Can you tell how old household electrics are?

[Madmog]

We had an electrician look at our electrics when we purchased our house 10 years ago, who told us our electrics were about 10-12 years old, making them 20-22 years old now. At the time there was a fuse board and this was replaced by trip switches. We recently had some work carried out by a different electrician who said the properties in our road were re-wired in 1970 and ours hasn't been done since. Is there any way a lay person can get an idea of the age of the electrics, eg colour of wiring, electric meter etc?

 

[1john]

not really. the electric meter is nothing to do with you installation, and could have been changed last week. the wiring colours changed in about 2005 and the only other slight tell tale sign would be the lack of CPC on lighting circuits which happended late 50's and into the 60's. If you got anything older than twin and earth then it could be very old. I would imagine that if the house was wired to a good standard in the sexenties that the installation would be quite servicable and only upgrades would be necissary assuming no one has been in butchering things. things that may not comply could be-

tails not double insulated
Main earth undersized
no main equipotential bonding conductors, or they could be undersized
Consumer unit (fuse box) may need replacing / upgrading
Supplementary bonding (if required) may not be there
Bathroom light may not be cuitable for the zone it is in

Out of interest, why do you need to know

 

[PrenticeBoyofDerry]

It's possible, but sounds like what you have been told is likely to be correct.
As technology moves on, so do materials and installation methods.
so the way it was installed and the equipment used will give you a good idea of when it was installed.

 

[Taylortwocities]

If you download building Regs Part P you will find a handy guide on how installation methods and materials have changed over time.
May be of some help.

Part P the full monty

 

[Paul_C]

the only other slight tell tale sign would be the lack of CPC on lighting circuits which happended late 50's and into the 60's.

The IEE Wiring Regs. didn't require an earth on all lighting circuits until the 14th edition in 1966. However, earths were required before then in certain circumstances, such as for metal light switches, fluorescent lights, metal wall lighting fixtures within reach, etc.

As some other general guides, PVC-sheathed cables started to appear from the mid-1950's, but as you would expect the changeover was gradual and rubber-sheathed were still commonly being installed into the 1960's for general household wiring.

If you have 3-core (or 3-core plus earth) running to 2-way switches, the core colors can be another clue: Red/white/blue cores indicate that the cable dates to the 1963/64 period or earlier, since that's when the colors were changed to red/yellow/blue.

Metric cable started to come into use around 1970, so an installation with all metric-sized cables will be no earlier than that, e.g. ring circuits with metric cable will be solid 2.5 sq. mm conductors which have a bare copper appearance, whereas the older Imperial cable was stranded 7/.029 with tinned copper strands having a silver appearance (however aluminum conductors were used for a short time in the 1960's/70's which will, obviously, appear silver as well).

The recent introduction of "harmonized" European colors for cables about 5 years ago is already well known. Flexes adopted brown, blue & green/yellow around 1970 in place of red, black & green, so any which form part of the fixed wiring (e.g. between a fused spur unit and a fixed appliance) can give another clue.

Bonding and main earthing conductors (to pipework, external earth rod, etc.) are another indicator, assuming the original installation was done to the current IEE Regs. of the time. Prior to 1966 bonding cables were generally black (if not bare); from the 14th edition they became green, then later changed to green/yellow (the exact date escapes me - early 1980's if I recall correctly).

Earths at sockets and light switches (where used) also changed: Up until the mid-1970's they were generally left bare, then the Regs. specified sleeving in green, changed to green/yellow at the same time as the main bonding & earthing made the similar change.

Obviously all of that is a general guide, since there was always something of an overlap period where, for example, metric cable was introduced but homes were still being wired with old stocks of Imperial cable.

 

[ColJack]

some of the electical items such as sockets and CU's etc, have the date on them from the moulding process.. so you can date roughly from those..
not so much the sockets and switches as these can be changed relatively easy, but the CU is a bit harder to change..
it doesn't however preclude the possibility that the CU was changed but not the wiring..

 

[sparkwright]

send some photos of some of the accessories (the fronts and behind if possible).

 

[RF Lighting]

Make / model / BS numbers from the CU and OCPDs is usually a good indicator too.