely low for the
original push-button ones).

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