Estimate Your Wiring Age

This page will try to assist you in identifying the approximate age of your house wiring. You need to know this because all cable insulation breaks down over time and becomes dangerous. The reason that it is dangerous in laymans terms is because when the insulation finally fails, it will cause a lot of heat before the fuse or trip turns the power off. This heat causes electrical fires.

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Lead sheathed cable

Lead sheathed cable

Cable with a lead Sheath - Between 65 and 85 years old.

This cable was routinely used pre 1948. This cabling is a long way past it's usable life. Added to this is the issue of having a lead-based product in your home, this is not an ideal situation.

Recomendation:

This should be replaced immediately.

Lead sheathed cable

Tough Rubber Sheath (TRS)

Tough Rubber Sheath - Between 40 and 70 years old.

This cable's insulation breaks down and allows arcing between conductors that can cause fires. An insulation resistance test will tell you if the cable needs to be replaced or not. Electrical fires caused by insulation breakdown do not give an indication prior to starting.

Recomendation:

This wiring needs to be tested every one or two years if left in service. The likely hood is that this will fail the test and need to be replaced.

Lead sheathed cable

Lighting without CPC

PVC Lighting withoutout CPC (without earth) - Between 50 and 60 years old..

This cable does not have an earth conductor. this is no longer an acceptable application. Howvere if the wiring passes an insulation resistance test, then the wiring can remain IF the light fittings and accesories that use the wiring are rated as CLASS II. This means they are suitable and safe to be used without an earth.

Recomendation:

This wiring may remain if service if all of the fixtures and fittings are CLASS II. The result of the insulation resistance test will dictate the next test interval.

Lead sheathed cable

Twin and Earth

PVC Black and Red cores - Between 10 and 40 years old.

This is the "standard" cable known as twin and earth, but using colours that predate the harmonisation of colours in 2004, which was implemented in 2006. Following a change in the Law in 2005, this how the authorities know if someone installing electrical wiring has comitted a criminal offence (more details here). The colours of the cables date when the install was done, if they are brown and blue they had to have been installed post 2005.