How old is this cable?

[EAST61]

Had a problem with some flickering lights so I took apart the light switch and the cable was warm to touch. Also a small buzzing noise coming from the switch.

This room will eventually be rewired anyway so happy to leave it disconnected. I've terminated them in wago blocks for now.

Out of interest does anyone know what period this cable is from? It appears to have a grey outer insulation and the copper is "stranded" (not sure if that's the right word)

I also wonder why the MCB or RCD didn't trip.

Would be interesting to know when this room was wired up last.

Thanks!

 

[mwatsonxx]

The cable is from the 1950's

 

[securespark]

Possibly 60's.

It's stranded and tinned.

But it looks like it predates 1966, when regs of that year introduced a cpc (earth wire) to lighting circuits.

There appears to be a green substance on the inside of the metal box which could indicate insulation breakdown and could date the cable to 1965 ish.

Also, the RH red conductor looks like it has discoloured insulation and a tarnished core, indicating a potential loose connection.
If the switch in question was a dimmer, these often buzz to some degree or other. If it was a rocker switch, then that noise could also indicate a loose connection.

As far as rewiring, it will most probably be more than that room that requires rewiring, as the whole circuit is likely to be wired in the same cable.

 

[EAST61]

The cable is from the 1950's

Possibly 60's.

It's stranded and tinned.

But it looks like it predates 1966, when regs of that year introduced a cpc (earth wire) to lighting circuits.

There appears to be a green substance on the inside of the metal box which could indicate insulation breakdown and could date the cable to 1965 ish.

Also, the RH red conductor looks like it has discoloured insulation and a tarnished core, indicating a potential loose connection.
If the switch in question was a dimmer, these often buzz to some degree or other. If it was a rocker switch, then that noise could also indicate a loose connection.

As far as rewiring, it will most probably be more than that room that requires rewiring, as the whole circuit is likely to be wired in the same cable.

Yeah the whole house has been rewired already except for this one room.

There is actually an Earth conductor which you can't see in the picture. It's tight to the top of the backing box. Does that indicate the cable is post-1966?

 

[securespark]

Likely to be somewhere between 1965-1971/2.

I believe cable was made metric in 1970.

 

[EAST61]

Thanks securespark.

And mwatson jog on mate.

 

[bernardgreen]

I also wonder why the MCB or RCD didn't trip.

The MCB would trip if too much current was flowing. A poor contact / loose connection will reduce the amount of current that can flow.
The RCD would trip if there was current flowing to Earth due to a bare wire touching the earthed box

 

[JohnW2]

Likely to be somewhere between 1965-1971/2.

Indeed. Prior to my acquiring my present house (in 1987), it had been rewired in 1970/71, and most of the cable was like that - so it might be at least that late. A fair bit of that cable is still in service.

Kind Regards, John

 

[securespark]

A fair bit of that cable is still in service.

Lots!

And rubber, there's plenty of that still around.

I even saw some lead-covered the other day!

 

[EAST61]

Lots!

And rubber, there's plenty of that still around.

I even saw some lead-covered the other day!

I pulled a lot of old lead insulated cable out of this house after knocking the walls and ceilings down. It had been disconnected and was just sitting there.

I got a small fortune for it at the metal recycling place.

 

[JohnW2]

Lots!

Sorry, I wasn't clear enough - I meant that a fair bit of the 1970/71 imperial (PVC!) cable which I inherited in 1987 is still (in 2017) in service in my house.

.... And rubber, there's plenty of that still around. .... I even saw some lead-covered the other day!

Indeed, there is still plenty of rubber cable, and lead-covered cable, still under my floorboards and buried in my walls (often in places far removed from modern 'safe zones'!) - but, fortunately, all of that was out-of-service, hence 'dead', by the time I moved in!

Kind Regards, John

 

[Iggifer]

Lead sheath cable is brilliant when weighing scrap in. Bury it down the bottom of the pile and ££££

 

[EAST61]

Lead sheath cable is brilliant when weighing scrap in. Bury it down the bottom of the pile and ££££

Just tell them it's lead and get an even better price.

 

[Iggifer]

Just tell them it's lead and get an even better price.

Last time I was there domestic cable was worth more than lead per kg. Otherwise yea, I'd keep it separate

 

[EAST61]

Last time I was there domestic cable was worth more than lead per kg. Otherwise yea, I'd keep it separate

No mate lead is definitely worth more now, at least at my local.