Earthing — Ss 551 Code Of Practice For

The SS 551:2022 Code of Practice for Earthing is the current Singapore Standard governing the design, installation, and maintenance of earthing systems for land-based electrical installations. Key Overview

4. Main Earthing Terminal (MET) and Conductors

The Main Earthing Terminal (MET) is the central hub where all earth conductors meet. ss 551 code of practice for earthing

6.1 Data Centres and IT Equipment

• Separate functional earth (FE) for electronic reference.
• Functional earth must not be confused with protective earth.
• Loop impedance for FE to be kept below 1 Ω to avoid ground potential rise (GPR).

1. Safety (Protection against Electric Shock): Preventing the appearance of dangerous touch voltages on exposed conductive parts (like metal enclosures) during an insulation failure.
2. Protection against Overcurrent: Ensuring fault currents are of sufficient magnitude to operate protective devices (circuit breakers, fuses) quickly to clear the fault.
3. Lightning Protection: Providing a path for lightning discharge currents to earth.

The code aims to protect human life and property by limiting the electrical potential of current-carrying conductors and non-current-carrying metalwork. The SS 551:2022 Code of Practice for Earthing

Conclusion

SS 551 is more than a technical document—it is a lifeline for electrical safety. Proper earthing, as prescribed by this code, prevents electric shock, fire, and equipment damage, and ensures the reliable operation of modern power systems. Whether you are an electrical engineer, contractor, facility manager, or student, understanding SS 551 in detail is not optional; it is a professional responsibility. Separate functional earth (FE) for electronic reference