Not all wire is the same. Here is what to look for.
The right cable carries the current safely, survives its environment and keeps voltage drop low.
1. Stranded vs solid
- Stranded is flexible and handles vibration. Use it in vehicles, caravans and boats.
- Solid core is used in fixed building wiring. That's a licensed electrician's job.
2. Common low-voltage cable types
- Automotive single-core: general 12V wiring.
- Twin-core (figure 8 or sheathed): positive and negative together, common for trailer and caravan runs.
- Tinned marine cable: copper coated with tin to resist corrosion. Worth it in damp, salty places.
- Battery cable: heavy flexible cable for batteries, inverters and winches.
3. Size: mm² vs "B&S" and "auto" sizes
Size cable by its copper cross-section in mm². Some auto cable is sold by its outside diameter or a gauge, and the copper inside can be much smaller than the name suggests. Check the copper area. The Wire Gauge Converter helps compare sizes.
4. Insulation
- Check the temperature rating, especially in engine bays.
- Protect cable with conduit or split loom where it could rub.
- Use grommets through metal panels.
5. Quick summary
- Stranded for anything that moves.
- Size by copper area in mm².
- Tinned cable for damp places.
- Protect it from heat and rubbing.
240V AC mains can kill. In Australia, work on household mains wiring must be carried out by a licensed electrician. Low-voltage DC can still deliver very high current, so treat batteries with respect.
