[Closed] Sparkytrackworld - buying a house; signs that a rewire might be needed

While you're looking at the Consumer Unit check out the wire colours on the house side...

Red & Black - old, very old.

Blue & Brown - last thirty years.

It's a crude measure but it will give you some indication of how long since it was last done.

take a plug outlet face off and see if they havent just replaced all the covers to make it look new and shiny....

When you're looking at the consumer unit, there must be a notice fixed on it warning you if there is mixed standards used in the cable colours on the circuits.
That could possibly show that older cabling that you can't see is still there, as opposed to there having been a complete re-wire when the CU went in.

[i]Red & Black - old, very old.

Blue & Brown - last thirty years.[/i]

I assume then that red&black = rewire, blue and brown = [i]probably[/i] okay?

Red and black is less than 30 years old, Part P etc only came in about 20 years ago. Nothing wrong with red and black, as long as you have a modern consumer unit with an RCD, I'd leave it all as is.

NB I'm still adding Red and Black to my house now as I add in extra sockets to bedrooms....

NB I'm still adding Red and Black to my house now as I add in extra sockets to bedrooms....

"that was all here when we moved in, guv"

"that was all here when we moved in, guv"

Exactly 😉

We're off to do a second viewing on a property tomorrow. It's old and we know it's going to need a bit of work (plastering, new bathroom etc) but I'd like to get an idea of whether it might need rewiring, esp. as it's at the top end of our budget and we'd be looking to reflect the coost of any works in any offer we might make.

I'm happy to see if it's got a modern consumer unit, and I can have a look at the switches and sockets to gauge how modern they are, but any other tell-tale signs that indicate a rewire might be needed?

It can also depend on who does the work: If you get a professional electrician to do it (as I would recommend) it can become a slippery slope because as soon as they touch something, they have a duty of care to bring it up to the current standards. So, even if you only think surface bits need replacing, this may have a knock-on effect to the rest of the infrastructure.

A classic one for this is the consumer unit.

Yeah, I get your point, but if the consumer unit is old I'm going to assume it needs a full rewire, and that that will cost about 4k (3 bed, 3 reception room, 1 bat, 1 kitchen house), and adjust any ofer accordingly.

If the consumer unit is new and everything looks new-ish, I'll probably assume it's okay and not really look to get anything taken off for the electrics.

If it's a bit of a mix, I'll go somewhere in the middle, but err on the side of caution.

but if the consumer unit is old I'm going to assume it needs a full rewire

Not really, may just need a new consumer unit...

My Victorian house has red and black wiring (in good nick, probably rewired 25 years ago), but I installed a modern consumer unit and RCDs.

As others have said - it can be a slippery slope, so best to prepare for the worst.
However if there is a new(ish) consumer unit in place that would be a good start.
Look for evidence of Earth bonding - Gas pipe, main water pipe, bathrooms etc.
If the sockets are ancient looking that would get alarm bells ringing in my head.

Electricity doesn't mind what colour cable it is running through, however old installations can be horrific, especially if they've been chopped around by enthusiastic DIYers.
Our place was an absolute horror story when we moved in - bare live wires in the loft - live wires in garage, most sockets/lighting not earthed, and the whole lot running off a tiny little board with 4 ceramic fuse wire carriers.

and the whole lot running off a tiny little board with 4 ceramic fuse wire carriers.

I can beat that, our last (owned) house had [b]one[/b] fuse. For EVERYTHING.

Dont take any notice of cable colours. Red and black can be from 2006, which was the last year it was menat to be used, but some people still had a stock of it, so there is no way of telling the age just by the core colours.
If it is brown and blue cores, it will be after 2004.
Quote:
"If you get a professional electrician to do it (as I would recommend) it can become a slippery slope because as soon as they touch something, they have a duty of care to bring it up to the current standards."

No they don't. Any NEW work must be to current Regulations.
The Earthing and Bonding should also be suitable for continued use. If you get some idiot in, and he sees a 4mm earth cable, he'll say it should be 16mm now. It doesnt, in most situations. Many sparkies are too thick to do a few calculations to see if what is already installed will comply to current regulations. There are 2 ways of determing earth cable sizes, either via a Table in the guidebook which overly errs onto a bigger cable size, or by doing a square root/division/multiplication calculation after doing a simple test. Guess which one most sparkies use?

To answer the OPs question, it takes 15 mins to make an informed decision as to whether a rewire is required. This involves a few checks at accessories, and a few insultaion tests to test the cables integrity.
Basically:
If an old fuse box, with rubber cables, then a rewire is usually recommended.
If an old fuse box with PVC cable then you may get away with a new consumer unit (far safer than a fusebox).
If a new(ish) CU, and PVC cable, then you should be good for many years.

if its not acu with rcd factor in a full rewire.. the most expensive item in the house though is the central heating.. get this fully surveyed by a gas safe engineer. i normally charge 65 for a written report and folks always use it as a negotiating tool..

You can see the original earth bonding wire in my house. A bit pathetic if you ask me....

[url= https://farm6.staticflickr.com/5476/12415057325_c9b46ed1ac_z.jp g" target="_blank">https://farm6.staticflickr.com/5476/12415057325_c9b46ed1ac_z.jp g"/> [/img][/url][url= https://flic.kr/p/jV5q1v ]TN-S Earth Bonding[/url] by [url= https://www.flickr.com/people/75003318@N00/ ]brf[/url], on Flickr

We got told in our survey the house needed rewiring. Not dead yet.

[i]the most expensive item in the house though is the central heating.. get this fully surveyed by a gas safe engineer.[/i]

we've got a tame plumber coming with us on the viewing, the main reason being to look at what I reckon will be a prehistoric boiler.

That looks like a 10mm earth cable.
It will be fine for the vast majority of domestic situations.
The only time it may need upgrading is if you are very close to the local substation/transformer, and you are having electrical work done.
It would need a fault current of 4kA to need a bigger cable. Most domestic properties are in the region of 800 - 2000A