2.5mm Twin & Earth: the cable that wires most South African homes (buyer’s guide)

Open up almost any wall in a South African house and you’ll find the same cable staring back at you: white, flat, with the size stamped on the sheath. Flat twin & earth is the workhorse of SA house wiring — and 2.5mm² is the size most people end up buying. Here’s the plain-English guide to what it is, which size does which job, and how to buy exactly the length you need.

The jargon, decoded

  • Flat twin & earth — one flat white cable containing THREE conductors: a live core, a neutral core, and a bare copper earth wire between them. It’s made for fixed wiring inside walls, ceilings and conduit — not for trailing across the floor to an appliance (that’s a job for cabtyre).
  • mm² — the thickness of the copper inside, not the width of the cable. Thicker copper carries more current. It’s printed on the sheath, so you can always check what’s in your wall.
  • Per metre — exactly what it sounds like. You don’t have to buy a full roll; we cut what you need.
  • Surfix — twin & earth’s round, tougher cousin, used where the cable is surface-mounted or exposed. If your cable runs inside walls and conduit, flat twin & earth is the standard choice.

Which size for which job?

As a rule of thumb in SA homes (your electrician confirms the final sizing against the circuit breaker and SANS 10142-1):

  • 1mm² and 1.5mm² — lighting circuits. Lights draw little current, so the copper can be thinner.
  • 2.5mm² — the workhorse. Plug (socket) circuits in most homes are wired in 2.5mm² twin & earth. Extra plug point, new circuit for the study, repairing a damaged run — this is almost always the size in your hand.
  • 4mm², 6mm² and up — heavy loads and long runs: geysers, stoves, feeds to a garage or cottage sub-board. Bigger appliances and longer distances need thicker copper — we stock flat twin & earth all the way to 16mm².

Not sure? Count what the circuit feeds. Lights only: 1.5mm². Plugs: 2.5mm². Anything with a heating element or its own breaker bigger than 20A: talk to your electrician before you buy.

Why buying the RIGHT size matters

Undersized cable is the dangerous mistake — copper that’s too thin for the load runs hot, and hot cable in a ceiling is how fires start. Oversized cable is merely money wasted. That’s why the size is printed on the sheath and why an electrician will always match cable to breaker: a 2.5mm² plug circuit behind the correct breaker is a system, not a suggestion.

Per metre or 100m roll?

  • Per metre — repairs, one extra plug point, short runs. Measure the route (add a metre or two for slack at each end) and buy exactly that.
  • 100m rolls — rewires, new builds and contractors. If you’re wiring more than a couple of rooms, the roll works out better and you’re not left hunting for a joint.

Trade accounts see their own pricing on both the moment they sign in.

The buying checklist

  • SABS-approved cable only — certified to the SANS standard. All the twin & earth we stock is.
  • Size printed on the sheath matches what your electrician specified.
  • Solid copper conductors — this is not the place for bargain-bin mystery metal.
  • A little extra length — cable routes are never as straight as the tape measure says.

DIY or electrician?

Fixed wiring is electrician territory. Replacing a like-for-like switch is one thing, but running new twin & earth — new circuits, extra plug points, extending a run — must be done (or signed off) by a registered electrician and reflected on your Certificate of Compliance. It’s a quick job for a professional, and it’s what keeps your insurance valid.

Buy it online, cut to the metre

Every size of flat twin & earth — 1mm² to 16mm², per metre or by the roll — is on liteglo.co.za, with real stock and delivery anywhere in SA, or click-and-collect from our counter. Browse the flat twin & earth range at www.liteglo.co.za — and if you’re standing in the aisle of doubt between two sizes, send our team the details of the job; cable questions are what we answer all day.

⚠️ Safety & Compliance Notice

All electrical installations in South Africa must comply with SANS 10142-1 (Wiring Code) and the Occupational Health & Safety Act. Work must be carried out by a qualified, registered electrician. This article is for general educational purposes only. It does not replace professional advice, and Lite-Glo accepts no liability for how this information is used. Always obtain a valid Certificate of Compliance (CoC) for any electrical work.

Need Assistance?

📧 [email protected]
📞 011 781 3100
💬 WhatsApp: 060 322 9674