ELECTRITECTS • Castle Tower Reticulation & Submains Earthing Schedule
AS/NZS 3000:2018 Table 5.1 Conductor Sizing & Fault-Loop Verification • Generated for Engineering Design Pack
Cable Sizing Worked Example
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AS/NZS 3000:2018 Table 5.1 & AS/NZS 3008.1.1
Castle Tower Submains Cascade • Worked Example
High-capacity reticulation network fed from dual 1000kVA padmount substations through Main Switchboards MSB-01 & MSB-02 to Residential (ILU) & House Services (MDB-H) towers. Interactive waterfall resolves active feeder sizing, conductor loop impedance, and required earthing conductors.
✓ AS/NZS 3000 Compliance Audit: 44 Feeds Verified (0 Undersized) •
5 Engineering Clarifications Audited: Lifts 6mm² vs 10mm² (Spec Choice), HDB-B1 integral 4C+E earth, MDB-H 185mm² Al verified for Zs impedance match, Substation MEN main earth clarified.
AS/NZS 3000 Rule:
Al Phase: Table 5.1 Col 3 → max(2 sizes up [thermal], ×1.64 [Zs impedance])
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Cu Phase: Table 5.1 Col 2
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400mm² Al: Thermal = 150mm², Zs = 185mm² → Use 185mm² Al (Match)
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Status Language: Green = Match • Amber = Spec Choice • Red = Undersized • Grey = 4C+E Integral
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Primary Substations & Consumers Mains
Technical Note on Parallel Incomers: Consumer mains comprise 4 × 400 mm² Cu conductors per phase (1,600 mm² total). AS/NZS 3000 Table 5.1 Column 2 caps empirical main earthing conductor at 120 mm² Cu for active conductors ≥ 400 mm².
Adiabatic Status: S = I√t / K = 50,000 × √1.0 / 143 ≈ 350 mm² Cu for 1.0s withstand. 120 mm² Cu relies on upstream service protection clearing in ≤ 0.12s (I²t ≤ 2.94 × 10⁸ A²s). (Same sizing basis applies for Randwick 8 × 300/400 mm² incomers).
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Main Switchboard 1 (MSB-01) Reticulation
Building C Tower & House Services Submains (4 Feeds)
✓ All Match
Basement EV Charging Infrastructure (5 Feeds • 95mm² Al)
⚠️ Runs ≥80m Flagged for Appendix B
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Main Switchboard 2 (MSB-02) Reticulation
Building A (Core A) High-Rise Riser, Lifts & ILU Panels (12 Feeds)
MDB-H.A 185mm² Al Match • Lifts Spec Choice
Building B (Core B) High-Rise Riser, Lifts & ILU Panels (11 Feeds)
MDB-H.B 185mm² Al Match • HDB-B1 Integral 4C+E
Core A & B Basement EV Charging Infrastructure (5 Feeds • 95mm² Al)
⚠️ Runs ≥80m Flagged for Appendix B