Major Electrical: MG18 Dewatering System RPEQ Compliance Review
The Challenge
Major Electrical needed independent verification of electrical design documentation for the MG18 dewatering system at a BHP Mitsubishi Alliance operation. The client required a comprehensive RPEQ-certified review of electrical schematics, cable sizing, protection coordination, and compliance with Australian electrical standards to ensure the installation met all regulatory requirements.
Our Approach
Deftec’s electrical engineering team, led by Senior Electrical Engineer Shaun Croton (RPEQ 25178), conducted a detailed compliance review against AS/NZS 3000:2018 and AS/NZS 3008.1.1:2017. We verified current-carrying capacities across all major feeders (including transformer TXF2355, distribution equipment GEA2142, and motor supply circuits CB03/CB04), calculated voltage drop across 270-metre cable runs, and analysed fault loop impedance and protection discrimination. Cable Pro software modelling confirmed that the 150mm2 copper cable installation achieved 413A capacity with 6.63% voltage drop---within the 7% permissible limit for on-site substations. We also validated that circuit breaker discrimination met the 1.5x discrimination requirement, with CB1 (1000A) adequately protecting downstream CB03/CB04 (400A) circuits.
The Outcome
All deliverables were certified compliant, with full RPEQ sign-off provided. The review confirmed the MG18 dewatering system design is safe, compliant, and appropriately rated for operational demands. Major Electrical received a comprehensive technical report supported by detailed cable calculations, time-current coordination curves, and engineering appendices---providing assurance for project stakeholders and regulatory bodies.
Technologies and Capabilities
- Electrical schematic review and compliance analysis
- Cable sizing and current-carrying capacity verification (AS/NZS 3008.1.1:2017)
- Voltage drop and fault loop impedance calculations
- Protection device coordination and discrimination analysis
- MCCB and RCBO protection design
- Low-voltage distribution system design (415VAC)
- RPEQ-certified engineering documentation
- Cable Pro electrical design software