Regardless of whether the armouring of a steel wire armoured cable (swa) is employed as a protective conductor or not, it should always be effectively earthed to ensure the requirements of ADS are met. Where swa cables are connected to metallic enclosures, such as items of switchgear and control gear that also serve as the protective conductor of the circuit concerned, all the requirements of Regulation 543.2.2 (relating to the suitability of a metallic enclosure to provide effective earthing), should be met. Where cables are terminated into enclosures such as consumer units and distribution boards, it should be confirmed that the connection at the interface between the steel enclosure and brass gland, as shown in Fig 1, is mechanically and electrically sound. Many steel enclosures are coated with finishing products, such as epoxy resin or powder coated paint, to protect them from corrosion, but as such coatings are generally non-conductive they are likely to act as a barrier at the interface connection, between the brass gland and the steel enclosure. As a result, the resistance value of the armouring may be increased beyond that acceptable to meet the requirements of ADS. To e...