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.


Would doing this significantly improve the house's safety rating in the
eyes of, say, a house-purchaser's surveyor?

Only if the purchaser is sufficiently clued up. You may find an older CU
etc would be commented on during a survey, but only in as much as the
surveyor might comment that you could get an electrical report if
concerned.

Surveys say get it checked regardless. A buyer that understands RCDs - few do - is one that can do the job themselves if they want.


So if your only reason for the change is to make the house more
saleable, I would not bother. If however you are planning to carry on
living there, then its worth it (IMHO) for other reasons.

Work out the cost & size of risk reduction. Compare with other options. The benefit per pound is far from top of the list.


NT