Product Overview

Summary: This Power Distribution Design Safe Operating Procedure sets out a clear, repeatable method for planning and documenting electrical distribution systems that are safe, compliant, and fit for purpose. It helps Australian organisations design low‑ and medium‑voltage distribution in a way that minimises electrical hazards, supports operational reliability, and demonstrates due diligence under WHS and electrical safety legislation.

Power distribution design has a direct and lasting impact on worker safety, asset integrity, and business continuity. Poorly conceived layouts, inadequate fault protection, or undersized equipment can lead to arc flash incidents, electric shock, equipment failure, and extended outages. This Safe Operating Procedure provides a structured, end‑to‑end framework for how power distribution systems are planned, engineered, reviewed, and documented across Australian workplaces – from initial load assessment and network topology decisions through to protection coordination, earthing, labelling, and as‑built documentation.

The SOP translates complex Australian electrical and WHS requirements into a practical design workflow that can be consistently followed by engineering and project teams. It defines mandatory design inputs, verification steps, and safety-in-design controls, ensuring that hazards are identified and managed at the drawing board, not left to be discovered during installation or operation. By implementing this procedure, organisations can reduce design errors, improve interface between engineers and site teams, and create a defensible record that supports compliance with WHS duties, state Electrical Safety Acts, and relevant AS/NZS standards.

This document is particularly valuable for organisations managing multiple facilities, projects, or designers, where design approaches can vary widely. It standardises how calculations, software models, drawings, and technical specifications are produced and checked, while embedding risk assessment, isolation and access considerations, and maintainability into the design process. The result is safer switchboards and distribution networks, reduced rework during construction, and more reliable electrical infrastructure over the asset lifecycle.

Key Benefits

• Ensure power distribution designs are aligned with Australian WHS law, electrical safety legislation, and key AS/NZS standards.
• Reduce the risk of electric shock, arc flash, and equipment failure by embedding safety-in-design controls into every project.
• Standardise the design process across engineers, contractors, and sites, improving quality, consistency, and constructability.
• Streamline design reviews and approvals with clearly defined inputs, deliverables, and verification checkpoints.
• Demonstrate due diligence to regulators, clients, and insurers with robust, traceable design documentation and decision-making records.

Who is this for?

• Electrical Engineers
• Power Systems Engineers
• Electrical Project Managers
• WHS Managers
• Engineering Managers
• Facilities Managers
• Construction Project Managers
• Electrical Contractors and Designers
• Asset and Operations Managers
• Compliance and Risk Managers

Hazards Addressed

• Electric shock from contact with live parts or exposed conductive parts
• Arc flash and arc blast during switching, fault conditions, or equipment failure
• Electrical fires caused by overloads, short circuits, or poor coordination of protection devices
• Overheating and insulation damage due to undersized conductors or inadequate ventilation
• Touch and step potential hazards arising from inadequate earthing and bonding design
• Unintended energisation and back-feed risks due to poorly planned sources and switching arrangements
• Maintenance and access hazards created by poor equipment layout and clearances
• Nuisance tripping and loss of critical loads due to inadequate discrimination and protection settings

Included Sections

• 1.0 Purpose and Scope
• 2.0 Definitions and Abbreviations
• 3.0 Legislative and Standards Framework
• 4.0 Roles, Responsibilities and Competency Requirements
• 5.0 Design Inputs and Project Initiation
• 6.0 Load Assessment and Diversity Calculations
• 7.0 Network Topology, Redundancy and Reliability Criteria
• 8.0 Voltage Levels, Fault Levels and Short-Circuit Studies
• 9.0 Cable Selection, Routing and Thermal Considerations
• 10.0 Switchboard, Switchroom and Distribution Board Design
• 11.0 Earthing, Bonding and Lightning Protection Design
• 12.0 Protection Philosophy and Coordination (Relays, Fuses, Breakers)
• 13.0 Safety-in-Design, WHS Risk Assessment and Hazard Controls
• 14.0 Arc Flash and Electric Shock Risk Mitigation in Design
• 15.0 Integration of Embedded Generation, UPS and Backup Systems
• 16.0 Labelling, Identification and Single-Line Diagrams
• 17.0 Maintainability, Access, Clearances and Working Space
• 18.0 Design Documentation, Drawings and Calculations Requirements
• 19.0 Design Review, Verification and Approval Process
• 20.0 Change Management and Design Revision Control
• 21.0 Handover to Construction, Commissioning and Operations
• 22.0 Recordkeeping, Version Control and Audit Trail
• 23.0 Continuous Improvement and Lessons Learned

Legislation & References

• Work Health and Safety Act 2011 (Cth) and corresponding state and territory WHS Acts
• Work Health and Safety Regulations 2011 and state/territory equivalents
• Electrical Safety Acts and Regulations (state and territory specific, e.g. Electrical Safety Act 2002 (Qld))
• AS/NZS 3000: Electrical installations (the Wiring Rules)
• AS/NZS 3008.1.1: Electrical installations – Selection of cables – Cables for alternating voltages up to and including 0.6/1 kV
• AS/NZS 3010: Electrical installations – Generating sets
• AS/NZS 3439 / AS/NZS 61439: Low-voltage switchgear and controlgear assemblies
• AS 2067: Substations and high voltage installations exceeding 1 kV a.c.
• AS/NZS 7000: Overhead line design – Detailed procedures
• Safe Work Australia – Code of Practice: Managing Electrical Risks in the Workplace
• Safe Work Australia – Code of Practice: Managing the Risk of Falls at Workplaces (for switchroom access and work areas)
• AS/NZS ISO 31000: Risk management – Guidelines