· 3 min read
Power cable quotations and drum labels use short letter codes such as 2XY, 2XWY or A2XFY. Each letter describes one layer of the cable, read from the conductor outwards.
The letters
| Letter | Meaning |
|---|---|
| A | Aluminium conductor. No A means copper. |
| 2X | XLPE (cross-linked polyethylene) insulation |
| Y | PVC insulation or PVC sheath, depending on position |
| W | Galvanised steel round-wire armour |
| F | Galvanised steel flat-strip armour |
| Wa / Fa | Aluminium round-wire / flat-strip armour, used on single-core cables |
Worked examples
- 2XY: copper conductor, XLPE insulation, PVC sheath, no armour.
- 2XWY: copper, XLPE insulation, steel round-wire armour, PVC outer sheath.
- A2XFY: aluminium, XLPE insulation, steel strip armour, PVC outer sheath.
- A2XWaY: single-core aluminium, XLPE, aluminium wire armour, PVC sheath.
Why single-core cables use aluminium armour
A single conductor carrying alternating current sets up a magnetic field around it. Steel armour sits in that field and heats up from induced currents. Aluminium is non-magnetic, so it does not. Multicore cables carry currents that largely cancel out, so steel armour is fine there.
Armoured or not?
Choose armoured cable for direct burial, outdoor runs, and anywhere the cable could be crushed or dug into. Unarmoured cable is lighter and cheaper for runs inside trays, trenches and buildings. Our LT power cable page lists every type we make.