This has 2 core carrying the load and an earth. this is NOT 3 core
Cables are specified by the Cross Sectional Area (CSA) of their live & neutral conductors. This is measured in mm². Unfortunately a cable of, say, 10mm² is
often loosely referred to as 10mm cable, giving the false impression to people not familar with cable sizes that they just need to measure the width of the cable with a ruler. The table below gives some typical overall cable dimensions for some standard flat T+E cable sizes. Note that cables from different manufacturers will vary slightly from these dimensions.
Judging what cable size you have:
| CSA | Overall Dimensions | Diameter of each Live/ | Number of strands | Approx Measurement across |
|---|---|---|---|---|
| Neutral copper core strand | bundle of strands (‘diameter’) | |||
| 1mm² | 7.8mm x 4.25mm | 1.13mm | 1 (solid core) | |
| 1.5mm² | 8.2mm x 5mm | 1.38mm | 1 (solid core) | |
| 2.5mm² | 10.3mm x 6mm | 1.78mm | 1 (solid core) | |
| 4mm² | 11.9mm x 6.25mm | 0.85mm | 7 | 2.56mm |
| 6mm² | 13.5mm x 7mm | 1.04mm | 7 | 3.13mm |
| 10mm² | 17.1mm x 10mm | 1.35mm | 7 | 4.05mm |
| 16mm² | 19.4mm x 10mm | 1.71mm | 7 | 5.12mm |
This has 3 cores for carrying the load and an earth. mostly used in 2 way lighting circuits and interlinking smoke alarms.
3 core is also often used to power a fan, i.e permanent live, switched live and neutral.