1976 House Wiring Question

[roblatus]

I am currently in the process of buying a house built in 1976.

I looked at the consumer unit and it is a grey metal box with bakelite circuit breakers in it. There was no sign of any RCD protection.

I am wondering what are the chances of this property having aluminium wiring?

Or is it more likely to have copper at this age?

Don't really want to be re-wiring as i did in my current property.

More than capable of doing it but a back ground in the aerospace electrical field and now in a more R+D role makes me want to avoid another domestic re-wire if at all possible.

It would not be a deal breaker if the house did need doing though.

Many thanks for any advice.

 

[AndyPRK]

Don't think it will have aluminium.

 

[flyingsparks]

It's likely to be PVC cable and could all be ok, but may need some updating with new consumer unit, RCD protection and possibly upgrading bonding conductors. The best thing to do is get an EICR done which will show up any defects. If anything needs doing, get it done now before you move everything in and it will save you a lot of ball ache!

 

[flyingsparks]

I have only ever come across aly cable once, and that was a 10mm feeding a cooker. It's quite rare in a domestic environment to come across it.

 

[flameport]

It will not have aluminium wiring.

The fusebox should be replaced.

The main problem will be the severe lack of socket outlets, as properties in the 1970s typically only had 1 socket in each bedroom and possibly 2 or 3 in the other rooms.

 

[Taylortwocities]

And possibly the lighting circuit(s) will not have an earth, which will stop you having any metal switches or light fittings unless they are special "double insulated" ones.

 

[roblatus]

Thanks for the quick replies chaps. I am more than happy to change the consumer unit and am also more than capable of doing it myself and have already identified RCD protection as a must do job when we get moved in.

Yes there does appear to be a shortage of sockets so will also need to add a few extra but probably no more than half a dozen throughout the house.

There is already at least one metal light fitting but not sure of the presence of an earth in the lighting circuit, however the property has been rented out by the owners for some time so hopefully it will be ok.

Just to add i fully intend on testing the installation for continuity, insulation resistance and earth loop impedence. I did this myself for an extension we had built a few years ago in my current property and was deemed a competent person by the building regs guy from the council and simply filled the appropriate documentation in myself following completion of testing.

 

[EFLImpudence]

Giving of building notice or deposit of plans
6
“(6A) A person intending to carry out building work in relation to which Part P of Schedule 1 imposes a requirement is required to give a building notice or deposit full plans where the work consists of—

(a)the installation of a new circuit;
(b)the replacement of a consumer unit; or
(c)any addition or alteration to existing circuits in a special location.”; and

“special location” means—
(a)within a room containing a bath or shower, the space surrounding a bath tap or shower head, where the space extends—
(i)vertically from the finished floor level to—
(aa)a height of 2.25 metres; or
(bb)the position of the shower head where it is attached to a wall or ceiling at a point higher than 2.25 metres from that level; and
(ii)horizontally—
(aa)where there is a bath tub or shower tray, from the edge of the bath tub or shower tray to a distance of 0.6 metres; or
(bb)where there is no bath tub or shower tray, from the centre point of the shower head where it is attached to the wall or ceiling to a distance of 1.2 metres; or
(b)a room containing a swimming pool or sauna heater.”.

 

[roblatus]

So, if i understand correctly i need to obtain building regs approval for a consumer unit change?


Thanks again.

 

[DaftPunk]

I'd be rewiring any house with 40 year old wiring as a matter of course. Who knows what's been done with it over the years, plus it will not be up to the demands of modern gadgets. As it's a new house now is the time to do it before you think about decorating etc.

 

[securespark]

So, if i understand correctly i need to obtain building regs approval for a consumer unit change?


Thanks again.

Yes.

As FP says, it is highly unlikely to have alu wiring.

Aluminium twin and earth cable was introduced in the early 70's when there was a severe copper shortage. I have seen it a few times in my career. It is a PIA to work with and terminate and can cause high-resistance joints at the drop of a hat.

I have not seen it since the early 90's, but if I came across it today, I would advise the customer it was sub-standard and advise replacement.

In my experience, by the mid-70's, copper was back on the scene, baby.

 

[sparkwright]

I wouldn't expect aluminium wiring in the house. And 'tinned' copper would have become extinct by 1976 too.

I wouldn't expect to have to re-wire a house built in 1976, though that's not to say an inspection and some upgrading won't be necessary.

Look out for an DIY 'improvements' that may have been made.

There may not be a 10 mm green and yellow bonding cable from the fuse box to the water and gas incoming pipes.

The consumer unit could do with being replaced.

Another common problem is where switches and sockets have been replaced by DIYers, the connections can be poorly made.

 

[roblatus]

I wouldn't expect aluminium wiring in the house. And 'tinned' copper would have become extinct by 1976 too.

I wouldn't expect to have to re-wire a house built in 1976, though that's not to say an inspection and some upgrading won't be necessary.

Look out for an DIY 'improvements' that may have been made.

There may not be a 10 mm green and yellow bonding cable from the fuse box to the water and gas incoming pipes.

The consumer unit could do with being replaced.

Another common problem is where switches and sockets have been replaced by DIYers, the connections can be poorly made.

This is also my own view on the situation. As a first step i will be doing some basic testing and inspection of the system myself. contintuity, insulation resistance and visual checks where possible.

Then a consumer unit change, either by myself (after consulting the relevent building reg people) or getting someone in to do it.

Will also require some additional sockets in several rooms, again something i am more than capable of doing.

Should the resistance and insulation tests (and possibly and earth fault test) prove satisfactory along with a visual inspection i also see no reason to carry out a full rewire.

Hope you are all correct on the aluminium wiring issue. fingers crossed. If a full re-wire is required i would be tempted to have a radial in each room with 4mm cable supplying it. This would allow me to re-wire the property a room at a time thus avoiding as much disruption seeing as i am moving from Yorkshire to Wiltshire.

 

[flameport]

If a full re-wire is required i would be tempted to have a radial in each room with 4mm cable supplying it.

4mm is excessive - just put a 20A radial for each room using 2.5mm cable.

 

[roblatus]

If a full re-wire is required i would be tempted to have a radial in each room with 4mm cable supplying it.

4mm is excessive - just put a 20A radial for each room using 2.5mm cable.

Would that be in compliance with 17th edition regulations??