1960s/70s wiring - does these automatically mean a rewire?

[Steve2008]

Hi,

I have a rather long question, but to save boring you good people, I'll ask it in easy nibbles

My house was built in about 1969/1970.

The fuse box definately needs replacing and so does the earth electrode (it is a TT system). Although I am capable of doing this myself I am happy to pay a professional due to the part p regulations etc.

I have had one guy look at it and his reaction was "if the fuse box is that old, the whole house needs rewiring". He would only do the whole house or nothing. He claimed that if he touched any part of the system, then he was responsible for the whole system, so all or nothing.

He didn't inspect or test the wiring.

I have replaced all of the switches and plug sockets recently. Whilst doing so I noticed that the wiring is capped under the plaster and the capping seems to run right up to the boxes, which seem the same as modern galvanised boxes. As far as I could tell from a visual inspection the wiring seems in good condition and everything that should be was earthed.
The house had obviously been professionally wired to the standards of the day during construction, wires and boxes onto breeze block walls before plastering, ring mains for sockets, PVC coated wires. The only anomaly is that the wire spec is different from modern specs for the ring mains. Instead of 2.5mm single core flat twin and earth - it uses a multicore flat twin and earth. The total conductor diameter looks bigger than 2.5mm, actually. Anyone familiar with 1970s cable specs?

Anyway - does this vintage of cable automatically mean a rewire?

Was the electrician correct that he can not under the regs just replace part of the system?

I really would like to replace the fuse box and fit a new earth - but would desperately like to avoid a full rewire if at all possible (the house is all nicely decorated the way we want it... chasing plaster off the walls and ripping up floorboards is not... appealing )

Can anyone please help with advice?

Thanks,

Steve

 

[holmslaw]

..

 

[Pensdown]

The fuse box definately needs replacing and so does the earth electrode (it is a TT system). Although I am capable of doing this myself I am happy to pay a professional due to the part p regulations etc.

If your going to replace the consumer unit I would recommend that you aks your supplier if they can convert your supply to TNC-S. If your supply is suitable some suppliers charge a small fee others may not charge at all.

When you get quotes in for the CU change, get a few more opinions on the state of the cabling. A PIR is by far the best way to do that.

Also, make sure your contractor is registered here http://www.competentperson.co.uk/search.asp

 

[ban-all-sheds]

He claimed that if he touched any part of the system, then he was responsible for the whole system, so all or nothing.

He either believes in myths or he's trying to get you to pay for things you might not need.

Either way get someone else.

He didn't inspect or test the wiring.

Then he has no basis for saying it needs replacing.

Anyone familiar with 1970s cable specs?

[code:1]Imperial Actual Nearest metric
size mm² equivalent
1/0.044 0.98 1
3/0.029 1.28 1.5
3/0.036 1.97 1.5 or 2.5
7/0.029 2.98 2.5
7/0.036 4.60 4 or 6
7/0.044 6.87 6 or 10
7/0.052 9.59 10
7/0.064 14.53 16[/code:1]

Anyway - does this vintage of cable automatically mean a rewire?

No.

Was the electrician correct that he can not under the regs just replace part of the system?

No.

Can anyone please help with advice?

Have it properly inspected.

 

[ban-all-sheds]

I can see where your spark is coming from, I would have a similar attitude.

Shrug.

In changing the ccu he could inadvertently damage cables,

How?

he must test (before carrying out any work if he has any sense)

Agreed.

this could also damage the wiring.

How?

the possibilty that the wiring is so severely damaged it is unsafe and has to be switched off.

How?

If it passes the PIR all well and good

Unless it's you or this other guy being asked to replace the CU...

 

[roberta1000]

If your 'guy' has told you that the house needs a rewire because of the age of the fusebox you should find another guy. Unfortunately there are a good many electricians around who will happily quote you for a complete rewire without taking the trouble to properly investigate (but you'll need to pay for that of course). As you have pointed out, a rewire will make a good deal of mess aside from any cost issues. You should get a proper inspection and test of your existing system with a written (signed) report.

Modern pvc cable doesn't normally wear out. It can chafe or course or be nibbled by rodents or suffer other sorts of localised damage but you can't tell that by age alone. Wiring styles and standards of 40 years ago are different to todays but there is no requirement to bring everything up to date just to replace a consumer unit. For what it's worth my own house is around 30 years old and mostly hasn't been rewired (though admittedly there are a few additional final circuits in it now). If you've already replaced sockets and switches you've probably caught more than 90% of any likely defects.

 

[kai]

A common problem with imperial cable installations, is that the earthing to the lighting circuit is often non-existent, or deficient in some other way.

It would be wise to get the electrician to do a detailed inspection of it.

 

[securespark]

Chances are (IMO anyway) that if your house was built after 1968, it has cpc's in the lighting cables and wiring is pvc. The cpc's for the ring final circuits may be 1mm² or imperial equivalent, but that should not be a problem.

But other's advice is good. Invest in a PIR before you go any further.

 

[reggie perrin]

In changing the ccu he could inadvertently damage cables,

How?

So glad you asked that.

Edit: And all the other Qs.

 

[GaryMo]

...and why the reference to a Cooker Control Unit?

 

[reggie perrin]

mega lols as my youngest would say...not text but say.

Txt spk has transmuted into spk spk.

 

[Steve2008]

Thanks very much for all the replies.

A bit of clarification:

The house is wired with 7/0.029 in the ring mains. The lighting circuits are twin and earth, each metal box being earthed (I checked when I changed the light switches as they are brass) and they look like 1mm so I presume are the imperial equivalent. All pvc, under the plaster and capped.

Wiring to the shower has been changed much more recently to 10mm with a seperate 40A mcd in it's own box fitted by me about 6 years ago.

I do not think the original electrician was trying to rip me off - quite the opposite. He didn't want to touch it.

What happened was my wife organised a new kitchen 'For Christmas' (why oh why does it always have to be 'For Christmas'? )

The kitchen company said, quite rightly, that we needed a registered electrician. After kitchen was gutted (just an empty shell) electrician turns up to rewire. He looks at the earth electrode and pointed out it had been concreted over when the drive was redone some years ago. He can't therefore inspect it and the wire going to it is under spec anyway. O.K. says I, good point, I'll pay for a new electrode, no problem. He then says fuse box is too old. (I say fuse box, not C.U. - because it contains old ceramic fuse holders with bits of wire between the terminals...). O.k. I says, another good point, I'll pay for a new C.U. Then he drops the bombshell that he will only rewire the whole house or nothing. He can't do it then because he hasn't the time, it would have to be the following week, ending on Friday 21st December - leaving me for a week with no kitchen and then a building site for Christmas weekend.

I refuse a full rewire and suggest he does the earth and c.u. He refuses. I try to compromise by suggesting he wires the kitchen and Earth and we come to some arrangement to do the c.u. and whatever wiring was required after Christmas. He replied "I have that happen to me before - I'll do the wiring in the kitchen and then you'll cancel the job after Christmas and I'll be responsible for the installation" (or words to that effect).

Bear in mind I have no kitchen at this point....

So, the only compromise I could agree to was that I would wire in the kitchen myself (in breach of part p? - But what else could I do in the circumstances?) and consider this to be a temporary job. He would then quote me for a full rewire including checking/redoing the wiring in the kitchen (it was wired under the units so can be inspected easily) after Christmas.

He then disappears in his van (looking relieved) and I have never heard from him from that day to this and never received any quote.

With the benefit of hindsite, of course, the wiring should have been inspected before the kitchen was gutted, but you know how these things are... 'Special offer' discount for having the job done in December, totally spontanaity from my 'other half' - it all happened very quick and I didn't really get much say in it until it all went pear shaped....

I think there is a right and a wrong time to rewire a house. At the moment it is all beautifully decorated with fitted carpets throughout and doesn't need re-doing for a while. My wife is studying at home for a professional qualification and needs the disruption and subsequent re-decorating job like she needs a hole in the head. So... quite definately the wrong time. Maybe in a year or two - although I really don't believe the house wiring itself is much cause for concern.

The electrician was quite right, though, the earth is buried and the wire to it is under spec and the fuse box is ancient. I really would, for safety, like to get them replaced ASAP.

So, taking the advice I've been given I will be contacting another electrician to see if we can test the installation then hopefully retain the wiring and just replace the earth and cu.

Steve

 

[baldelectrician]

I would suggest a PIR from a registered electrician. I have been in homes where the wiring is 45 years old and other than a bit of bonding and a new consumer unit all is fine.

I have also been in houses where the wiring is 15 years old and it has been DIY'ed so poorly it all it all needs ripped out.

 

[ban-all-sheds]

I do not think the original electrician was trying to rip me off - quite the opposite. He didn't want to touch it.

I'd not be at all surprised to find that, although registered, he wasn't a "real" electrician...

 

[securespark]

You say the earthing conductor to the electrode was undersized: what size is it?