What Colour Is the Live Wire?

In a modern UK home, the live wire is brown. The neutral wire is blue, and the earth wire is green and yellow. Electrical Safety First uses those colours for UK plugs and wiring guidance, and it notes that these replaced the older colour system used in many older properties.

For homeowners doing their own electrics, that sounds simple, but we would always add an important warning: colour alone is not enough to identify a conductor safely. Older homes can contain older colour schemes, mixed-age alterations, or previous work that does not match modern expectations. On our own site, we note that older properties may not match modern standards and that this is one of the main reasons we recommend professional testing and inspection instead of relying on wire colour alone.

Modern UK Wire Colours

The answer most people are looking for is straightforward: brown is live in modern UK domestic wiring. Blue is neutral and green/yellow is earth. That is the current colour system homeowners are most likely to see in newer installations, replacement accessories, and recently updated circuits.

That also means that if a homeowner opens an accessory and sees brown, blue, and green/yellow, they are looking at the current UK colour convention. But that still does not make the circuit safe to work on without proper isolation, testing, and competence. Approved Document P covers electrical safety in dwellings, and Planning Portal’s summary makes clear that people carrying out electrical work must be considered competent.

Older House Wiring Can Be Different

In older UK installations, the live wire may be red rather than brown, and the neutral may be black rather than blue. Electrical Safety First says the old colours were red for live, black for neutral, and green for earth, before the changeover to the newer system.

This is where many DIY jobs become risky. A house may have had partial updates over time, so one area may use newer colours while another still uses older wiring. That is especially common in properties that have had extensions, kitchen refits, fuse board changes, or partial rewiring at different points in their history. On our site, we explain that we regularly see a mix of old and updated systems across homes in Wolverhampton, Staffordshire, Shropshire, and the wider West Midlands.

Why Colour Alone Is Not Enough

The biggest mistake a homeowner can make is assuming that the wire colour tells the whole story. Even if the colours look familiar, that does not confirm the circuit has been isolated correctly, terminated correctly, or left in a safe condition by previous work. Part P exists because electrical installation work in dwellings has safety implications, and the government guidance explains that it covers design, installation, inspection, testing, and the provision of information.

That is why, at SM Electrical, we recommend a qualified electrician rather than DIY fault-finding or guesswork. We are NICEIC-registered, fully qualified, and we carry out work to the latest BS 7671 regulations, with certification where required. Our site also highlights that we provide rewiring, fuse board upgrades, socket installations, EICR reports, and wider electrical services for homeowners across the West Midlands.

When a Homeowner Should Call a Professional

If the question is simply “what colour is the live wire?”, the answer is brown in modern UK wiring. But if the real situation is that a homeowner has opened up a socket, light fitting, switch, or junction point and is trying to work out what is what, that is usually the point where we would advise calling a professional. Planning Portal’s summary of Approved Document P says electrical work must be undertaken by someone competent, including being able to check safety circuits.

We would particularly recommend professional help where there are signs of age or electrical problems, such as tripping circuits, burning smells, buzzing sockets, outdated fuse boards, damaged accessories, or uncertainty about the age of the wiring. On our rewiring and fuse board pages, we list those as common signs that a home should be checked, and we explain that older consumer units may not meet current safety rules or provide modern RCD protection.

A Safer Next Step Than DIY Guesswork

For many homeowners, the safest next step is not to keep tracing colours by eye but to arrange a proper inspection. We offer EICR reports for homes and businesses, and on our site we explain that an EICR checks the fuse box, sockets, and wiring and flags risks or outdated circuits.

That is often the right route if a property is older, if the electrics have not been inspected in years, or if there is any doubt about previous alterations. We also carry out rewiring, fuse board upgrades, socket installations, and emergency callouts, so if the issue turns out to be more than a simple query, we can help put it right safely and properly.

Final Thoughts

So, what colour is the live wire? In a modern UK home, it is brown. In older wiring, it may be red. But for homeowners doing their own electrics, the more important point is that wire colour is not a safe substitute for proper testing, competence, and certification.

At SM Electrical, we always recommend using a qualified electrician for domestic electrical work. We are trusted, certified electricians based in Wolverhampton, serving the wider West Midlands, and we carry out domestic electrical work with testing, certification, and safety at the centre of the job.