On Mon, 22 Jun 2015 15:47:39 +0100, John Rumm
wrote:

On 22/06/2015 11:37, wrote:
On Monday, 22 June 2015 11:05:10 UTC+1, John Rumm wrote:
On 22/06/2015 09:56, Jim x321x wrote:
John Rumm wrote in
:

with the existing setup, and I rarely get any inexplicable
tripping of the circuit breakers. As far as I am aware, the
old fuse boxes (even when fuses contained fuse wire) did
what they were designed to do, with no problems.

They did what they were supposed to - and will still do so.
The main thing your current setup lacks is RCD protection.


Thanks to all for the excellently helpful advice.

If I added an RCD covering the entire house (without replacing
the existing fuse box which is already fitted with MCBs, would
that constitute a change to the wiring and thus require building
control notification?

Firstly you don't want a single RCD covering the whole house -
that is a practice that was common during the 15th edition, but is
deprecated now since it offers no "discrimination" in the event of
a fault (i.e. the fault will take out the supply to the whole
house, not just the circuit causing the problem). So many circuits
on one RCD are also more prone to nuisance tripping in the first
place.

A single RCD is moderately likely to not even work.

True, but the failure rate is not high enough to make that relevant I
would say. (IIRC, 15% of those that have never been tested may fail to
operate when they should - but that sill leaves 75% that will work and
potentially prevent an injury)

I don't see that as a failure rate, just additional work to be done to
rectify the earth leakage faults that may have unknowingly have been
present for decades.

Not that I'm saying a whole house RCD was ever the ideal solution.





--

Graham.

%Profound_observation%