Why is my consumer unit earth cable corroded green and breaking apart – Advice from Electriman, North London Electricians

Finding a green, flaky or crumbling cable inside your consumer unit is alarming, and rightly so. That green colour is verdigris, which is the result of copper corroding when it is exposed to moisture over a long period. The earth cable is one of the most important conductors in your home, and if it has deteriorated to the point of breaking apart, your electrical installation may not be able to protect you in a fault situation.

What the earth cable does and why it matters

The earth conductor connects metal parts of your electrical system back to the main earthing terminal. If a live wire ever touches something metal it should not, like the casing of an appliance, the earth path carries that fault current away safely and causes a fuse or circuit breaker to trip. Without a reliable earth, that fault current has nowhere safe to go, and the risk of electric shock or fire increases significantly.

How corrosion happens

Copper corrodes green when it reacts with moisture and oxygen over time. Inside a consumer unit this usually happens because of one or more of the following reasons.

1. The consumer unit is positioned on a damp or cold external wall where condensation forms regularly.

2. There is a slow water leak nearby, perhaps from a pipe buried in the wall or a roof void above.

3. The consumer unit enclosure has gaps or poor sealing that allow humid air in.

4. The installation is old and has simply been exposed to ambient mois

Need a qualified electrician in North London?

Electriman covers Mill Hill, Barnet, Finchley, Edgware, Enfield, Watford and surrounding areas. All work is Part P certified and fully insured.