Register your business

Home / Advice / What do the old wiring colours mean?

What do the old wiring colours mean?

Old red and black cable colours were replaced by brown and blue from 31 March 2006 [S4]. Old colours on their own do not mean the wiring is unsafe, but they do tell you it is older.

Last reviewed:

By the QuoteZila editorial team. Editorial policy.

What are the old and new wiring colours?

If you have looked behind a light switch, at the back of a ceiling rose or inside a cupboard under the stairs, you may have seen cables with red and black cores instead of brown and blue.

An Office of the Deputy Prime Minister leaflet, published by Ribble Valley Borough Council, says the colours of the live and neutral wires in electrical cables changed from red and black to brown and blue, the same colours as the wires in flexible leads to portable appliances [S4]. It says cables in the old colours of red and black could be used until 31 March 2006, and that after that all new wiring must be in the new colours [S4].

ConductorColours named in that leaflet
Live and neutral, older cablesRed and black [S4]
Live and neutral, newer cablesBrown and blue, the same as flexible leads to portable appliances [S4]

Colour alone is not a safe way to judge what a wire does. Ask an electrician before anyone works on the installation.

QuoteZila is starting in Cheshire, with Crewe, Nantwich and Sandbach among the first towns, and anyone in the UK can post a job. This page explains what the colours mean so you can talk to an electrician with confidence. It does not tell you how to work on wiring.

What do mixed colours tell you?

Many homes have both. A kitchen refit, a new shower circuit or an extra socket may have been wired in brown and blue, while the rest of the house is still red and black. That is normal and is not a fault on its own.

Where the two schemes meet, the electrician who did the later work should make that clear. NICEIC sells caution labels for alterations or additions to electrical installations where both wiring colours are used [S1]. If you see one, it is a record that the installation has been added to, which is useful to tell any electrician you hire later.

Colours also hint at age. A house that is all red and black has probably not been fully rewired for some time. That is a reason to get it looked at if you have no recent report, not a reason to panic.

What signs matter more than colour?

When an electrician inspects an older installation, the colour of the cores is only one detail. They will be looking for things like:

  • cable sheathing that is brittle, cracked or crumbling
  • very old cable types, such as rubber or fabric covered cables, or cables in lead sheathing
  • an old fuse board with rewirable fuses rather than modern protective devices
  • scorch marks, a burning smell, or sockets and switches that feel warm
  • sockets fitted to skirting boards or wooden back boxes
  • lights that flicker or fuses that blow often

If you see any of these, stop using the affected socket or circuit and ask an electrician to look. Do not open the fuse board, remove covers or try to trace wires yourself.

Electrical Safety First: find a registered electrician; NICEIC; NAPIT. QuoteZila is not affiliated with this organisation.

You can look up a registered electrician through Electrical Safety First, the NICEIC or NAPIT.

When should the wiring be inspected?

An inspection results in an Electrical Installation Condition Report, often called an EICR. It records the condition of the fixed wiring and lists anything that needs attention. Reasons people ask for one include:

  • buying a house, or moving into one with no recent report
  • planning a kitchen, bathroom or extension that will connect to old wiring
  • finding red and black cables during decorating
  • letting a property: GOV.UK guidance says private landlords in England must have the installation inspected and tested at least every five years by a qualified and competent person [S3]

If work is needed, some of it may be notifiable. The Planning Portal says that in England a new or replacement consumer unit and a complete new circuit are notifiable, and that a registered installer can self-certify them [S2].

What should you tell the electrician?

Give the electrician a clear picture before they visit:

  1. The age of the house, if you know it, and any rewiring you know about.
  2. What you have seen. A photo of the fuse board with the cover closed, and of any cable you can see without opening anything.
  3. What you plan. An inspection only, or an inspection before a kitchen, bathroom or extension.
  4. Any symptoms, such as tripping, flickering or warm fittings.
  5. Access. Loft, floorboards and furniture that may need moving.

Ask whether the price is for the inspection only, or includes any small repairs found on the day, and how they will set out the results.

Jobs you might post

These are examples, not taken from real job posts.

  • "Found red and black wires behind a light switch while decorating. Would like the wiring checked before we redo the kitchen."
  • "Buying a terraced house with an old fuse board. Want a condition report before we move in."
  • "Sockets in one bedroom keep tripping. House has a mix of old and new cable colours."

Get quotes from electricians

Describe what you have found and your postcode. Up to five matched local businesses can send you a quote [QZ2]. QuoteZila is free for customers and local businesses [QZ1].

Honest status: QuoteZila is new. We're starting in Cheshire, beginning with Crewe, Nantwich and Sandbach, and growing area by area. Anyone in the UK can still post a job or register a business. How fast you get quotes depends on how many local businesses have joined near you. Businesses can register and receive jobs straight away. We don't check insurance, qualifications or registrations, so please check these yourself before you hire.

Posting a job is not open yet

See our electricians page and the electrician cost guide. For what an inspection involves, see what changes the cost of an EICR.

Questions about old wiring colours

Is red and black wiring dangerous?

Not by itself. The colours tell you the cables are older, not that they have failed. What matters is the condition of the cable, the fuse board and the protection on each circuit. An electrician can inspect the installation and write up what they find in a condition report.

Do I have to rewire because my house has old colours?

No rule says older colours alone mean a rewire. Many homes have a mix of old and new cables after years of small jobs. If you are buying, renovating or worried about the wiring, ask a registered electrician for an inspection and decide from their findings.

Why is there a label about wiring colours on my fuse board?

NICEIC sells caution labels for alterations or additions to electrical installations where both wiring colours are used. If you see one, it usually means newer cables were added to an older installation at some point.

Does replacing an old fuse board need approval?

The Planning Portal says that in England a new or replacement consumer unit is notifiable work, which a registered installer can self-certify. Ask the electrician how the work will be certified and what paperwork you will receive.

Does QuoteZila check the businesses?

No. We don't check insurance, qualifications or registrations, so please check these yourself before you hire. You can report a quote or a business from your job page.

This page is general information, not professional or legal advice. QuoteZila does not check Gas Safe, WaterSafe, NFRC, NICEIC or other registrations against the register on your behalf: look them up yourself.

Related trades

Cost guides

Related pages

Sources

  1. QZ1: QuoteZila product fact. QuoteZila home and jobs-for-tradesmen copy.
  2. QZ2: QuoteZila product fact. QuoteZila FAQ and app README.
  3. S1: Caution labels for changes to the wiring colours, NICEIC. Accessed 2026-10-27. https://shop.niceic.com/products/niceic-approved-contractors-and-domestic-installers-caution-labels-for-changes-to-the-wiring-colours-reg-514-14-1
  4. S2: Electrics: building regulations general information, Planning Portal. Accessed 2026-10-27. https://www.planningportal.co.uk/permission/common-projects/electrics/building-regulations-general-information
  5. S3: Guide for landlords: electrical safety standards in the private rented sector, GOV.UK (MHCLG). Accessed 2026-10-27. https://www.gov.uk/government/publications/electrical-safety-standards-in-the-private-and-social-rented-sectors-guidance/electrical-safety-standards-in-the-private-and-social-rented-sectors-guidance
  6. S4: New rules for electrical safety in the home, Office of the Deputy Prime Minister, via Ribble Valley Borough Council. Accessed 2026-10-27. https://www.ribblevalley.gov.uk/downloads/file/1499/new-rules-for-electrical-safety-in-the-home