Future-proofing for future rewiring

[Lobster]

My house is not particularly well specc'ed for electrics; although we do have fairly modern RCD-protected CU and reasonably new wiring, we don't have adequate circuits and it's likely that one day I'll want to sort it out and add a few ring mains when the opportunity permits (eg, when one day that new kitchen comes to the top of the round tuit list...).

Anyway, shortly due to arrive at the top of said list is the redecorating of the hall/stairs/landing (urgh). Now, the CU lives in a low cupboard in the hall, and all the cables running from it are buried in the brick/plaster wall above it, travelling up to the ceiling. Can't see any scope for adding in any new cables without serious wall surgery.

So it occurs me that *now* would be a good time to bury some form of conduit in the wall, separate but adjacent to the existing cables, to enable me to run new cables at some time in the future. It would clearly need to be a pretty large cavity to be worthwhile (I might want to put several ring mains down there, and they'd have to be pulled through which would be awkward). "Large" to me implies fairly deeply buried, to ensure the overlying plaster is rigid enough not to crack.

While I'm mulling this over in my head, I'm just wondering if anyone's tried something similar and have any tips for suitable conduit, methods etc?

Thanks David

[cynic]

Several ring mains? For gods sake why? the whole concept of a ring final circuit is to serve a large number of sockets within a specified area. There is a logical reason to have one for upstairs and one for down with a separate one for the kitchen to cater for the relatively high load in the cooking/washing area. A bit of suitably sized unjointed oval conduit for each pair of twin and earths should be fine. Having a smooth inner it makes it easy to thread cables into it.

[ARWadsworth]

Well I know that Tim Watts installed his house electrics in conduit, I'm sure he'll be along soon with some of his tips.

I doubt you need to be more than 3 to 4 mm from the surface to prevent cracking.

[Tabby]

I take it you've rejected the 1800s aprpoach of bare iron wire on ceramic standoffs, surface mounted to allow the heat to dissipate.

NT

[Andrew Mawson]

surgery.

deeply

crack.

anyone's

methods etc?

Nice bit of 100mm square box conduit (galv or pvc to choice) should see you sorted. Half bury it in the wall, plaster up to it, and incorporate it in your decor

AWEM

[Tim Watts]

Bing! and the shopkeeper appeared, as if by magic ;->

IME I found 20mm oval was OK upto 2.5mm (with slop) and fits into the holes in backboxes.

Not reason the OP can't go to a larger width oval here though which would make larger cables possible and generally easier to thread. I can push off- the-reel 2.5 down 20mm oval from one end over a 2m drop - but for longer lenghths, bigger oval would be wise or it may get hard going.

I've got a couple of bits with 2mm plaster over a couple of places, but that's cutting it fine (lots of PVA and plaster squeezed around and behind the conduit - I'd try and get 4mm over, but that's still not a very deep chase and is quite likely to fit in the depth of plaster available.

[Tim Watts]

Not a silly idea at all. Even box it in like the water pipes. A mini dry- riser :)

[Mike Barnes]

Andrew Mawson :

In a previous house I had the problem of getting quite a lot of wires from the cellar to the first floor. The solution was to go up behind the kitchen base units, then from the worktop up to the ceiling in square- section white plastic fence post. Tucked into the corner, it looked fine.

[TheOldFellow]

You'd need to protect it with an RCD to bring it up to modern specs though. I think a little label "Warning High Tension Electricity", just at the right height for three-year-olds would be advised too.

R.

[damduck-egg]

Thinking about it a lot of 1800s installations would have been private ones with accumulators for when the steam/gas engine driven dynamo was shut down. The voltages of some would be not be too different from ELV systems now and in some respects we have gone full circle with those wire and cable systems with bare conductors suspended across counters,window displays etc not being that dissimilar to the 1800s approach.

G.Harman

G.Harman

[Andy Dingley]

That's what I've just done. I inherited an old pipe run made as a "wooden box conduit" that was no longer needed as the CH pipes ran elsewhere and the upstairs cold feed now ran with them. Cleaning out the old box (and its 20 lbs of lead pipe) gave me space to install a pair of side-by-side galv conduits, one for power and one for data.

[David Robinson]

As others have said, it's unlikely you'll need a _few_ ring mains.

But if you do, and you're going to cram them all into a single conduit for a decent run (couple of metres or more) then you need to de-rate them. Which means using even larger cable.

So better to have a very large conduit, or several smaller bits of conduit - not "just the right sized" single conduit with everything crammed in. IMO!

Cheers, David.

[Andrew Gabriel]

For my TV aerials (and one lighting wire), they're dropped down the disused fireplace flues from the loft.

[Steve Walker]

I'm not sure what the voltages would have been, but I do know that before standardisation, there would have been a.c. and d.c. systems of a whole variety of voltages and safety was not considered an issue, so I wouldn't assume that bare conductors would have been at safe voltages. I've seen a child's trainset that was designed to plug into a mains lighting socket, with the bulb removed and placed into the controller as a dropper resistor - if the train came off the tracks and broke the circuit, the voltage across the rails that the child would be about to put the train back onto whould have rised to mains voltage!!!

SteveW

[damduck-egg]

Don't disagree with that, was just pointing out that in some ways we have gone back to basics. After WW2 my late father did some electrical work for a while,all private gensets as the mains hadn't arrived in the area. In a shed down there is still a box still containing lamps for 50V,100V .200V. All normal size std bayonet. There were 12V and 24V as well but I found uses for them many years ago.

Sounds like the early Hornby pictured on here.

running normally they were designed for about 110V on the track. Ideal for a wicked Uncle to give as a present at Christmas. G.Harman

[george [dicegeorge]]