House Wiring

[Simon Hickie]

We've just had the surveyor's report for our proposed new house (well built in 1865 actually). He has recommended a rewire, something we were expecting as the sockets etc. seem to date from the 1960s or so.

Naturally I sense an opportunity for the hifi room. Is there anything in particular anybody would recommend with respect to getting the best mains quality? I think the consumer unit is pretty close to the proposed hifi room, so I'm thinking perhaps a dedicated bit not connected to the rest of the ring main if feasible.

[terrybooth]

As I'm sure Richard will say - a spur not a ring main. I did this in a house and used 10mm (cooker) cable (with a suitable circuit breaker) and non-switching outlets. It as obviously difficult to do an AB comparison but I thought it made a difference - but not as much difference as a BMU made to my system.

[Dr Bunsen Honeydew]

Get the whole house wired as fully radial not rings. In your hi-fi room wire to BS546 16 amp not BS1363 13amp. The rest of the house wire to BS1363 as it will be a PITA changing plugs on everything. BUT note by working with radial instead of ring circuits the fuses in the plugs can be removed and replaced with a wire or copper bar as they are not needed anymore (prompt the arrival of snarling know nothing eeediots saying your life will be in danger). Get as high quality a CU (consumer unit) as possible and have the input wired in through a LARGE (4 or 5Kva) isolation transformer, then you will get safety and most of the benefits of the BMU and other benefits on top. Cable not important just good quality.

[Simon Hickie]

Many thanks Doc. Just the sort of advice I was looking for.

[Geoff.R.G]

...the fuses in the plugs can be removed and replaced with a wire or copper bar as they are not needed anymore (prompt the arrival of snarling know nothing eeediots saying your life will be in danger).

There is risk only if said appliances are to be used in another location, such as a hotel or friend's house.

[Dr Bunsen Honeydew]

The risk is so close to zero as to be insignificant. It is only a possible problem with a faulty ring. This below is why you should use radial circuits in new build.

The final ring-circuit concept has been criticised in a number of ways compared to radials, and some of these disadvantages could explain the lack of widespread adoption outside the United Kingdom.

Fault conditions are not apparent when in use.
Ring circuits may continue to operate without the user being aware of any problem if there are certain types of fault condition or installation errors. This gives both robustness against failure and a potential for danger.

Fault condition Observations
Part of the ring missing or disconnected can result in 2.5 mm2 cables running above rated current without this being obvious to the user.
Radials with a broken connection will not function (if L or N broken), or will function with no safety earth connection (if just E broken).
Inadvertent cross connection between two 32 A rings means that the fault current protection reaches 64 A and the required fault disconnection times are violated grossly.

[Classicrock]

Personally I would stick with a ring in any house I would be selling at some stage. Certainly don't use the round pin plugs cause any surveyor will say it needs a rewire and assume it's old wiring. Running radials to every plug in the house is a PITA unless you are doing a complete refurb. BTW if it was rewired in the late 60s the wiring may be mostly fine if done correctly and same as any new wire.

[Dr Bunsen Honeydew]

Not true, rings are done for cheapness and to be able to use thinner cable (less copper). So why does the rest of the world laugh at us for using them. We were radial up to 1950s, it was a stupid bit of history that caused it, we were broke, copper is expensive and we needed it to build exports. A Gov committee (and we know how loony they are) decided to go for rings in 1946, some houses were even wired with aluminium wire rings. 16 amp round pin is fine on a 16 amp radial to the hi-fi room, sockets easily changed if house sold. I did not say for the rest of the house, but if it worries you use Euro Schuko it is nearly as good as BS546. The main problem is BS1363 is simply crap compared with just about ALL other world mains plugs. Square pins bad contact, fuse, awkward shape and mostly badly made.

[Geoff.R.G]

The risk is so close to zero as to be insignificant. It is only a possible problem with a faulty ring.

Agreed, but there will be those who will be upset if they find out, again unlikely.

[kimangelis]

I have a spur run from my CU