No Earth (CPC) on Your Lighting Circuit – What You Need to Know

One issue that sometimes comes up—especially in older homes around Rotherham—is a lighting circuit with no earth (also called no CPC, which stands for circuit protective conductor). 

What does “no CPC” mean? 

It means the lighting circuit doesn’t have an earth wire, which is a key safety feature designed to carry fault current away and prevent electric shock. This was common in houses wired before 1966. 

What can and can’t be installed? 

If there's no CPC on the lighting circuit, metal light switches and metal light fittings (Class 1) CANNOT be installed. These require an earth connection to be safe. 

However, you can still install: 

• Plastic switches 
• Double insulated (Class 2) light fittings, which don’t rely on an earth for safety. 

These are identified by the square-within-a-square symbol on the fitting or packaging. 

What are your options? 

1. Leave the existing wiring in place 

   You’re not legally required to rewire, but we’ll label your consumer unit clearly to show that the lighting circuit has no CPC, and only Class 2 or plastic fittings must be used. This keeps things safe as long as the rules are followed. 

2. Rewire the affected lighting circuit 

   This is the best long-term fix. It brings your home up to modern safety standards, protects your family, and gives you freedom to choose any style of fitting—metal or plastic. It does involve some disruption, but I’ll always talk you through what’s involved and aim to keep mess to a minimum. 

Why this matters 

As a fault-finding and diagnostics electrician in Rotherham, I see the risks of outdated wiring all the time. If we discover a circuit without a CPC during an EICR or light upgrade, I’ll always give you honest advice on the safest next step. 

Need your lights tested or upgraded properly? Want peace of mind that your electrics are safe? Get in touch—I’m here to help.