scope:

The method described in this International Standard is applicable to any type of cable and group running horizontally, provided that the cables are of equal diameter and emit equal losses. Information is provided on the reduction in permissble current when cables are mounted adjacent to each other. It is limited to the following cases: a) a maximum of nine cables in a square formation, a maximum of six circuits each comprised of three cables mounted in trefoil, with up to three circuits placed side by side or two circuits placed one above the other. Caution is advised where air flow around the cables may be restricted by proximity to neighbouring objects.