AS/NZS 1972 Mine Feeder Cable 6.35/11kV 3×185mm² SWA: Ampacity Derating at 40°C for Kalimantan Coal and Nickel Mines
If you are an electrical engineer reviewing a Bill of Materials for a Kalimantan mining project and the BOM line reads “AS/NZS 1972 Type 2S 6.6kV 3×185mm² Armoured Cable,” the cable you actually need is an AS/NZS 1972 Mine Feeder Cable rated 6.35/11kV, with 3×185mm² copper conductors, XLPE or EPR insulation, copper tape screen, and galvanised steel wire armour (SWA). The “Type 2S” designation on your BOM is technically incorrect for this voltage class—a point we will clarify in detail below—but the intent behind the specification is clear: a heavy-duty, armoured, medium-voltage power cable for primary distribution in an underground or open-pit mine.
如果您是一名审查加里曼丹矿区物料清单（BOM）的电气工程师，BOM 上写着”AS/NZS 1972 Type 2S 6.6kV 3×185mm² 铠装电缆”，您实际需要的是 AS/NZS 1972 矿用馈线电缆，额定 6.35/11kV，3×185mm² 铜导体，XLPE 或 EPR 绝缘，铜带屏蔽，镀锌钢丝铠装（SWA）。BOM 上的”Type 2S”标识在此电压等级下技术上不正确——我们将在下文详细说明——但规格的意图是明确的：用于矿井主干配电的重型铠装中压电力电缆。
The ampacity you should design around at 40°C ambient air temperature in Kalimantan is approximately 420 amperes for cable tray or free-air installation, and approximately 370 amperes for direct burial in tropical soil at 30°C ground temperature. These figures are derated from the standard 30°C base-case ampacity of approximately 460 A (air) and the 20°C base-case of approximately 400 A (ground), using the thermal derating methodology prescribed in AS/NZS 3008.1.1 and IEC 60502-2. The full derivation, including the governing equations and correction factors for Kalimantan’s specific environmental conditions, follows in Sections 6 and 7.
