What is this?
In older UK properties, lighting circuits were often installed without an earth conductor (Circuit Protective Conductor or CPC). While this was acceptable under the regulations at the time, it does not meet current BS 7671 standards. Without an earth, metal light fittings and switches can become live if a fault develops, creating a serious electric shock risk.
Common causes
- Property wired before earth conductors were required on lighting circuits
- Old wiring uses two-core cable without an earth (common pre-1966)
- Earth wire was cut or not connected during a previous installation
- Junction box in the ceiling does not carry the earth through
- New metal light fitting installed on old unearned circuit
Is it dangerous?
Yes, this is dangerous if you have metal light fittings or metal light switches. Without an earth, a fault could make the metal parts live at mains voltage. Plastic (Class II double-insulated) fittings are safer on unearthed circuits because there are no accessible metal parts to become live, but the underlying issue should still be addressed.
Can I fix it myself?
No. Running earth wires requires access to the circuit and must comply with wiring regulations. As a temporary measure, you should only use Class II (double-insulated) light fittings marked with the double square symbol on unearthed circuits. Never install a metal fitting on a circuit with no earth.
When to call an electrician
Call an electrician if you discover there is no earth wire when changing a light fitting, if you want to install metal light fittings or switches, or if your home has old two-core wiring throughout. An electrician can install an earth conductor or advise on appropriate fittings.
What will an electrician do?
Inspect the lighting circuit to confirm the absence of an earth conductor
Run a supplementary earth conductor to the light points that need it
Upgrade junction boxes to include the earth connection
Test the circuit to ensure the earthing is effective
Advise on suitable Class II fittings where running an earth is impractical
Typical cost
£100 – £400
Running an earth to a single light point is at the lower end. Earthing an entire lighting circuit costs more, especially if access is difficult.
