Conductive parts of electrical equipment that can be touched and are not normally live, but may become live under fault conditions (e.g., a motor frame or metal distribution board panel).
SS 551 specifies that the earth resistance of for LV installations unless otherwise justified by calculation. However, for TT systems, a higher resistance (up to 200 ohms) is acceptable if RCDs with appropriate sensitivity (e.g., 30 mA, 100 mA, 300 mA) are used.
, it is tailored to meet local regulatory and technical requirements in Singapore. The primary objective of the code is to ensure the safety of human life, animals, and property by limiting electrical potential during fault conditions. Scope and Exclusions
Permissible under specific conditions but requires careful calculation for corrosion allowance.
The conductor that connects the main earthing terminal of an installation to the earth electrode. ss 551 code of practice for earthing
Earthing systems degrade over time due to soil corrosion and moisture changes. SS 551 mandates regular inspection and testing using the Fall-of-Potential method to verify ongoing compliance. 6. Implementation and Professional Responsibilities
A conductive rod, plate, or conductor buried in the ground to make direct electrical contact with the earth.
Ensure inspection chambers are built to facilitate regular maintenance and testing by LEWs.
: Clause 13 provides new guidance on earthing conductors used for safety during maintenance. Conductive parts of electrical equipment that can be
Earthing provides a stable reference point (zero potential) for the electrical network. This prevents the voltage of the system from drifting dangerously high during normal operations, transient events, or unbalanced load conditions. Dissipation of Lightning and Surge Energies
A conductive rod, plate, strip, or mesh embedded in the soil to establish electrical contact with the earth.
The central hub of the installation's earthing system. It provides a secure, accessible point for testing and links the earthing system to the main incoming power supply neutral. 4. Bonding: Equipotential and Supplementary
is the Singapore Standard "Code of Practice for Earthing," providing critical guidance on the design, installation, and maintenance of earthing systems for land-based electrical installations. It is a modified adoption of the British Standard BS 7430:2011+A1:2015 , tailored to meet local Singaporean regulatory and environmental requirements. Key Purpose and Scope , it is tailored to meet local regulatory
IEEE 80 (for HV substations), BS 7671 (for final circuits), and SS 555 (for lightning protection).
Integration with the local utility's requirements, which take precedence in specific distribution contexts. Corrosion Protection:
Sensitive solid-state electronic components or static-sensitive equipment.