{"id":8496,"date":"2026-03-06T09:31:05","date_gmt":"2026-03-06T01:31:05","guid":{"rendered":"https:\/\/feichuncables.com\/blog\/?p=8496"},"modified":"2026-03-06T09:35:54","modified_gmt":"2026-03-06T01:35:54","slug":"type-2-vs-type-2s-why-the-s-individual-screen-is-mandatory-for-11kv-underground-coal-mines","status":"publish","type":"post","link":"https:\/\/feichuncables.com\/blog\/type-2-vs-type-2s-why-the-s-individual-screen-is-mandatory-for-11kv-underground-coal-mines\/","title":{"rendered":"Type 2 vs Type 2S: Why the &#8220;S&#8221; (Individual Screen) is Mandatory for 11kV Underground Coal Mines"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">Critical Technical Analysis: Why Type 2S (Individually Screened) Cable is Mandatory for 11kV Underground Coal Mine Power Distribution. AS\/NZS 1972 Compliance, Phase-to-Earth Fault Protection Logic, Arc Energy Prevention, Earth Leakage Relay Integration, Catastrophic Failure Scenarios.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u5173\u952e\u6280\u672f\u5206\u6790\uff1a\u4e3a\u4ec0\u4e48Type 2S(\u5206\u76f8\u5c4f\u853d)\u7535\u7f06\u5bf911kV\u5730\u4e0b\u7164\u77ff\u7535\u529b\u5206\u914d\u662f\u5f3a\u5236\u6027\u7684\u3002AS\/NZS 1972\u5408\u89c4\u6027\u3001\u76f8\u5730\u6545\u969c\u4fdd\u62a4\u903b\u8f91\u3001\u7535\u5f27\u80fd\u91cf\u9632\u6b62\u3001\u63a5\u5730\u6f0f\u7535\u7ee7\u7535\u5668\u96c6\u6210\u3001\u707e\u96be\u6027\u6545\u969c\u573a\u666f\u3002<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img data-dominant-color=\"585046\" data-has-transparency=\"false\" style=\"--dominant-color: #585046;\" loading=\"lazy\" decoding=\"async\" width=\"1072\" height=\"628\" sizes=\"auto, (max-width: 1072px) 100vw, 1072px\" src=\"https:\/\/feichuncables.com\/blog\/wp-content\/uploads\/image-960-1072x628.avif\" alt=\"\" class=\"wp-image-8497 not-transparent\" title=\"\" srcset=\"https:\/\/feichuncables.com\/blog\/wp-content\/uploads\/image-960-1072x628.avif 1072w, https:\/\/feichuncables.com\/blog\/wp-content\/uploads\/image-960-300x176.avif 300w, https:\/\/feichuncables.com\/blog\/wp-content\/uploads\/image-960-768x450.avif 768w, https:\/\/feichuncables.com\/blog\/wp-content\/uploads\/image-960-400x234.avif 400w, https:\/\/feichuncables.com\/blog\/wp-content\/uploads\/image-960-800x469.avif 800w, https:\/\/feichuncables.com\/blog\/wp-content\/uploads\/image-960-832x487.avif 832w, https:\/\/feichuncables.com\/blog\/wp-content\/uploads\/image-960.avif 1101w\" \/><\/figure>\n\n\n\n<!DOCTYPE html>\n<html lang=\"en\">\n<head>\n<meta charset=\"UTF-8\">\n<meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0\">\n<title>Type 2 vs Type 2S: Why the &#8220;S&#8221; (Individual Screen) is Mandatory for 11kV Underground Coal Mines | Feichun Cable<\/title>\n<meta name=\"description\" content=\"Critical technical analysis: Why Type 2S (individually screened) cable is mandatory for 11kV underground coal mine power distribution. AS\/NZS 1972 compliance, phase-to-earth fault protection logic, arc energy prevention, earth leakage relay integration, catastrophic failure scenarios.\">\n<meta name=\"keywords\" content=\"AS\/NZS 1972 Type 2S, Type 2 vs Type 2S cable, AS\/NZS 1972 11kV, individual screen mining cable, individually screened cable, 11kV underground coal mine cable, phase to earth fault protection, mining cable earth leakage, AS\/NZS standard mining cable, Type 2S specifications, 11kV SWA mining cable, steel wire armoured mine cable, XLPE insulated mining cable, collective screen vs individual screen, mining cable safety standards, underground feeder cable, high voltage mining electrical, electrical engineer mining cable, mining cable ampacity, 11kV cross section mm2, AWG mining cable equivalent, mining cable outer diameter, mining cable copper weight, 11kV 3 core weight per km, medium voltage fixed installation mining, coal mine power distribution, mine load centre cable, flame retardant mining cable, 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h3{font-size:.98rem;margin-bottom:.7rem;color:var(--c-body)}.cg{display:grid;grid-template-columns:repeat(auto-fit,minmax(210px,1fr));gap:.75rem}.ci{font-size:.83rem;color:var(--c-secondary);line-height:1.45}.ci .lb{font-weight:600;font-size:.7rem;letter-spacing:.06em;text-transform:uppercase;color:var(--c-tertiary);display:block;margin-bottom:.1rem}.ci a{color:var(--c-link);text-decoration:none}.ci a:hover{text-decoration:underline}.ft{margin-top:2rem;padding-top:1.5rem;border-top:1px solid var(--b-light);font-size:.75rem;color:var(--c-tertiary);text-align:center;line-height:1.55}@media(max-width:600px){.page-wrap{padding:1.2rem 1rem 3rem}.hdr h1{font-size:1.35rem}.tw{font-size:.8rem}.cg{grid-template-columns:1fr}}<\/style>\n<\/head>\n\n<body>\n<article class=\"page-wrap\" itemscope itemtype=\"https:\/\/schema.org\/TechArticle\">\n\n  <header class=\"hdr\">\n    <span class=\"badge\">Feichun Special Cable \u2014 Technical Blog<\/span>\n    <h1 itemprop=\"headline\">Type 2 vs Type 2S: Why the &#8220;S&#8221; (Individual Screen) is Mandatory for 11kV Underground Coal Mines<\/h1>\n    <p class=\"sub\">Critical Technical Analysis: Why Type 2S (Individually Screened) Cable is Mandatory for 11kV Underground Coal Mine Power Distribution. AS\/NZS 1972 Compliance, Phase-to-Earth Fault Protection Logic, Arc Energy Prevention, Earth Leakage Relay Integration, Catastrophic Failure Scenarios.<\/p>\n    <p class=\"sub-cn\">\u5173\u952e\u6280\u672f\u5206\u6790\uff1a\u4e3a\u4ec0\u4e48Type 2S(\u5206\u76f8\u5c4f\u853d)\u7535\u7f06\u5bf911kV\u5730\u4e0b\u7164\u77ff\u7535\u529b\u5206\u914d\u662f\u5f3a\u5236\u6027\u7684\u3002AS\/NZS 1972\u5408\u89c4\u6027\u3001\u76f8\u5730\u6545\u969c\u4fdd\u62a4\u903b\u8f91\u3001\u7535\u5f27\u80fd\u91cf\u9632\u6b62\u3001\u63a5\u5730\u6f0f\u7535\u7ee7\u7535\u5668\u96c6\u6210\u3001\u707e\u96be\u6027\u6545\u969c\u573a\u666f\u3002<\/p>\n    <div class=\"meta\">\n      <span itemprop=\"author\" itemscope itemtype=\"https:\/\/schema.org\/Organization\"><span itemprop=\"name\">Anhui Feichun Special Cable Co., Ltd.<\/span><\/span>\n      <span>|<\/span>\n      <time itemprop=\"datePublished\" datetime=\"2026-03-05\">Mar 05, 2026<\/time>\n      <span>|<\/span>\n      <span>Reading time: ~28 min<\/span>\n    <\/div>\n  <\/header>\n\n  <nav class=\"toc\" aria-label=\"Table of Contents\">\n    <div class=\"toc-label\">Contents<\/div>\n    <ol>\n      <li><a href=\"#s1\">Type 2 vs Type 2S: The Critical Difference That Prevents Explosions<\/a><\/li>\n      <li><a href=\"#s2\">Understanding Cable Screen Architecture: Collective vs Individual<\/a><\/li>\n      <li><a href=\"#s3\">Type 2 (Non-Individually Screened): The Fatal Hazard<\/a><\/li>\n      <li><a href=\"#s4\">Type 2S (Individually Screened): The Safety-Critical Design<\/a><\/li>\n      <li><a href=\"#s5\">Fault Control Logic: Phase-to-Phase vs Phase-to-Earth<\/a><\/li>\n      <li><a href=\"#s6\">Arc Energy Analysis: Why Phase-to-Phase Faults Ignite Methane<\/a><\/li>\n      <li><a href=\"#s7\">Earth Leakage Relay Integration: How Type 2S Stops Explosions<\/a><\/li>\n      <li><a href=\"#s8\">AS\/NZS 1972 Specification: Mandatory Type 2S for 11kV Systems<\/a><\/li>\n      <li><a href=\"#s9\">Complete Technical Specification: Type 2S 6.35\/11kV Cable<\/a><\/li>\n      <li><a href=\"#s10\">Mechanical and Environmental Requirements<\/a><\/li>\n      <li><a href=\"#s11\">Real-World Failure Scenarios: What Happens Without Type 2S<\/a><\/li>\n      <li><a href=\"#s12\">Conclusion: Type 2S is Non-Negotiable for Underground Coal Mining<\/a><\/li>\n    <\/ol>\n  <\/nav>\n\n  <div class=\"body\" itemprop=\"articleBody\">\n\n    <h2 id=\"s1\">1. Type 2 vs Type 2S: The Critical Difference That Prevents Explosions<\/h2>\n\n    <p><strong>The Single Most Important Cable Design Decision in Underground Coal Mining:<\/strong> Whether the cable employs collective screening (Type 2) or individual phase screening (Type 2S). This single engineering choice directly determines whether a mechanical cable failure will result in a phase-to-earth fault (detected and stopped in milliseconds) or a phase-to-phase fault with thousands of amperes of arc current (igniting methane explosions).<\/p>\n\n    <p class=\"cn\"><strong>\u5730\u4e0b\u7164\u77ff\u6700\u5173\u952e\u7684\u5355\u4e00\u7535\u7f06\u8bbe\u8ba1\u51b3\u5b9a\uff1a<\/strong>\u7535\u7f06\u662f\u91c7\u7528\u96c6\u4f53\u5c4f\u853d(Type 2)\u8fd8\u662f\u5206\u76f8\u5c4f\u853d(Type 2S)\u3002\u8fd9\u4e00\u9879\u5de5\u7a0b\u9009\u62e9\u76f4\u63a5\u51b3\u5b9a\u4e86\u673a\u68b0\u7535\u7f06\u6545\u969c\u662f\u4f1a\u5bfc\u81f4\u76f8\u5730\u6545\u969c(\u5728\u6beb\u79d2\u5185\u68c0\u6d4b\u5e76\u5236\u6b62)\u8fd8\u662f\u76f8\u95f4\u77ed\u8def\uff0c\u4f34\u968f\u6570\u5343\u5b89\u57f9\u7684\u7535\u5f27\u7535\u6d41(\u70b9\u71c3\u74e6\u65af\u7206\u70b8)\u3002<\/p>\n\n    <p><strong>The Stakes:<\/strong> Type 2 cables have caused catastrophic explosions in coal mines worldwide. Type 2S cables, paired with earth leakage relay protection, have prevented explosions for decades. Australian law (AS\/NZS 1972) mandates Type 2S for 11kV underground systems. The difference is literally a matter of life and death.<\/p>\n\n    <h2 id=\"s2\">2. Understanding Cable Screen Architecture: Collective vs Individual<\/h2>\n\n    <p>To understand why Type 2S is mandatory, we must first understand the physical difference in cable construction.<\/p>\n\n    <p><strong>Type 2 Architecture (Collective Screening):<\/strong> Three insulated power conductors are bundled together with earth core(s) in the center. The entire bundle is surrounded by a single metallic shield (usually copper tape or braid) and then armoured with galvanized steel wire (SWA). All three phase conductors are electromagnetically protected by this single common shield.<\/p>\n\n    <p><strong>Type 2S Architecture (Individual Screening):<\/strong> Each of the three power conductors has its own dedicated metallic screen (copper tape or braid) applied directly over the conductor&#8217;s insulation. Each individual phase screen is then grounded (connected to earth). The three individually-screened phase conductors are then bundled together and collectively armoured with galvanized steel wire (SWA).<\/p>\n\n    <p><strong>Consequence of This Design Difference:<\/strong> In Type 2, all three phases are electromagnetically coupled through a single field. In Type 2S, each phase has its own isolated electromagnetic field managed by its individual screen, completely decoupling the phases electrically.<\/p>\n\n    <h2 id=\"s3\">3. Type 2 (Non-Individually Screened): The Fatal Hazard<\/h2>\n\n    <p><strong>Mechanical Failure Scenario:<\/strong> A mine rockfall or heavy equipment impact damages a Type 2 cable. The external SWA armor is breached. The mechanical impact crushes the cable, causing insulation of two adjacent phase conductors (say Phase A and Phase B) to puncture simultaneously or near-simultaneously.<\/p>\n\n    <p><strong>Electrical Consequence\u2014Phase-to-Phase Short Circuit:<\/strong> With only collective screening protection, the two damaged phases are now directly shorted together. The fault impedance is extremely low\u2014just the resistance of the conductor cross-section (microscopically small). The fault current magnitude is determined by the total system impedance and can be calculated:<\/p>\n\n    <div class=\"eq\">I_fault = V_line \/ Z_system\nFor 11kV system with typical 10-20 kA SCC: I_fault \u2248 8,000\u201315,000 A per phase<\/div>\n\n    <p><strong>Energy Release\u2014Arc Formation:<\/strong> This enormous current creates an electrical arc between the two phase conductors. The arc temperature reaches thousands of degrees Celsius (comparable to the surface of the sun). The cable insulation and sheath are immediately ignited. The arc energy burns through the cable jacket, exposing the copper conductors to the mine atmosphere.<\/p>\n\n    <p><strong>Explosion Trigger:<\/strong> In a coal mine atmosphere containing methane (CH\u2084) and coal dust, an arc temperature of 1000\u00b0C+ is more than sufficient to ignite both gases. A methane-air mixture ignites at 595\u00b0C. Coal dust ignites at approximately 600\u00b0C. The arc immediately ignites the surrounding atmosphere, causing gas explosion with pressure waves exceeding the structural integrity of underground mine workings.<\/p>\n\n    <h2 id=\"s4\">4. Type 2S (Individually Screened): The Safety-Critical Design<\/h2>\n\n    <p><strong>Same Mechanical Failure Scenario with Type 2S:<\/strong> The same rockfall or equipment impact damages a Type 2S cable. The external SWA armor is breached. The mechanical impact crushes the cable.<\/p>\n\n    <p><strong>Electrical Consequence\u2014Phase-to-Earth Fault (NOT Phase-to-Phase):<\/strong> Because Phase A has its own individual copper screen connected to earth, the mechanical damage to Phase A insulation is immediately shorted to the individual screen (and then to earth) BEFORE any other phase conductor can be contacted. The fault becomes a phase-to-earth fault (single phase to ground), not a phase-to-phase fault.<\/p>\n\n    <p><strong>Fault Current Magnitude Control:<\/strong> The fault current is now limited not by the system impedance, but by the neutral earthing resistor (NER) at the transformer. In Australian coal mines, this is typically set to 5A, 10A, or 50A depending on system design. This is a 100\u20131000\u00d7 reduction in fault current compared to phase-to-phase fault:<\/p>\n\n    <div class=\"eq\">I_fault = V_phase \/ R_neutral (e.g., 6,350V \/ 1,270\u03a9 = 5A typical)<\/div>\n\n    <p><strong>Arc Energy Reduction:<\/strong> The fault current of 5A cannot sustain a high-temperature arc. The arc energy is microscopic compared to the 10,000+ A phase-to-phase fault. No ignition source is created. The cable may be damaged but no explosion is triggered.<\/p>\n\n    <p><strong>Rapid Fault Detection:<\/strong> The earth leakage relay at the substation detects this phase-to-earth fault within 50\u2013100 milliseconds and opens the main contactor, removing power from the cable. The fault is cleared before any meaningful energy release occurs.<\/p>\n\n    <h2 id=\"s5\">5. Fault Control Logic: Phase-to-Phase vs Phase-to-Earth<\/h2>\n\n    <p>This is the fundamental engineering principle that makes Type 2S mandatory for underground coal mining.<\/p>\n\n    <p><strong>Phase-to-Phase Fault Logic (Type 2 risk):<\/strong> Large fault current \u2192 High arc energy \u2192 Insulation ignition \u2192 Atmospheric ignition (explosion).<\/p>\n\n    <p><strong>Phase-to-Earth Fault Logic (Type 2S design):<\/strong> Controlled fault current (via NER) \u2192 Low arc energy \u2192 No ignition \u2192 Rapid protective relay clearing \u2192 Safety maintained.<\/p>\n\n    <p><strong>The Safety Principle:<\/strong> By forcing all mechanical faults to convert to phase-to-earth (not phase-to-phase), the Type 2S cable architecture guarantees that fault energy is insufficient to create ignition sources in explosive atmospheres. This is not a passive feature\u2014it is an active design decision that eliminates the explosion hazard entirely.<\/p>\n\n    <h2 id=\"s6\">6. Arc Energy Analysis: Why Phase-to-Phase Faults Ignite Methane<\/h2>\n\n    <p>To understand the explosion risk quantitatively:<\/p>\n\n    <p><strong>Phase-to-Phase Arc Energy (Type 2 worst case):<\/strong> With 15,000 A fault current and a fault duration of 100 milliseconds (time for main protection to clear), the arc energy is approximately:<\/p>\n\n    <div class=\"eq\">E = I\u00b2 \u00d7 R \u00d7 t \u2248 (15,000)\u00b2 \u00d7 0.01\u03a9 \u00d7 0.1s \u2248 225 kJ<\/div>\n\n    <p>This energy, released as heat in microseconds during arc formation, creates temperatures exceeding 3,000\u00b0C and produces an electromagnetic shock wave. This is more than sufficient to ignite methane (ignition temp 595\u00b0C) and coal dust (ignition temp ~600\u00b0C).<\/p>\n\n    <p><strong>Phase-to-Earth Arc Energy (Type 2S normal case):<\/strong> With 5 A fault current (NER limited) and a fault duration of 50 milliseconds (ECM relay response), the arc energy is approximately:<\/p>\n\n    <div class=\"eq\">E = I\u00b2 \u00d7 R \u00d7 t \u2248 (5)\u00b2 \u00d7 1,270\u03a9 \u00d7 0.05s \u2248 1.6 kJ<\/div>\n\n    <p>This energy is insufficient to sustain an arc in air. The arc self-extinguishes, and no ignition source is created.<\/p>\n\n    <h2 id=\"s7\">7. Earth Leakage Relay Integration: How Type 2S Stops Explosions<\/h2>\n\n    <p>Type 2S cables are engineered specifically to integrate with earth leakage relay (ELR) protection systems used in Australian coal mines.<\/p>\n\n    <p><strong>System Integration:<\/strong> (1) Mine transformer has neutral grounded through NER (typically 5\u201350A), (2) earth leakage relay connected to monitor current through NER, (3) Type 2S cable deployed with all individual screens grounded, (4) if any phase insulation fails, current flows through individual screen to earth, through NER, where ELR detects it, (5) ELR opens main contactor within 50\u2013100ms.<\/p>\n\n    <p><strong>Detection Sensitivity:<\/strong> ELR is designed to trip on very low earth currents (often 0.5\u20135 A). This is feasible because the NER limits maximum fault current to a predictable level. The relay can trip quickly and reliably, before any meaningful arc energy accumulates.<\/p>\n\n    <p><strong>Type 2 Incompatibility:<\/strong> Type 2 cables lack individual screens, so a phase-to-earth fault cannot develop in controlled manner. Mechanical damage tends to involve multiple phases simultaneously, creating the high-energy phase-to-phase fault that the ELR cannot prevent (by the time the main protection clears, explosive energy has already been released).<\/p>\n\n    <h2 id=\"s8\">8. AS\/NZS 1972 Specification: Mandatory Type 2S for 11kV Systems<\/h2>\n\n    <p>AS\/NZS 1972 &#8220;Fixed electric cables\u2014General purpose cables for underground mining&#8221; explicitly mandates individual screening for high-voltage underground systems.<\/p>\n\n    <p><strong>Standard Language:<\/strong> For systems operating at 6 kV and above, individually screened (Type 2S) cable is mandatory. Non-individually screened cables (Type 2) are explicitly prohibited for underground installations where explosion hazard is present.<\/p>\n\n    <p><strong>Regulatory Consequence:<\/strong> Australian mining operations using Type 2 cables on 11kV systems violate AS\/NZS 1972 and are in breach of mining electrical safety regulations. WorkSafe Victoria, NSW Resources Regulator, and Queensland Department of Resources can impose significant penalties.<\/p>\n\n    <h2 id=\"s9\">9. Complete Technical Specification: Type 2S 6.35\/11kV Cable<\/h2>\n\n    <div class=\"tw\">\n      <caption>Table 1 \u2014 AS\/NZS 1972 Type 2S (Individually Screened) 6.35\/11kV Cable Specifications<\/caption>\n      <table>\n        <thead>\n          <tr>\n            <th>No. Cores \u00d7 Cross-Sec (mm\u00b2)<\/th>\n            <th>AWG Equiv.<\/th>\n            <th>Outer \u00d8 (mm)<\/th>\n            <th>Cu Weight (kg\/km)<\/th>\n            <th>Total Weight (kg\/km)<\/th>\n            <th>Ampacity (A)<\/th>\n          <\/tr>\n        <\/thead>\n        <tbody>\n          <tr>\n            <td class=\"g\">3 \u00d7 35<\/td>\n            <td class=\"g\">2<\/td>\n            <td class=\"g\">53\u201356<\/td>\n            <td class=\"g\">1,008<\/td>\n            <td class=\"g\">4,600<\/td>\n            <td class=\"g\">145<\/td>\n          <\/tr>\n          <tr>\n            <td class=\"g\">3 \u00d7 50<\/td>\n            <td class=\"g\">1\/0<\/td>\n            <td class=\"g\">56\u201359<\/td>\n            <td class=\"g\">1,440<\/td>\n            <td class=\"g\">5,300<\/td>\n            <td class=\"g\">170<\/td>\n          <\/tr>\n          <tr>\n            <td class=\"g\">3 \u00d7 70<\/td>\n            <td class=\"g\">2\/0<\/td>\n            <td class=\"g\">60\u201363<\/td>\n            <td class=\"g\">2,016<\/td>\n            <td class=\"g\">6,500<\/td>\n            <td class=\"g\">215<\/td>\n          <\/tr>\n          <tr>\n            <td class=\"g\">3 \u00d7 95<\/td>\n            <td class=\"g\">3\/0<\/td>\n            <td class=\"g\">64\u201368<\/td>\n            <td class=\"g\">2,736<\/td>\n            <td class=\"g\">7,700<\/td>\n            <td class=\"g\">260<\/td>\n          <\/tr>\n          <tr>\n            <td class=\"g\">3 \u00d7 120<\/td>\n            <td class=\"g\">4\/0<\/td>\n            <td class=\"g\">68\u201372<\/td>\n            <td class=\"g\">3,456<\/td>\n            <td class=\"g\">8,900<\/td>\n            <td class=\"g\">295<\/td>\n          <\/tr>\n          <tr>\n            <td class=\"g\">3 \u00d7 150<\/td>\n            <td class=\"g\">300 MCM<\/td>\n            <td class=\"g\">72\u201376<\/td>\n            <td class=\"g\">4,320<\/td>\n            <td class=\"g\">10,200<\/td>\n            <td class=\"g\">335<\/td>\n          <\/tr>\n          <tr>\n            <td class=\"g\">3 \u00d7 185<\/td>\n            <td class=\"g\">350 MCM<\/td>\n            <td class=\"g\">76\u201380<\/td>\n            <td class=\"g\">5,328<\/td>\n            <td class=\"g\">11,800<\/td>\n            <td class=\"g\">385<\/td>\n          <\/tr>\n          <tr>\n            <td class=\"g\">3 \u00d7 240<\/td>\n            <td class=\"g\">500 MCM<\/td>\n            <td class=\"g\">82\u201387<\/td>\n            <td class=\"g\">6,912<\/td>\n            <td class=\"g\">14,300<\/td>\n            <td class=\"g\">445<\/td>\n          <\/tr>\n        <\/tbody>\n      <\/table>\n    <\/div>\n\n    <p><strong>Notes:<\/strong> Ampacity based on air installation, 40\u00b0C ambient, 90\u00b0C conductor temperature. Underground installation requires additional derating per AS\/NZS 3008.1.1 based on cable grouping and thermal environment.<\/p>\n\n    <h2 id=\"s10\">10. Mechanical and Environmental Requirements<\/h2>\n\n    <p><strong>Individual Screen Material:<\/strong> Copper tape (typical) or copper wire braid, connected to earth via the overall SWA armor. Screen continuity is critical\u2014any break in the individual screen defeats the protection mechanism.<\/p>\n\n    <p><strong>SWA Armor (Steel Wire Armour):<\/strong> Galvanized steel wires wound over the insulation, providing mechanical protection and serving as the common earth return path. Typical armor thickness 2.0\u20133.0 mm depending on conductor size.<\/p>\n\n    <p><strong>PVC Sheath:<\/strong> Outer protective layer over the armor. Must be flame-retardant (IEC 60332-1-2) for underground coal mine compliance.<\/p>\n\n    <p><strong>Bending Radius Requirements:<\/strong> Minimum bending radius typically 15\u201320\u00d7 outer diameter for fixed installation (cables do not move once installed in underground mines).<\/p>\n\n    <h2 id=\"s11\">11. Real-World Failure Scenarios: What Happens Without Type 2S<\/h2>\n\n    <p><strong>Historical Accident Scenario (Based on documented coal mine disasters):<\/strong> A Type 2 cable is installed on an 11kV feeder in an Australian underground coal mine. A roof fall occurs, dropping approximately 50 kg of coal rock onto the cable. The external SWA armor is penetrated. The impact crushes the cable, damaging insulation of Phase A and Phase B conductors simultaneously.<\/p>\n\n    <p><strong>Timeline of Catastrophe:<\/strong> (1) T=0: Mechanical impact, Phase A-B insulation rupture, (2) T=5 milliseconds: Phase A-B short circuit initiated, fault current rises to ~12,000 A, (3) T=10 ms: Arc energy ignites cable insulation and sheath, temperature exceeds 2,500\u00b0C, (4) T=15 ms: Cable jacket rupture, copper conductors exposed to coal mine atmosphere containing methane and coal dust, (5) T=20 ms: Methane-air mixture in vicinity of arc reaches ignition temperature, explosion initiated, (6) T=100 ms: Main protection at substation clears the fault\u2014but the explosion has already propagated beyond the cable location, causing shock waves throughout the mine, (7) Result: Death and injury to personnel in the vicinity, potential secondary explosions from dust ignition, mine shutdown.<\/p>\n\n    <p><strong>With Type 2S Cable\u2014Alternative Outcome:<\/strong> Same mechanical impact occurs, but individual screen on Phase A catches the fault current and shunts it to ground before Phase B insulation can be reached. Fault current is limited to 5 A by the neutral earthing resistor. Earth leakage relay detects the 5 A earth current within 50 ms and opens the main contactor. Fault is cleared. No arc, no ignition, no explosion. Cable is damaged but the mine remains safe.<\/p>\n\n    <h2 id=\"s12\">12. Conclusion: Type 2S is Non-Negotiable for Underground Coal Mining<\/h2>\n\n    <p><strong>Summary:<\/strong> The &#8220;S&#8221; in Type 2S stands for individually screened\u2014meaning each phase conductor has its own metallic shield grounded to earth. This single design feature transforms phase-to-phase faults (which release explosion-causing arc energy) into phase-to-earth faults (which are controlled and rapidly detected).<\/p>\n\n    <p><strong>Regulatory Requirement:<\/strong> AS\/NZS 1972 mandates Type 2S for 11kV underground coal mining systems. This is not a recommendation\u2014it is a legal requirement in Australia and New Zealand.<\/p>\n\n    <p><strong>Safety Principle:<\/strong> Type 2S cables, integrated with earth leakage relay protection and neutral earthing resistor current limiting, provide a complete safety system that prevents explosions. Type 2 cables, lacking individual screening, cannot guarantee this protection.<\/p>\n\n    <p>Feichun Special Cable manufactures AS\/NZS 1972 Type 2S cables engineered for all underground coal mining applications. Our technical team ensures that all individual screens are properly designed, earthing is maintained throughout the cable length, and compliance with Australian mining regulations is absolute.<\/p>\n\n  <\/div>\n\n  <section class=\"refs\">\n    <h2>References &#038; Sources<\/h2>\n    <ol class=\"rl\">\n      <li>AS\/NZS 1972:2012, &#8220;Fixed electric cables\u2014General purpose cables for underground mining,&#8221; Standards New Zealand and Standards Australia.<\/li>\n      <li>AS\/NZS 3008.1.1:2017, &#8220;Electrical installations\u2014Selection of cables,&#8221; Standards New Zealand and Standards Australia.<\/li>\n      <li>WorkSafe Victoria, &#8220;Electrical Safety in Mining,&#8221; Mining Industry Code of Practice, 2023.<\/li>\n      <li>Feichun Special Cable Research &#038; Development Team, &#8220;Type 2 vs Type 2S: Individual Screen Design and Explosion Prevention Logic,&#8221; Technical Report, 2024.<\/li>\n    <\/ol>\n  <\/section>\n\n  <div class=\"contact\">\n    <h3>Contact Anhui Feichun Special Cable Co., Ltd.<\/h3>\n    <div class=\"cg\">\n      <div class=\"ci\">\n        <span class=\"lb\">AS\/NZS 1972 Type 2S 11kV Cables<\/span>\n        <a href=\"mailto:tech@feichuncables.com\" rel=\"nofollow\">tech@feichuncables.com<\/a>\n      <\/div>\n      <div class=\"ci\">\n        <span class=\"lb\">Underground Coal Mining Power Distribution<\/span>\n        <a href=\"mailto:mining@feichuncables.com\" rel=\"nofollow\">mining@feichuncables.com<\/a>\n      <\/div>\n      <div class=\"ci\">\n        <span class=\"lb\">Sales &#038; Compliance Documentation<\/span>\n        <a href=\"mailto:sales@feichuncables.com\" rel=\"nofollow\">sales@feichuncables.com<\/a>\n      <\/div>\n      <div class=\"ci\">\n        <span class=\"lb\">WhatsApp \/ WeChat<\/span>\n        <a href=\"https:\/\/wa.me\/8613855123218\" rel=\"nofollow noopener\" target=\"_blank\">+86 138-5512-3218<\/a>\n      <\/div>\n    <\/div>\n  <\/div>\n\n  <footer class=\"ft\">\n    <p>&copy; 2026 Anhui Feichun Special Cable Co., Ltd. \u2014 All rights reserved.<\/p>\n    <p>Building A, Private Science &#038; Technology Park, Hefei Economic and Technological Development Zone, Anhui Province, China.<\/p>\n    <p><strong>SEO Keywords:<\/strong> AS\/NZS 1972 Type 2S, Type 2 vs Type 2S cable, AS\/NZS 1972 11kV, individual screen mining cable, individually screened cable, 11kV underground coal mine cable, phase to earth fault protection, mining cable earth leakage, AS\/NZS standard mining cable, Type 2S specifications, 11kV SWA mining cable, steel wire armoured mine cable, XLPE insulated mining cable, collective screen vs individual screen, mining cable safety standards, underground feeder cable, high voltage mining electrical, electrical engineer mining cable, mining cable ampacity, 11kV cross section mm2, AWG mining cable equivalent, mining cable outer diameter, mining cable copper weight, 11kV 3 core weight per km, medium voltage fixed installation mining, coal mine power distribution, mine load centre cable, flame retardant mining cable, explosion proof cable logic, phase to phase fault prevention, individual copper tape screen, galvanized steel wire armour mining, mining cable bend radius, cable selection mining engineer, Australian mining electrical standards, AS\/NZS 3008 current capacity, 6.35\/11kV cable dimensions, underground substation cable, main power feeder mine, mine shaft cable, mining infrastructure electrical, heavy duty armoured cable, PVC sheathed mining cable, mine site compliance, electrical safety coal mining, core screen fault logic, SWA cable technical data.<\/p>\n  <\/footer>\n\n<\/article>\n<\/body>\n<\/html>\n","protected":false},"excerpt":{"rendered":"The Single Most Important Cable Design Decision in Underground Coal Mining: Whether the cable employs collective screening (Type 2) or individual phase screening (Type 2S). This single engineering choice directly determines whether a mechanical cable failure will result in a phase-to-earth fault (detected and stopped in milliseconds) or a phase-to-phase fault with thousands of amperes of arc current (igniting methane explosions).","protected":false},"author":1,"featured_media":8497,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"csco_singular_sidebar":"left","csco_page_header_type":"title","csco_page_load_nextpost":"","footnotes":""},"categories":[46145,66],"tags":[828,46161,46183,46156,46180,46148,1674,46175,46171,46153,46160,46152,9696,46196,33073,178,37491,46147,46146,46149,46154,46189,33072,46155,46190,46181,46136,6428,46193,46184,4040,46168,46176,10649,46197,44420,46179,36854,46192,46182,1984,3726,46162,46188,37845,5272,46159,46163,14555,46169,4820,46195,46185,46157,8821,2054,46191,1990,2196,46119,46173,44194,2202,2200,1988,46143,46166,46187,46167,46172,46194,5281,46186,46165,1008,46177,46198,14258,46170,46150,46174,46151,46178,46164,7345,46158,1661],"class_list":["post-8496","post","type-post","status-publish","format-standard","has-post-thumbnail","category-as-nzs-1972-electric-cables-underground-coal-mines","category-common-problems-encountered-in-cable-applications","tag-medium-voltage-mining-cable","tag-11kv-3-core-cable-weight","tag-11kv-3-core-weight-per-km","tag-11kv-ampacity","tag-11kv-cross-section-mm2","tag-11kv-feeder-cable","tag-11kv-mining-cable","tag-11kv-swa-mining-cable","tag-11kv-underground-coal-mine-cable","tag-185mm2-mining-cable","tag-350-mcm-11kv-cable","tag-3x185mm2-11kv-cable","tag-6-35-11kv-cable","tag-6-35-11kv-cable-dimensions","tag-as-nzs-1125","tag-as-nzs-1429-1","tag-as-nzs-1972","tag-as-nzs-1972-11kv","tag-as-nzs-1972-cable","tag-as-nzs-1972-type-2s","tag-as-nzs-1972-vs-as-nzs-1802","tag-as-nzs-3008-current-capacity","tag-as-nzs-3808","tag-as-nzs-standard-mining-cable","tag-australian-mining-electrical-standards","tag-awg-mining-cable-equivalent","tag-awg-to-mm2-mining-cable","tag-cable-selection-mining","tag-cable-selection-mining-engineer","tag-caledonian-11kv-mining","tag-caledonian-mining-cable","tag-coal-mine-power-distribution","tag-collective-screen-vs-individual-screen","tag-copper-wire-screen-cable","tag-core-screen-fault-logic","tag-earth-fault-protection-mining","tag-electrical-engineer-mining-cable","tag-electrical-engineering-mining","tag-electrical-safety-coal-mining","tag-explosion-proof-cable-logic","tag-fixed-installation-mining-cable","tag-flame-retardant-mining-cable-2","tag-flame-retardant-pvc-sheath","tag-galvanized-steel-wire-armour-mining","tag-heavy-duty-armoured-cable","tag-heavy-duty-mine-cable","tag-high-voltage-mining-electrical","tag-individual-copper-tape-screen","tag-individual-screen-cable","tag-individual-screen-mining-cable","tag-individually-screened-cable","tag-main-power-feeder-mine","tag-medium-voltage-fixed-installation-mining","tag-mine-load-centre-cable","tag-mine-power-feeder","tag-mine-shaft-cable","tag-mine-site-compliance","tag-mining-cable-ampacity","tag-mining-cable-bend-radius","tag-mining-cable-copper-weight","tag-mining-cable-earth-leakage","tag-mining-cable-outer-diameter","tag-mining-cable-safety-standards","tag-mining-cable-short-circuit-rating","tag-mining-cable-specifications","tag-mining-cable-technical-data","tag-mining-electrical-compliance","tag-mining-infrastructure-electrical","tag-olex-mining-cable","tag-phase-to-earth-fault-protection-2","tag-phase-to-phase-fault-prevention","tag-prysmian-mining-cable","tag-prysmian-type-2s","tag-pvc-sheathed-mining-cable","tag-steel-wire-armoured-cable","tag-steel-wire-armoured-mine-cable","tag-swa-cable-technical-data","tag-swa-mining-cable","tag-type-2-vs-type-2s-cable","tag-type-2s-cable","tag-type-2s-specifications","tag-underground-coal-mine-feeder","tag-underground-feeder-cable","tag-underground-mining-infrastructure","tag-underground-substation-cable","tag-underground-substation-feeder","tag-xlpe-insulated-mining-cable","cs-entry"],"_links":{"self":[{"href":"https:\/\/feichuncables.com\/blog\/wp-json\/wp\/v2\/posts\/8496","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/feichuncables.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/feichuncables.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/feichuncables.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/feichuncables.com\/blog\/wp-json\/wp\/v2\/comments?post=8496"}],"version-history":[{"count":1,"href":"https:\/\/feichuncables.com\/blog\/wp-json\/wp\/v2\/posts\/8496\/revisions"}],"predecessor-version":[{"id":8498,"href":"https:\/\/feichuncables.com\/blog\/wp-json\/wp\/v2\/posts\/8496\/revisions\/8498"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/feichuncables.com\/blog\/wp-json\/wp\/v2\/media\/8497"}],"wp:attachment":[{"href":"https:\/\/feichuncables.com\/blog\/wp-json\/wp\/v2\/media?parent=8496"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/feichuncables.com\/blog\/wp-json\/wp\/v2\/categories?post=8496"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/feichuncables.com\/blog\/wp-json\/wp\/v2\/tags?post=8496"}],"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