Chapter 2: Definitions

BS 7671 provides a comprehensive list of definitions to ensure clarity and consistency in electrical regulations. This chapter is essential for understanding the terminology used throughout the standard.

Overview of Chapter 2 – Key Definitions

2.1 Electrical Terms

• Live Part: A conductor or conductive part intended to be energized during normal operation.
• Neutral Conductor: A conductor connected to the neutral point of a system and capable of carrying current.
• Protective Conductor: A conductor used for safety purposes, such as earthing or bonding.
• Earth Electrode: A conductive part placed in the ground to provide an electrical connection to earth.

2.2 Protection & Safety

• Residual Current Device (RCD): A device that disconnects a circuit when it detects an imbalance in current flow, preventing electric shock.
• Overcurrent Protection: A system designed to prevent excessive current flow that could damage equipment or cause fire hazards.
• Isolation: The process of disconnecting an electrical circuit to ensure safety during maintenance or inspection.

2.3 Installation & Equipment

• Consumer Unit: A distribution board that houses circuit breakers and RCDs for a building’s electrical system.
• Distribution Board: A panel that distributes electrical power to multiple circuits within an installation.
• Final Circuit: The last section of wiring that directly supplies electrical equipment or outlets.
• Protective Bonding: The connection of metallic parts to prevent dangerous voltage differences.

Why Chapter 2 Matters

• Ensures **consistent interpretation** of electrical regulations.
• Provides **clear definitions** for electricians, engineers, and inspectors.
• Helps prevent **miscommunication and errors** in electrical design and installation.