Steel Wire Armour Cable with 2 cores is primarily used for carrying mains power to applications that don’t require a separate earth. You can use the armour as a separate earth (CPC), however that’s not recommended if the application you’re wiring into requires an earth. For that, you’re better off using 3 Core SWA Cable. 2 Core can also be attached to walls using cable cleats, which allows you to neatly attach the cable to any nearby surface or structure and also helps to keep the cable in place.