In an agricultural installation using SWA, which statement is true about protective conductors?

• A. The armour must be used as the protective conductor
• B. Armour is optional and can be used as protection
• C. A core must be provided inside the cable
• D. No protective conductor is required

Answer: (C)

The key idea is that a protective earth path must be provided within the cable itself, not relied on from the armour. In SWA cables, the armour is there to protect the conductors physically, but its continuity can be compromised by joints, movement, corrosion, or damage—especially in agricultural environments. To ensure a reliable and low-impedance path to earth at all times, a dedicated protective earth conductor is included inside the cable cores. This insulated earth core (usually green-yellow) is connected to the metalwork and to the system earth at the point of installation, providing a consistent protective path regardless of the armour condition. So, having a core inside the cable specifically for protection is the correct approach. The armour is not treated as the protective conductor, and no protective conductor would be required only if the system didn't need earthing, which is not the case here.