at some point our 1963-built bungalow will need a rewire (still has old rubber/steel cables in place). All of the wiring goes into the loft, so no floorboard lifting needed. I changed the CU myself to accomodate a 10Kw shower (cabling for that is new).
Is it a fantasy to believe that I might be able to get the old wires out and new wires in, simply by pulling them through the exisiting voids ? Or should I anticipate having to replaster every room ...
The exisiting wiring for sockets is a ring-main. Light wiring looks like the old type (no earth)..
For a decent jiob EXPECT tpu will have to chase down every wall if solid, and insert new cabling and replaster over the chasing ONLY.
If it is brick or whatever, and not cavity insulated, consider dry lining and insulation and wiring all in one go..
If its stud, you MAY get away with smaller holes, and pulling staff through.
My experience is that its often quicker and cheaper to bite the bullet and be drastic, than spend ages penny pinching and trying to reuse what's there.
WHEN IN DOUBT, RIP IT OUT.
modern machinery makes light of putting an inch groove in masonry. And its not hard even for a crap plasterer like me to make that good afterwards. Paint will be mandatory anyway.
assume none of the old cabling will be in anyway involved or old sockets or lights. Plan the thing from scratch, and do it properly.
Then anything that can be reused as a draw string or back box, is a bonus.
Firstly, when you say "voids", you should be aware that you are not supposed to run cables inside the cavity (other than going directly through both walls).
A house was built in 1963 will likely not have enough socket outlets for modern needs, so presumably, you will be adding quite a few new chases in the wall anyway?
If the original sparkies used steel channelling, then you may be able to pull lightswitch drops in by connecting the new cable to the old. However, you will likely be digging out the old backboxes anyway as they will not have earth terminals.
You are unlikely to be able to pull power cables down old channelling, so you will be re-chasing existing socket outlet positions and probably digging out the old backboxes as well.
Don't forget that if you rewire:
- you will need to add mains-powered and linked smoke alarms
- you will need to ensure your main equipotnetial bonding is up to scratch
- you may need to split one ring final circuit into at least two
- Your lighting circuits may be wired in singles[1], so your cable arrangement for modern loop-in will be somewhat different.
So, all in all, you will be very lucky if you manage to rewire without some plastering/redecoration being required in every room (except perhaps the bathroom).
[1] Where the live wire loops between the switches and the neutral wire loops between the ceiling roses with a single switch wire between switch and rose. This means that the channelling at each light switch position
*may* be too narrow for your purposes.
Depends on the construction. If dry lined you might well be able to pull through cables with minimal making good. If plastered direct to brick it may not be so easy. The cables may or may not be in conduit.
"Part B of the Building Regulations and the Building Regulations Scotland requires all new and refurbished dwellings houses to be provided with a fire detection and alarm system."
"[...] basic requirement can be met by installing interlinked smoke alarms*"
"[...] linked so that operation of one unit will initiate all units"
"be permanently wired from either an independent circuit from the distribution board or from a local regularly used lighting circuit [...]". My paraphrasing.
"have standby power supply, such as battery or capacitor"
*by which, read "smoke and, if appropriate, heat alarms".
On the contrary, it is how lighting circuits used to be wired generally before the advent of earthed lighting circuits and before the use of flat-twin-and-earth loop-in wiring topography.
It is not required, not IME generally used for dwellings, but is permitted if you use single core & earth insulated and sheathed cable to BS6004.
You may get away with it in some cases - if there is conduit in place for light switch drops, these are usually quite easy to pull through. Socket connections can also sometimes be done. However you will find you need far more that originally provisioned, and hence will end up needing to do at least some chases. Sometimes you can spare chasing one room by utilising the reverse side of a wall chased in an adjacent one.
For an early 1950's bungalow I rewired, all the wiring was under galvanised capping, and all of it pulled out very easily (pulling through the new) except for the dining room light switch drop. Fortunately, the dining room and living room had been joined up, meaning that switch wasn't very useful, so I abandoned it rather than wrecking the decorations, and put a double switch at the remaining living room door.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.