Protective conductors (PE) must be sized either by:
| Phase conductor cross-section (mm²) | Minimum PE cross-section (mm²) | |--------------------------------------|--------------------------------| | ≤ 16 | Same as phase | | 25 – 35 | 16 | | > 35 | Half of phase conductor (rounded up) |
For PEN conductors, additional cross-section area is required to prevent open-PEN hazards. ss 551 code of practice for earthing
Verification of the earthing system is mandatory before energizing an installation and periodically thereafter.
Key Tests:
SS 551 adopts the IEC classification for earthing arrangements. The standard does not mandate a single type but provides conditions for each.
SS 551 mandates the use of earth electrodes to dissipate fault current into the general mass of the earth. Protective conductors (PE) must be sized either by:
Types of Electrodes:
Requirements:
To eliminate dangerous voltage differences between metallic parts, SS 551 requires bonding.
