1. The Direct Answer: What Is This Cable and What Ampacity Should You Expect?

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.

2. Standard Clarification: Why “Type 2S 6.6kV” Needs Correction on Your BOM

What AS/NZS 1972 Actually Classifies: AS/NZS 1972 is the Australian and New Zealand standard governing cables for underground mining, specifically for fixed and semi-fixed installations (as opposed to AS/NZS 1802 which governs trailing cables for mobile equipment). Within AS/NZS 1972, cable types are classified by their voltage rating, insulation system, screening arrangement, and intended service. “Type 2S” is a specific designation within this classification system. It refers to an elastomer-insulated (EPR), individually screened cable rated for a maximum voltage of 3.3/3.3kV. The “2” indicates the voltage tier (Tier 2, medium voltage up to 3.3kV), and the “S” indicates individual core screening. Type 2S cables are typically used for machine supply circuits, lighting distribution, and auxiliary power within underground coal mines—applications where 3.3kV is the maximum operating voltage.

AS/NZS 1972 是澳大利亚和新西兰的井下矿用电缆标准，专用于固定和半固定安装。在该标准的分类体系中，”Type 2S” 特指额定电压最高为 3.3/3.3kV 的弹性体绝缘（EPR）、带独立屏蔽层的电缆。”2″表示电压等级（中压，最高 3.3kV），”S”表示独立线芯屏蔽。

What 6.6kV Actually Requires: For cables operating at 6.6kV (or, more precisely, 6.35/11kV in the AS/NZS system), the correct classification within AS/NZS 1972 is Mine Feeder Cable—a designation that encompasses heavy-duty, armoured, screened power cables designed for primary distribution circuits in underground mines. Mine Feeder Cables are structurally distinct from Type 2S cables: they feature thicker insulation walls to withstand higher electrical stress, more robust screening (typically copper tape rather than copper wire braid), and mandatory steel wire armour (SWA) for mechanical protection during installation and in-service life. The insulation material is typically XLPE (cross-linked polyethylene) rather than EPR, because XLPE provides superior dielectric performance at higher voltage gradients and allows thinner insulation walls for equivalent voltage withstand.

How This Mismatch Occurs in Practice: BOM descriptions like “Type 2S 6.6kV” typically arise when a procurement team references a previous low-voltage cable order (which was correctly specified as Type 2S at 3.3kV) and applies the same type designation to a higher-voltage cable, or when non-specialist personnel translate a general cable requirement into a BOM line without consulting the AS/NZS 1972 classification system. This is a common and understandable error, particularly on international mining projects where multiple engineering teams contribute to the BOM across different disciplines and geographies. The practical consequence, however, is that a cable manufacturer receiving an RFQ for “Type 2S 6.6kV” faces a contradiction: the type designation specifies one product (3.3kV screened cable) while the voltage specifies another (6.35/11kV feeder cable). Experienced manufacturers will request clarification; less experienced ones may quote the wrong product.

The Correct Specification for Your Application: For a 6.6kV armoured power cable with 3×185mm² conductors intended for primary mine distribution in Kalimantan, the correct AS/NZS 1972 designation is: Mine Feeder Cable, 6.35/11kV, 3×185mm² Cu/XLPE/CTS/SWA/PVC (where CTS = copper tape screen, SWA = steel wire armour, PVC = polyvinyl chloride outer sheath). The voltage rating 6.35/11kV provides insulation redundancy appropriate for tropical environments where humidity and contamination increase the risk of partial discharge. This rating ensures that the cable’s insulation is designed for a phase-to-earth voltage of 6.35kV and a phase-to-phase voltage of 11kV—fully compatible with 6.6kV distribution systems and providing substantial margin for voltage transients.

3. Why 6.35/11kV Rating Instead of 6.6/6.6kV for Kalimantan

The IT Earthing System and Voltage Notation: Australian mining electrical systems typically employ IT (isolated terra) earthing, where the transformer neutral is either ungrounded or grounded through a high-impedance device. In an IT system, a single phase-to-earth fault does not cause an immediate trip; instead, the voltage on the unfaulted phases rises to the full line-to-line voltage relative to earth. This is why AS/NZS standards specify cables where the phase-to-earth rating (Uo) equals the phase-to-phase rating (U)—hence designations like “3.3/3.3kV” and “6.6/6.6kV.” The cable insulation must withstand the full line voltage to earth under single-fault conditions.

Why 6.35/11kV Is the Practical Choice for Kalimantan: For mine feeder cables—which are fixed installations carrying primary power over long distances through hostile environments—engineers routinely specify cables one voltage tier above the system operating voltage. A 6.6kV mining distribution system is best served by cables rated 6.35/11kV for three compelling reasons. First, insulation redundancy: in Kalimantan’s tropical environment, where humidity exceeds ninety percent for months and cable terminations are exposed to condensation, insect ingress, and mineral dust, the additional insulation thickness of an 11kV cable provides a critical safety margin against partial discharge initiation. Second, thermal endurance: thicker insulation at the 11kV rating means the cable can tolerate higher conductor temperatures during overload conditions without insulation degradation—an important consideration when ambient temperatures reach forty degrees. Third, future-proofing: many Indonesian mining operations plan voltage upgrades from 6.6kV to 11kV distribution as mine depth increases and power demand grows; a cable already rated for 11kV avoids premature replacement during voltage migration.

对于矿用馈线电缆——即承载主干电源、穿越恶劣环境的固定安装电缆——工程师通常选择比系统运行电压高一个等级的电缆。6.6kV 矿用配电系统最适合使用 6.35/11kV 额定的电缆，原因有三：绝缘冗余（热带高湿环境的安全裕度）、热耐久性（40°C 环境下过载保护）和未来升级能力（从 6.6kV 升级到 11kV 无需更换电缆）。

4. Complete BOM Specifications: Dimensions, Weights, and Construction

The following specifications describe a mine feeder cable manufactured to AS/NZS 1972 for 6.35/11kV service with 3×185mm² copper conductors, XLPE insulation, copper tape screen, galvanised steel wire armour, and PVC outer sheath. These values are representative of production cables manufactured by Feichun Cable and equivalent AS/NZS-compliant manufacturers. Exact dimensions vary by ±3% depending on manufacturing tolerances and specific compound formulations.

5. Electrical Performance and Short-Circuit Data

Short-Circuit Withstand Significance for Kalimantan Mines: The 26.4 kA one-second short-circuit rating of the 185mm² phase conductor is a critical design parameter. In Kalimantan mining operations, the main feeder cable connects the surface high-voltage switchgear (typically a ring main unit or outdoor switchboard) to underground or pit-bottom distribution substations. The prospective fault level at the cable origin depends on the supply transformer rating and source impedance. For a typical 10/15 MVA, 33/6.6kV mine supply transformer, the prospective fault current at the 6.6kV bus may reach 10–15 kA. The 185mm² conductor’s 26.4 kA one-second rating provides comfortable margin, but the copper tape screen’s 4.2 kA rating must be verified against the actual earth fault current magnitude and protection clearing time. If earth fault current exceeds 4.2 kA or clearing time exceeds one second, the screen cross-section must be increased—a common modification for mines with high fault levels.

6. Ampacity Derating at 40°C: The Core Calculation for Kalimantan

Why 40°C Is the Correct Design Ambient for Kalimantan: Kalimantan—comprising the Indonesian provinces of East Kalimantan (Kaltim), South Kalimantan (Kalsel), West Kalimantan (Kalbar), North Kalimantan (Kaltara), and Central Kalimantan (Kalteng)—experiences tropical equatorial climate with typical daytime air temperatures of 32–36°C. However, cables installed on exposed cable trays in direct sunlight, or inside unventilated cable trenches with metal covers, experience effective ambient temperatures of 40–45°C due to solar radiation gain and restricted airflow. Australian and international cable standards (AS/NZS 3008.1.1, IEC 60287) specify 30°C as the base ambient air temperature for published ampacity tables. Kalimantan conditions therefore require mandatory thermal derating. Using 40°C as the design ambient is conservative but appropriate for reliable continuous operation; cables exposed to direct afternoon sun on steel trays may warrant 45°C design ambient.

Derating Formula and Derivation

The thermal derating factor for elevated ambient temperature is derived from the fundamental heat balance equation governing cable ampacity. The maximum continuous current a cable can carry is limited by the maximum permissible conductor temperature (90°C for XLPE). As ambient temperature increases, the available temperature rise (T_max − T_ambient) decreases, reducing the permissible heat generation and therefore the permissible current. The derating factor is:

For XLPE insulation at 90°C maximum, with actual ambient of 40°C and base ambient of 30°C:

Applying this factor to the base ampacity of 460 A (3×185mm² in free air at 30°C, trefoil touching, per AS/NZS 3008.1.1 Table 22):

在加里曼丹 40°C 环境温度下，3×185mm² XLPE 铠装电缆在电缆桥架上自由空气中的最大安全持续载流量为 420 安培。这是基于 AS/NZS 3008.1.1 和 IEC 60287 的标准降容计算。

7. Direct Burial vs. Cable Tray: Installation-Specific Ampacity in Tropical Soil

Direct Burial in Kalimantan Soil: Many Kalimantan mining operations bury main feeder cables directly in the ground to protect them from vehicle traffic, falling rock, and tropical storms. The ampacity of a directly buried cable depends on soil thermal resistivity (measured in K·m/W) and soil temperature. Kalimantan soils vary significantly: coastal alluvial soils (common in river delta mining areas) are moist and have low thermal resistivity (~0.7–0.9 K·m/W), which is favourable for cable cooling. Inland laterite soils (common in nickel mining areas of Central and Southeast Kalimantan) can be dry and have high thermal resistivity (~1.2–2.0 K·m/W), which severely restricts cable ampacity. The standard reference condition for buried cable ampacity is 20°C soil temperature with 1.0 K·m/W soil thermal resistivity (IEC 60287 / AS/NZS 3008.1.1). Under these conditions, 3×185mm² XLPE/SWA cable carries approximately 400 A.

Buried Cable Derating for Kalimantan Conditions

Kalimantan shallow soil temperature (burial depth 800–1000mm) is typically 28–32°C year-round due to the tropical climate. Using 30°C as the design soil temperature:

This 370 A figure assumes standard soil thermal resistivity of 1.0 K·m/W. In dry laterite soils at 1.5 K·m/W, the ampacity drops further to approximately 310–320 A. In moist alluvial soils at 0.7 K·m/W, the ampacity improves to approximately 400–410 A. Soil thermal resistivity testing—using a thermal needle probe at the actual cable route—is strongly recommended before finalising the cable size for buried installation in Kalimantan. If thermal resistivity testing reveals unfavourable soil conditions, corrective measures include backfilling the cable trench with thermally favourable material (sand-cement mix at ~0.6 K·m/W), increasing burial depth to reach cooler soil layers, or upsizing the cable to the next conductor size (240mm²).

8. Kalimantan Environmental Challenges: Humidity, Termites, UV, and Flooding

Humidity and Condensation: Kalimantan’s relative humidity routinely exceeds ninety percent during the wet season (October–March) and rarely drops below seventy-five percent even during the drier months. This persistent humidity creates condensation risk at cable terminations, junction boxes, and switchgear cable entries—precisely the locations where insulation is most vulnerable. For a 6.35/11kV mine feeder cable, moisture ingress into terminations can initiate water treeing within XLPE insulation, leading to progressive insulation degradation and eventual failure. Cable terminations in Kalimantan should be specified with heat-shrink or cold-shrink technology incorporating moisture-blocking mastic, and termination enclosures should include silica gel breathers or pressurised gas sealing where the mining operation’s maintenance capacity permits. Feichun Cable supplies mine feeder cables with optional water-blocking tape between cores to retard longitudinal water migration if a termination seal is compromised.

Termite Attack on Cable Sheaths: Subterranean termites are endemic throughout Kalimantan and actively attack cable outer sheaths, particularly PVC and polyethylene compounds. Termite damage to directly buried cables is a well-documented failure mode in Southeast Asian mining and infrastructure projects. Standard PVC outer sheaths provide minimal termite resistance. For Kalimantan direct burial applications, Feichun Cable offers two protective measures: first, a nylon over-sheath (polyamide 12) applied over the PVC outer sheath, which provides a physical barrier that termites cannot penetrate; second, PVC compounds incorporating termite-deterrent additives (typically naphthalene-based or pyrethroid-based compounds) that discourage termite feeding. The cost premium for anti-termite protection is approximately five to eight percent above standard cable price—a negligible investment relative to the cost of excavating and replacing a failed buried cable in an operating mine.

Ultraviolet Radiation: Kalimantan sits on the equator, receiving intense UV radiation year-round. Cable trays exposed to direct sunlight subject the cable outer sheath to UV degradation that can embrittle PVC within three to five years, causing surface cracking, chalking, and loss of mechanical integrity. Standard black PVC sheaths incorporate carbon black UV stabilisers that provide reasonable UV resistance (five to eight years at tropical UV intensity). For enhanced UV life, Feichun Cable specifies high-density polyethylene (HDPE) or chlorinated polyethylene (CPE) outer sheaths that resist UV degradation for ten to fifteen years. Where cable trays cannot be shaded, the additional cost of a UV-resistant sheath material is justified by extended cable life.

Flooding and Submersion: Kalimantan’s intense seasonal rainfall (2,500–4,000mm annually) causes frequent flooding of mine access roads, cable trenches, and low-lying cable routes. A directly buried mine feeder cable may be intermittently submerged in standing water for days or weeks during flood events. The cable must withstand this submersion without insulation degradation. XLPE insulation is inherently moisture-resistant and does not absorb water to a degree that affects dielectric performance over the cable’s design life. However, the SWA steel wires will corrode if the galvanised coating is damaged during installation—a common occurrence when cables are pulled through rocky trenches. Feichun Cable applies a bituminous anti-corrosion compound between the inner sheath and armour wires, and between the armour wires and outer sheath, to provide additional corrosion protection in Kalimantan’s wet environment.

加里曼丹环境对电缆提出四大挑战：持续高湿（全年 75–90%+ 相对湿度导致终端凝露和水树枝）、白蚁（侵蚀直埋电缆外护套）、紫外线（赤道强紫外加速 PVC 老化）和洪水（季节性淹没电缆沟槽）。飞春电缆针对每项挑战提供专项保护措施：防水封堵带、防白蚁护套、抗 UV 材料和沥青防腐层。

9. Equipment Compatibility: What This Cable Feeds in Indonesian Mines

A 6.35/11kV 3×185mm² mine feeder cable at 420 A derated capacity in Kalimantan serves as the primary power backbone for a range of mining equipment and infrastructure. Understanding what this cable feeds helps verify that the 185mm² conductor size and 420 A ampacity are appropriate for the specific mine’s electrical load profile.

The equipment compatibility table reveals that a single 3×185mm² mine feeder cable at 420 A (40°C derated) comfortably feeds underground distribution substations, pump stations, ventilation fans, conveyor drives, and workshop facilities. For larger loads such as crusher plants or CHPPs, the 185mm² conductor may be insufficient—two parallel cables or upsizing to 240mm² or 300mm² should be evaluated. This analysis should be performed during detailed mine electrical design, using actual equipment nameplate data and diversity factors rather than the indicative ranges provided here.

10. Total Cost of Ownership in Tropical Mining Environments

Initial Cable Cost: A 6.35/11kV 3×185mm² XLPE/SWA/PVC mine feeder cable manufactured to AS/NZS 1972 specifications costs approximately USD 85–110 per metre, depending on copper price fluctuations, order volume, and specific tropical protection options (anti-termite, enhanced UV, water blocking). A typical mine feeder run of 500–2,000 metres represents a cable cost of USD 42,500–220,000. This is a significant but not dominant component of the total mine electrical infrastructure cost.

Installation Cost in Kalimantan: Cable installation in Kalimantan involves challenges that increase cost relative to temperate-climate installations. Direct burial requires excavation through laterite soils (which can be extremely hard during dry season and unstable during wet season), thermal backfill supply and placement, and reinstatement of the cable route to withstand heavy mining vehicle traffic. Cable tray installation requires fabrication and erection of galvanised cable tray structures rated for tropical wind loads and the cable weight (approximately 12 kg per metre of cable on the tray). Installation labour costs in Kalimantan are moderate by international mining standards (approximately USD 15–25 per metre of installed cable for direct burial, USD 20–35 per metre for tray installation including tray structure), but mobilisation of specialised cable jointing technicians may require importing expertise from Java or Singapore, adding cost and schedule risk.

Failure Cost and Replacement Implications: A feeder cable failure in an operating Kalimantan mine typically causes the following costs: loss of production during the outage (which for a primary feeder cable affects the entire mine or a major production area), emergency fault location and diagnosis (requiring specialised testing equipment that may not be available on site), emergency cable procurement (if spares are not held, lead time for replacement cable delivery to a Kalimantan mine site is typically four to eight weeks including manufacturing and logistics), splicing or complete replacement installation, and re-commissioning and testing. The total cost of a single unplanned feeder cable failure—including production losses—can easily reach USD 200,000–500,000 for a medium-sized coal or nickel mine operating at full production. This reality underscores the importance of specifying the correct cable for Kalimantan conditions (including tropical protection measures) rather than selecting the lowest initial-cost option.

在加里曼丹矿区，一次计划外馈线电缆故障的总成本（包括产量损失）可轻松达到 20 万至 50 万美元。因此，在初始采购时投资正确的热带防护措施（防白蚁、抗紫外、防水封堵）远比选择最低价产品更具经济性。

11. Why Feichun Cable for Your Kalimantan Mining Project

Custom Manufactured for Tropical Mining Markets: Many cable manufacturers produce mine feeder cables designed for temperate climates (Australia, South Africa, Northern Europe) and do not offer tropical-specific modifications as standard options. Feichun Cable specialises in manufacturing AS/NZS-compliant mine feeder cables with built-in tropical protection features—anti-termite sheath compounds, enhanced UV stabilisation, water-blocking tapes, and bituminous armour protection—without treating these as expensive custom additions. Because a significant portion of our production serves Southeast Asian mining markets (Indonesia, Philippines, Papua New Guinea), our manufacturing processes are configured for tropical specifications as a production-line standard rather than a one-off customisation.

Standard Compliance with Custom Printing: One frequently overlooked procurement challenge in Indonesian mining is cable jacket printing. Indonesian mining inspectors (from the Ministry of Energy and Mineral Resources, or ESDM) require specific markings on cable sheaths, including manufacturer identification, standard reference, voltage rating, conductor size, and manufacturing date. AS/NZS 1972-compliant cables must show voltage as “6.35/11kV” (not “6.6kV” or “6/10kV”), conductor size in mm², and the AS/NZS standard number. Feichun Cable applies custom jacket printing to match your project’s exact inspection requirements, including bilingual (English/Bahasa Indonesia) markings where required by local regulation.

Production and Delivery Timeline: Feichun Cable’s standard production lead time for 6.35/11kV 3×185mm² mine feeder cables is ten to fourteen weeks from order confirmation, with delivery to Indonesian ports (Balikpapan, Banjarmasin, Pontianak, Samarinda) via direct shipping from Hefei through Shanghai or Ningbo. For urgent requirements, an accelerated production schedule of eight to ten weeks is available at a modest premium. We maintain strategic inventory of copper rod, XLPE compound, and SWA wire to buffer against raw material supply disruptions that frequently affect cable delivery schedules in the global mining industry.

Technical Support and After-Sales Engineering: Feichun Cable provides comprehensive technical support for Kalimantan mining projects, including ampacity calculations customised for your actual installation conditions (soil thermal resistivity, ambient temperature profile, cable grouping, burial depth), cable sizing verification against your mine’s electrical load profile and fault level study, termination and jointing specifications compatible with your switchgear, and on-site installation supervision by our field engineering team if required. This technical support is included with every mine feeder cable order—not billed separately—because we have found that correct installation and application is the single most important factor in achieving the cable’s design life in tropical mining environments.

12. Procurement Checklist and RFQ Guide

Conclusion: Correct Specification Prevents Costly Procurement Errors

The single most important engineering action you can take for your Kalimantan mine feeder cable procurement is to correct the BOM designation from “Type 2S 6.6kV” to “Mine Feeder Cable, 6.35/11kV.” This correction aligns the specification with AS/NZS 1972’s actual classification system, ensures that cable manufacturers quote the correct product, and prevents inspection rejections on site. With this corrected specification and the ampacity data provided in this guide—420 A at 40°C in free air, 370 A at 30°C direct burial in standard soil—your electrical design team has the quantitative foundation needed to verify that 3×185mm² is the correct conductor size for your mine’s load profile and installation environment.

Kalimantan’s tropical conditions—persistent heat, extreme humidity, termite activity, intense UV radiation, and seasonal flooding—demand cable specifications that go beyond temperate-climate defaults. Specifying the correct tropical protection features at the procurement stage costs five to ten percent more than a standard-specification cable but prevents premature failure modes that could cost fifty to one hundred times more in production losses and emergency replacement. Every dollar invested in correct specification at the procurement stage generates measurable returns in cable reliability over the fifteen to twenty-five year design life of a properly specified, properly installed mine feeder cable.

加里曼丹矿区馈线电缆采购中最重要的工程动作是将 BOM 标识从”Type 2S 6.6kV”纠正为”Mine Feeder Cable, 6.35/11kV”。结合本文提供的载流量数据——40°C 空气中 420A、30°C 直埋 370A——您的电气设计团队拥有了验证 3×185mm² 导体规格的完整技术基础。在采购阶段投入正确的热带防护措施（额外 5-10% 成本）可避免运营中高达 50-100 倍的故障损失。