{"id":2358,"date":"2026-01-09T11:53:23","date_gmt":"2026-01-09T11:53:23","guid":{"rendered":"https:\/\/cnkuangya.com\/?p=2358"},"modified":"2026-04-24T15:48:57","modified_gmt":"2026-04-24T07:48:57","slug":"dc-fuse-sizing","status":"publish","type":"post","link":"https:\/\/cnkuangya.com\/ja\/blog\/dc-fuse-sizing\/","title":{"rendered":"\u76f4\u6d41\u30d2\u30e5\u30fc\u30ba\u306e\u30b5\u30a4\u30b8\u30f3\u30b0\uff1a\u8a08\u7b97\u6a5f\u3068\u4f8b\u306b\u3088\u308b\u30b9\u30c6\u30c3\u30d7\u30d0\u30a4\u30b9\u30c6\u30c3\u30d7\u30ac\u30a4\u30c9"},"content":{"rendered":"

Introduction: The High Cost of a ‘Close Enough’ Calculation<\/h2>\n\n\n\n

An experienced solar installer, let’s call him Dave, was facing a recurring nightmare. On a 100kW commercial rooftop system he\u2019d completed three months prior, fuses were blowing on perfectly sunny days. The client was losing production, and Dave\u2019s team was wasting time and money on service calls to replace 20A fuses. The initial diagnosis was a bad batch of fuses. But after the third call-out, the real problem became clear. The system was designed with new high-efficiency 550W panels with a short-circuit current (Isc) of 13.9A. Dave’s lead engineer, relying on old habits, had sized the string fuses using a simple 1.25x multiplier, landing on 17.4A and rounding up to a standard 20A fuse.<\/p>\n\n\n\n

\u5f7c\u304c\u898b\u843d\u3068\u3057\u3066\u3044\u305f\u306e\u306f\u3001\u9023\u7d9a\u7684\u306a\u8ca0\u8377\u306e\u4e21\u65b9\u3092\u8003\u616e\u3057\u305f\u3001\u898f\u5247\u3067\u5b9a\u3081\u3089\u308c\u305f\u5b8c\u5168\u306a\u8a08\u7b97\u3060\u3063\u305f\u3002\u00a0\u305d\u3057\u3066<\/em>\u00a0\u5b9f\u4e16\u754c\u306e\u592a\u967d\u653e\u5c04\u7167\u5ea6\u30b9\u30d1\u30a4\u30af\uff08\u592a\u967d\u5149\u3092\u6d74\u3073\u305f\u30d1\u30cd\u30eb\u304c\u4e00\u6642\u7684\u306b\u5b9a\u683c\u3092\u5927\u5e45\u306b\u4e0a\u56de\u308b\u51fa\u529b\u3092\u51fa\u3059\u72b6\u6cc1\uff09\u3002\u305d\u306e\u3088\u3046\u306a\u723d\u3084\u304b\u3067\u660e\u308b\u3044\u5348\u5f8c\u3001\u30a2\u30ec\u30a4\u306e\u96fb\u6d41\u306f\u30d2\u30e5\u30fc\u30ba\u30fb\u30a8\u30ec\u30e1\u30f3\u30c8\u3092\u75b2\u52b4\u3055\u305b\u308b\u306e\u306b\u5341\u5206\u306a\u6642\u9593\u300120A\u3092\u308f\u305a\u304b\u306b\u8d85\u3048\u308b\u7a0b\u5ea6\u3060\u3063\u305f\u3002\u305d\u306e\u305f\u3081\u3001\u30b3\u30f3\u30d0\u30a4\u30ca\u30fc\u30dc\u30c3\u30af\u30b9\u306e\u30d2\u30e5\u30fc\u30ba\u309225A\u306b\u5909\u66f4\u3057\u305f\u3002 \u30d2\u30e5\u30fc\u30ba<\/a>, \u3057\u304b\u3057\u3001\u30af\u30e9\u30a4\u30a2\u30f3\u30c8\u306e\u4e0d\u6e80\u3001\u5229\u76ca\u7387\u306e\u4f4e\u4e0b\u3001\u305d\u3057\u3066\u305b\u3063\u304b\u304f\u5f97\u305f\u6559\u8a13\u3068\u3044\u3046\u30c0\u30e1\u30fc\u30b8\u306f\u5927\u304d\u304b\u3063\u305f\u3002.<\/p>\n\n\n\n

“Close enough” is a dangerous phrase in electrical design. In the world of high-power Direct Current (DC) systems\u2014from utility-scale solar farms to battery energy storage (BESS) and electric vehicle (EV) fast chargers\u2014precise, code-compliant fuse sizing is not a recommendation; it is a non-negotiable pillar of safety, reliability, and financial viability. This guide provides a step-by-step, professional methodology for getting it right, every time.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Part 1: The Fundamentals – Why DC Fusing Demands More Respect<\/h2>\n\n\n\n

Before diving into calculations, it’s crucial to understand why DC overcurrent protection is fundamentally more challenging than its AC counterpart. The difference lies in the physics of an electrical arc.<\/p>\n\n\n\n

In an AC circuit, the current naturally passes through zero 100 or 120 times every second. This zero-crossing provides a momentary opportunity for an arc\u2014the plasma bridge that forms when a fuse element melts\u2014to extinguish. AC fuses are designed to leverage this recurring “off” switch.<\/p>\n\n\n\n

DC\u306f\u5bb9\u8d66\u306a\u3044\u3002\u30bc\u30ed\u30af\u30ed\u30b9\u306f\u306a\u3044\u3002\u76f4\u6d41\u30d2\u30e5\u30fc\u30ba\u304c\u958b\u304f\u3068\u3001\u9023\u7d9a\u3057\u305f\u9ad8\u30a8\u30cd\u30eb\u30ae\u30fc\u306e\u30a2\u30fc\u30af\u304c\u767a\u751f\u3059\u308b\u3002\u3053\u306e\u30a2\u30fc\u30af\u306f\u672c\u8cea\u7684\u306b\u30d7\u30e9\u30ba\u30de\u30b8\u30a7\u30c3\u30c8\u3067\u3042\u308a\u3001\u305d\u306e\u6e29\u5ea6\u306f10,000\u2103\u3092\u8d85\u3048\u308b\u3002\u3053\u308c\u3092\u6d88\u6ec5\u3055\u305b\u308b\u305f\u3081\u306b\u306f\u3001DC\u30d2\u30e5\u30fc\u30ba\u306f\u3001\u305d\u306e\u8981\u6c42\u96fb\u5727\u304c\u30b7\u30b9\u30c6\u30e0\u306e\u96fb\u5727\u3092\u8d85\u3048\u308b\u307e\u3067\u30a2\u30fc\u30af\u3092\u5f15\u304d\u4f38\u3070\u3059\u306e\u306b\u5341\u5206\u306a\u5f37\u5ea6\u3092\u6301\u3061\u3001\u540c\u6642\u306b\u30d7\u30e9\u30ba\u30de\u3092\u51b7\u5374\u3059\u308b\u305f\u3081\u306b\u83ab\u5927\u306a\u71b1\u30a8\u30cd\u30eb\u30ae\u30fc\u3092\u5438\u53ce\u3057\u306a\u3051\u308c\u3070\u306a\u3089\u306a\u3044\u3002\u3053\u306e\u305f\u3081\u3001PV\uff08\u592a\u967d\u5149\u767a\u96fb\uff09\u30d2\u30e5\u30fc\u30ba\u3084\u305d\u306e\u4ed6\u306e\u76f4\u6d41\u5b9a\u683c\u30d2\u30e5\u30fc\u30ba\u306b\u306f\u3001\u7279\u6b8a\u306a\u77f3\u82f1\u7802\u30d5\u30a3\u30e9\u30fc\u304c\u542b\u307e\u308c\u3066\u3044\u308b\u3053\u3068\u304c\u591a\u304f\u3001\u3053\u306e\u77f3\u82f1\u7802\u30d5\u30a3\u30e9\u30fc\u306f\u30d5\u30eb\u30b0\u30e9\u30a4\u30c8\u3068\u547c\u3070\u308c\u308b\u30ac\u30e9\u30b9\u72b6\u306e\u7269\u8cea\u306b\u6eb6\u3051\u3066\u30a2\u30fc\u30af\u3092\u7a92\u606f\u3055\u305b\u307e\u3059\u3002.<\/p>\n\n\n\n

DC \u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u3067 AC \u30d2\u30e5\u30fc\u30ba\u3092\u4f7f\u7528\u3059\u308b\u3053\u3068\u306f\u81f4\u547d\u7684\u306a\u8aa4\u308a\u3067\u3059\u3002\u30d2\u30e5\u30fc\u30ba\u306f\u6545\u969c\u3092\u9664\u53bb\u3067\u304d\u306a\u3044\u53ef\u80fd\u6027\u304c\u9ad8\u304f\u3001\u30a2\u30fc\u30af\u304c\u6301\u7d9a\u3057\u3001\u30d2\u30e5\u30fc\u30ba\u672c\u4f53\u304c\u7206\u767a\u3059\u308b\u53ef\u80fd\u6027\u304c\u3042\u308a\u3001\u91cd\u5927\u306a\u706b\u707d\u306e\u5371\u967a\u6027\u304c\u3042\u308a\u307e\u3059\u3002DC \u30d2\u30e5\u30fc\u30ba\u3092\u6b63\u3057\u304f\u6307\u5b9a\u3059\u308b\u306b\u306f\u30014 \u3064\u306e\u91cd\u8981\u306a\u30d1\u30e9\u30e1\u30fc\u30bf\u3092\u30de\u30b9\u30bf\u30fc\u3059\u308b\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\uff1a<\/p>\n\n\n\n

    \n
  • \u5b9a\u683c\u96fb\u5727\uff08VDC\uff09\uff1a<\/strong>\u00a0The fuse’s voltage rating must be equal to or greater than the maximum system DC voltage. This includes accounting for open-circuit voltage (Voc) at the coldest expected temperatures for solar arrays.<\/li>\n\n\n\n
  • \u9023\u7d9a\u5b9a\u683c\u96fb\u6d41\uff08\u30a2\u30f3\u30da\u30a2\uff09\uff1a<\/strong>\u00a0This is the nameplate value of the fuse (e.g., “15A”). It indicates the amount of current the fuse can carry indefinitely without degrading. It is\u00a0\u306a\u3044<\/em>\u00a0\u3059\u3050\u306b\u5439\u304d\u51fa\u3059\u96fb\u6d41\u3002.<\/li>\n\n\n\n
  • \u906e\u65ad\u5b9a\u683c\uff08kA\uff09\uff1a<\/strong>\u00a0Also known as Breaking Capacity, this is the maximum fault current the fuse can safely interrupt without rupturing. For a battery bank, the prospective short-circuit current can be thousands of amps. The fuse’s interrupting rating must exceed this value.<\/li>\n\n\n\n
  • \u30d2\u30e5\u30fc\u30ba\u901f\u5ea6\uff08\u6642\u9593-\u96fb\u6d41\u66f2\u7dda\uff09\uff1a<\/strong>\u00a0This defines how quickly a fuse opens at different levels of overcurrent. Fuses are not simple on\/off devices. An “ultra-rapid” semiconductor fuse might open in milliseconds to protect sensitive electronics, while a “time-delay” fuse will withstand temporary inrush currents from motors without nuisance blowing. For solar applications, gPV-rated fuses are designed with a specific curve that tolerates irradiance spikes but protects against dangerous reverse currents.<\/li>\n<\/ul>\n\n\n\n

    \u30d1\u30fc\u30c82\uff1a\u30b3\u30a2\u516c\u5f0f\u306e\u89e3\u8aad\uff1aNEC\u3068IEC\u306e\u6bd4\u8f03<\/h2>\n\n\n\n

    The “1.56 multiplier” is a cornerstone of DC fuse sizing in North America, but many professionals misapply it or don’t understand its origin. It’s not an arbitrary number; it’s a safety factor derived directly from the National Electrical Code (NEC).<\/p>\n\n\n\n

    NEC\u306e1.56\u4e57\u306e\u8aac\u660e<\/h3>\n\n\n\n

    1.56\u306e\u500d\u7387\u306f\u3001\u592a\u967d\u5149\u767a\u96fb\u30b7\u30b9\u30c6\u30e0\u306b\u5bfe\u3057\u3066NEC690\u6761\u3067\u7fa9\u52d9\u4ed8\u3051\u3089\u308c\u3066\u3044\u308b\u3088\u3046\u306b\u30012\u3064\u306e\u5225\u3005\u306e125%\u500d\u7387\u3092\u9023\u7d9a\u3057\u3066\u9069\u7528\u3057\u305f\u3082\u306e\u3067\u3042\u308b\u3002.<\/p>\n\n\n\n

      \n
    1. 125% \u306e\u6700\u5927\u96fb\u6d41 (NEC 690.8(A)(1))\uff1a<\/strong>\u00a0This first step is to calculate the “maximum circuit current.” The code recognizes that solar panels under certain conditions (e.g., cold, sunny days with reflected light, or “cloud-edge effect”) can produce more than their rated short-circuit current (Isc). This multiplier establishes a baseline for conductor and OCPD (Overcurrent Protection Device) sizing.\n
        \n
      • \u6700\u5927\u96fb\u6d41 = Isc \u00d7 1.25<\/em><\/li>\n<\/ul>\n<\/li>\n\n\n\n
      • \u9023\u7d9a\u8ca0\u8377\u7528125% (NEC 690.9(B))\uff1a<\/strong>\u00a0The second step treats this “maximum current” as a continuous load. A continuous load is one that can operate for three hours or more, which is standard for a solar array. The NEC requires that overcurrent protection for continuous loads be sized to 125% of that load.\n
          \n
        • \u6700\u5c0f\u30d2\u30e5\u30fc\u30ba\u5b9a\u683c = \u6700\u5927\u96fb\u6d41 \u00d7 1.25<\/em><\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n

          \u3053\u306e2\u3064\u306e\u30b9\u30c6\u30c3\u30d7\u3092\u7d44\u307f\u5408\u308f\u305b\u308b\u3053\u3068\u3067\u3001\u5168\u4f53\u50cf\u304c\u898b\u3048\u3066\u304f\u308b\uff1a<\/p>\n\n\n\n

          \u6700\u5c0f\u30d2\u30e5\u30fc\u30ba\u5b9a\u683c = (Isc \u00d7 1.25) \u00d7 1.25 = Isc \u00d7 1.5625<\/strong><\/p>\n\n\n\n

          \u5b9f\u7528\u4e0a\u3001\u3053\u308c\u306f\u56db\u6368\u4e94\u5165\u3055\u308c\u308b\u3002 1.56<\/strong>. .\u3053\u306e\u6700\u4f4e\u30ec\u30fc\u30c6\u30a3\u30f3\u30b0\u3092\u8a08\u7b97\u3057\u305f\u5f8c\u306f\u3001\u5fc5\u305a\u56db\u6368\u4e94\u5165\u3057\u3066\u304f\u3060\u3055\u3044\u3002 \u4e0a<\/em> \u3092\u6b21\u306e\u6a19\u6e96\u30d2\u30e5\u30fc\u30ba\u30b5\u30a4\u30ba\uff08\u4f8b\u3048\u3070\u300110A\u300115A\u300120A\u300125A\u300130A\uff09\u306b\u5909\u66f4\u3057\u307e\u3059\u3002.<\/p>\n\n\n\n

          IEC\u30a2\u30d7\u30ed\u30fc\u30c1\u3068\u306e\u6bd4\u8f03<\/h3>\n\n\n\n

          NEC \u306f\u660e\u78ba\u306a\u898f\u5b9a\u500d\u7387\u3092\u63d0\u793a\u3057\u3066\u3044\u307e\u3059\u304c\u3001\u56fd\u969b\u898f\u683c IEC 62548 \u306f\u3088\u308a\u67d4\u8edf\u306a\u7bc4\u56f2\u3092\u63d0\u793a\u3057\u3066\u3044\u307e\u3059\u3002IEC \u898f\u683c\u3067\u306f\u3001\u30d2\u30e5\u30fc\u30ba\u5b9a\u683c (I_n) \u306f\u8a2d\u8a08\u96fb\u6d41 (I_B) \u3068\u30b1\u30fc\u30d6\u30eb\u306e\u30a2\u30f3\u30da\u30a2\u5bb9\u91cf (I_z) \u306e\u9593\u306b\u53ce\u307e\u3063\u3066\u3044\u306a\u3051\u308c\u3070\u306a\u3089\u306a\u3044\u3068\u5b9a\u3081\u3066\u3044\u307e\u3059\u3002 I_B \u2266 I_n \u2266 I_z<\/code>.<\/p>\n\n\n\n

          For PV string protection, IEC 62548 recommends sizing the fuse rating between 1.5 and 2.4 times the module’s Isc.<\/p>\n\n\n\n

            \n
          • IEC \u30d2\u30e5\u30fc\u30ba\u306e\u30b5\u30a4\u30b8\u30f3\u30b0\uff1a<\/strong>\u00a0\u6700\u5c0f\u30d2\u30e5\u30fc\u30ba\u5b9a\u683c = Isc \u00d7 (1.5 to 2.4)<\/em><\/li>\n<\/ul>\n\n\n\n

            \u3053\u306e\u7bc4\u56f2\u306b\u3088\u308a\u3001\u8a2d\u8a08\u8005\u306f\u5730\u57df\u306e\u74b0\u5883\u6761\u4ef6\u3001\u6e29\u5ea6\u3001\u7279\u5b9a\u306e\u30e2\u30b8\u30e5\u30fc\u30eb\u7279\u6027\u306b\u57fa\u3065\u3044\u3066\u4fdd\u8b77\u3092\u6700\u9069\u5316\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002\u305f\u3060\u3057\u3001NEC\u7ba1\u8f44\u4e0b\u306e\u30d7\u30ed\u30b8\u30a7\u30af\u30c8\u3067\u306f 1.56\u500d\u306f\u5fc5\u9808\u3002.<\/strong><\/p>\n\n\n\n

            \u30d1\u30fc\u30c83\uff1a\u30b9\u30c6\u30c3\u30d7\u30fb\u30d0\u30a4\u30fb\u30b9\u30c6\u30c3\u30d7\u306e\u30b5\u30a4\u30ba\u8a08\u7b97\u6a5f<\/h2>\n\n\n\n

            \u3053\u308c\u306f\u81ea\u52d5\u5316\u3055\u308c\u305f\u30c4\u30fc\u30eb\u3067\u306f\u306a\u304f\u3001\u3042\u3089\u3086\u308b\u91cd\u8981\u306a\u5909\u6570\u304c\u8003\u616e\u3055\u308c\u3066\u3044\u308b\u3053\u3068\u3092\u78ba\u8a8d\u3059\u308b\u305f\u3081\u306e\u3001\u624b\u52d5\u306b\u3088\u308b6\u6bb5\u968e\u306e\u30d7\u30ed\u30bb\u30b9\u3060\u3068\u8003\u3048\u3066\u304f\u3060\u3055\u3044\u3002\u3053\u306e\u30ef\u30fc\u30af\u30d5\u30ed\u30fc\u306b\u5f93\u3046\u3053\u3068\u3067\u3001\u30a8\u30e9\u30fc\u3092\u9632\u304e\u3001\u5b89\u5168\u3067\u4fe1\u983c\u6027\u306e\u9ad8\u3044\u3001\u30b3\u30fc\u30c9\u306b\u6e96\u62e0\u3057\u305f\u8a2d\u8a08\u306b\u3064\u306a\u304c\u308a\u307e\u3059\u3002.<\/p>\n\n\n\n

            \u30b9\u30c6\u30c3\u30d71\uff1a\u6700\u5927\u8a2d\u8a08\u96fb\u6d41\u306e\u6c7a\u5b9a<\/strong>
            \u56de\u8def\u304c\u6d41\u305b\u308b\u6700\u5927\u9023\u7d9a\u96fb\u6d41\u3092\u7279\u5b9a\u3059\u308b\u3002.<\/p>\n\n\n\n

              \n
            • For solar strings: Use the panel’s short-circuit current (Isc).<\/li>\n\n\n\n
            • For battery banks: Use the inverter’s maximum continuous DC input current.<\/li>\n\n\n\n
            • For DC loads (like EV chargers): Use the equipment’s nameplate maximum DC current rating.<\/li>\n<\/ul>\n\n\n\n

              \u30b9\u30c6\u30c3\u30d72\uff1a\u6e29\u5ea6\u30c7\u30a3\u30ec\u30fc\u30c6\u30a3\u30f3\u30b0\u4fc2\u6570\u306e\u9069\u7528<\/strong>
              Fuses are rated for a specific ambient temperature (usually 25\u00b0C or 40\u00b0C). If they are installed in a hotter environment, like a sun-baked combiner box on a roof, their effective current-carrying capacity is reduced. You must consult the fuse manufacturer’s datasheet for derating curves or tables. For example, a 20A fuse in a 65\u00b0C environment might only have an effective rating of 17.4A. You may need to select a larger fuse to compensate.<\/p>\n\n\n\n

              \u30b9\u30c6\u30c3\u30d73\uff1a\u95a2\u9023\u3059\u308b\u30b3\u30fc\u30c9\u4e57\u6570\u3092\u9069\u7528\u3059\u308b<\/strong>
              \u9069\u7528\u3055\u308c\u308b\u6cd5\u4ee4\u306b\u57fa\u3065\u304d\u3001\u5fc5\u8981\u306a\u5b89\u5168\u4fc2\u6570\u3092\u9069\u7528\u3059\u308b\u3002.<\/p>\n\n\n\n

                \n
              • NEC\u6e96\u62e0\u306e\u30bd\u30fc\u30e9\u30fc\u7528\uff1aIsc\u306b1.56\u3092\u639b\u3051\u308b\u3002.<\/li>\n\n\n\n
              • NEC\u306b\u57fa\u3065\u304f\u305d\u306e\u4ed6\u306e\u9023\u7d9aDC\u8ca0\u8377\u306e\u5834\u5408\uff1a\u6700\u5927\u8a2d\u8a08\u96fb\u6d41\u306b1.25\u3092\u4e57\u3058\u308b\u3002.<\/li>\n\n\n\n
              • IEC\u30d7\u30ed\u30b8\u30a7\u30af\u30c8\u306e\u5834\u5408\uff1a\u8a2d\u8a08\u306b\u5fdc\u3058\u30661.5\uff5e2.4\u306e\u500d\u7387\u3092\u4f7f\u7528\u3059\u308b\u3002.<\/li>\n<\/ul>\n\n\n\n

                \u30b9\u30c6\u30c3\u30d7 4\uff1a\u6b21\u306e\u6a19\u6e96\u30d2\u30e5\u30fc\u30ba\u30b5\u30a4\u30ba\u3092\u9078\u629e\u3059\u308b<\/strong>
                After applying multipliers, you’ll have a minimum required fuse rating. You must select the next \u6a19\u6e96<\/em> \u8a08\u7b97\u5024\u3068\u540c\u7b49\u304b\u305d\u308c\u4ee5\u4e0a\u306e\u5e02\u8ca9\u306e\u30d2\u30e5\u30fc\u30ba\u30b5\u30a4\u30ba\u3092\u304a\u9078\u3073\u304f\u3060\u3055\u3044\u3002\u4f8b\u3048\u3070\u3001\u8a08\u7b97\u306e\u7d50\u679c\u3001\u6700\u5c0f\u5b9a\u683c\u304c 22.54A \u3067\u3042\u3063\u305f\u5834\u5408\u300125A \u306e\u30d2\u30e5\u30fc\u30ba\u3092\u9078\u629e\u3059\u308b\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\u3002.<\/p>\n\n\n\n

                \u30b9\u30c6\u30c3\u30d7 5\uff1a\u5c0e\u4f53\u304a\u3088\u3073\u6a5f\u5668\u306e\u4fdd\u8b77\u306e\u78ba\u8a8d<\/strong>
                \u30d2\u30e5\u30fc\u30ba\u306b\u306f\u3001\u96fb\u7dda\u306e\u4fdd\u8b77\u3068\u6a5f\u5668\u306e\u4fdd\u8b77\u3068\u3044\u30462\u3064\u306e\u5f79\u5272\u304c\u3042\u308b\u3002.<\/p>\n\n\n\n

                  \n
                • \u30ef\u30a4\u30e4\u30fc\u306e\u4fdd\u8b77\uff1a<\/strong>\u00a0\u30d2\u30e5\u30fc\u30ba\u306e\u5b9a\u683c\u306f\u3001\u63a5\u7d9a\u3055\u308c\u3066\u3044\u308b\u30ef\u30a4\u30e4\u30fc\u306e\u8010\u529b\u3092\u8d85\u3048\u3066\u306f\u306a\u308a\u307e\u305b\u3093\u3002\u5b9a\u683c20A\u306e\u96fb\u7dda\u306b30A\u306e\u30d2\u30e5\u30fc\u30ba\u3092\u4f7f\u7528\u3059\u308b\u3068\u706b\u707d\u306e\u5371\u967a\u304c\u3042\u308a\u307e\u3059\u3002.<\/li>\n\n\n\n
                • \u6a5f\u5668\u306e\u4fdd\u8b77\uff1a<\/strong>\u00a0The fuse rating must not exceed the maximum OCPD rating specified by the equipment manufacturer. Solar panels, for instance, have a “Maximum Series Fuse Rating” on their datasheet (typically 15A to 30A). Exceeding this voids the warranty and can lead to module damage.<\/li>\n<\/ul>\n\n\n\n

                  \u30b9\u30c6\u30c3\u30d76\uff1a\u906e\u65ad\u5b9a\u683c\uff08kA\uff09\u306e\u78ba\u8a8d<\/strong>
                  Finally, verify that the fuse’s Interrupting Rating (kA) is greater than the available short-circuit current at that point in the system. This is especially critical for battery systems, which can deliver massive fault currents. A quick estimate for a battery’s prospective short-circuit current (I_sc) is I_sc = \u30d0\u30c3\u30c6\u30ea\u30fc\u96fb\u5727 \/ \u30eb\u30fc\u30d7\u7dcf\u62b5\u6297\u5024<\/code>. .\u8a08\u7b97\u3055\u308c\u305fI_sc\u304c16,000A\uff0816kA\uff09\u306e\u5834\u5408\u300110kA\u306e\u906e\u65ad\u5b9a\u683c\u3092\u6301\u3064\u30d2\u30e5\u30fc\u30ba\u3067\u306f\u4e0d\u5341\u5206\u3067\u3042\u308a\u3001\u6fc0\u3057\u304f\u6545\u969c\u3059\u308b\u53ef\u80fd\u6027\u304c\u3042\u308b\u3002.<\/p>\n\n\n\n

                  \u30d1\u30fc\u30c84\uff1a\u8a08\u7b97\u306b\u3088\u308b\u5fdc\u7528\u4f8b<\/h2>\n\n\n\n

                  Let’s apply this six-step process to three common high-power DC applications.<\/p>\n\n\n\n

                  \"\"<\/figure>\n\n\n\n

                  A.\u592a\u967d\u5149\u767a\u96fb\u30b7\u30b9\u30c6\u30e0\uff08\u30b9\u30c8\u30ea\u30f3\u30b0\uff06\u30b3\u30f3\u30d0\u30a4\u30ca\u30fc\u30d2\u30e5\u30fc\u30ba\uff09<\/h3>\n\n\n\n

                  3\u3064\u4ee5\u4e0a\u306e\u30b9\u30c8\u30ea\u30f3\u30b0\u304c\u4e26\u5217\u306b\u63a5\u7d9a\u3055\u308c\u305f\u30bd\u30fc\u30e9\u30fc\u30a2\u30ec\u30a4\u306e\u5834\u5408\u3001NEC690.9(A)\u306f\u5404\u30b9\u30c8\u30ea\u30f3\u30b0\u306b\u500b\u5225\u306e\u30d2\u30e5\u30fc\u30ba\u3092\u5fc5\u8981\u3068\u3059\u308b\u3002\u3053\u308c\u306b\u3088\u308a\u30011\u3064\u306e\u30b9\u30c8\u30ea\u30f3\u30b0\u306b\u969c\u5bb3\u304c\u767a\u751f\u3057\u3066\u3082\u3001\u5065\u5168\u306a\u30b9\u30c8\u30ea\u30f3\u30b0\u304b\u3089\u5927\u91cf\u306e\u9006\u96fb\u6d41\u304c\u6d41\u308c\u308b\u306e\u3092\u9632\u3050\u3053\u3068\u304c\u3067\u304d\u308b\u3002.<\/p>\n\n\n\n

                  \u30b7\u30ca\u30ea\u30aa<\/strong> 450W\u30d1\u30cd\u30eb\u3092\u4f7f\u7528\u3057\u305f\u5546\u696d\u7528\u5c4b\u4e0a\u30b7\u30b9\u30c6\u30e0\u306e\u30b9\u30c8\u30ea\u30f3\u30b0\u30d2\u30e5\u30fc\u30ba\u3092\u8a2d\u8a08\u3002.<\/p>\n\n\n\n

                    \n
                  • \u30d1\u30cd\u30eb\u30fb\u30c7\u30fc\u30bf\u30b7\u30fc\u30c8 Isc\uff1a12.8A<\/li>\n\n\n\n
                  • Panel “Maximum Series Fuse Rating”: 25A<\/li>\n\n\n\n
                  • \u30ef\u30a4\u30e4\u30fc10 AWG PV\u30ef\u30a4\u30e4\u30fc\uff08\u5b9a\u683c40A\uff09<\/li>\n\n\n\n
                  • \u30b3\u30f3\u30d0\u30a4\u30ca\u30fc\u30dc\u30c3\u30af\u30b9\u306e\u5468\u56f2\u6e29\u5ea650\u00b0C<\/li>\n\n\n\n
                  • Fuse Manufacturer’s Derating at 50\u00b0C: 0.92<\/li>\n<\/ul>\n\n\n\n

                    \u8a08\u7b97\uff1a<\/strong><\/p>\n\n\n\n

                      \n
                    1. \u6700\u5927\u8a2d\u8a08\u96fb\u6d41\uff1a<\/strong>\u00a0\u57fa\u672c\u306f\u30d1\u30cd\u30ebIsc\u3067\u3042\u308b\uff1a\u00a012.8A<\/strong>.<\/li>\n\n\n\n
                    2. \u6e29\u5ea6\u30c7\u30a3\u30ec\u30fc\u30c6\u30a3\u30f3\u30b0\uff1a<\/strong>\u00a0\u305d\u306e\u30d2\u30e5\u30fc\u30ba\u306e\u30b5\u30a4\u30ba\u3092\u898b\u3064\u3051\u308b\u5fc5\u8981\u304c\u3042\u308b\u3001,\u00a0\u305d\u306e\u5f8c<\/em>\u00a0derating, still meets our code requirement. We’ll apply the derating factor later during verification.<\/li>\n\n\n\n
                    3. \u30b3\u30fc\u30c9\u30fb\u30de\u30eb\u30c1\u30d7\u30e9\u30a4\u30e4\u30fc\uff08NEC\uff09\uff1a<\/strong>\n
                        \n
                      • \u6700\u4f4e\u5fc5\u8981\u5b9a\u683c = 12.8A \u00d7 1.56 = 19.97A<\/code><\/li>\n<\/ul>\n<\/li>\n\n\n\n
                      • \u6a19\u6e96\u30d2\u30e5\u30fc\u30ba\u30b5\u30a4\u30ba\u3092\u9078\u629e\u3057\u3066\u304f\u3060\u3055\u3044\uff1a<\/strong>\u00a019.97A\u306e\u6b21\u306e\u6a19\u6e96\u30b5\u30a4\u30ba\u306f\u00a020A<\/strong>.<\/li>\n\n\n\n
                      • \u30d7\u30ed\u30c6\u30af\u30b7\u30e7\u30f3\u3092\u78ba\u8a8d\u3059\u308b\uff1a<\/strong>\n
                          \n
                        • \u6e29\u5ea6\u30c1\u30a7\u30c3\u30af\uff1a<\/strong>\u00a0Now, let’s see if the 20A fuse is sufficient at 50\u00b0C.\n
                            \n
                          • \u6709\u52b9\u30d2\u30e5\u30fc\u30ba\u5b9a\u683c = 20A \u00d7 0.92\uff08\u30c7\u30a3\u30ec\u30fc\u30c6\u30a3\u30f3\u30b0\u4fc2\u6570\uff09 = 18.4A<\/code><\/li>\n\n\n\n
                          • \u3053\u308c\u306f\u00a0\u672a\u6e80<\/em>\u00a0\u79c1\u305f\u3061\u304c\u8981\u6c42\u3059\u308b\u6700\u4f4e19.97A\u3067\u3059\u300220A\u306e\u30d2\u30e5\u30fc\u30ba\u306f\u5c0f\u3055\u3059\u304e\u3001\u8ff7\u60d1\u306a\u30c8\u30ea\u30c3\u30d7\u3092\u5f15\u304d\u8d77\u3053\u3057\u307e\u3059\u3002.<\/li>\n<\/ul>\n<\/li>\n\n\n\n
                          • \u6539\u8a02\u3055\u308c\u305f\u30bb\u30ec\u30af\u30b7\u30e7\u30f3\uff1a<\/strong>\u00a0\u6b21\u306e\u30b5\u30a4\u30ba\u3092\u9078\u3070\u306a\u3051\u308c\u3070\u306a\u3089\u306a\u3044\u3002\u00a025A\u30d2\u30e5\u30fc\u30ba<\/strong>.\n
                              \n
                            • \u6709\u52b9\u30d2\u30e5\u30fc\u30ba\u5b9a\u683c = 25A \u00d7 0.92 = 23A<\/code><\/li>\n\n\n\n
                            • \u3053\u308c\u306f19.97A\u3088\u308a\u5927\u304d\u3044\u306e\u3067\u3001\u3053\u306e\u9ad8\u6e29\u74b0\u5883\u3067\u306f25A\u306e\u30d2\u30e5\u30fc\u30ba\u304c\u6b63\u3057\u3044\u3002.<\/li>\n<\/ul>\n<\/li>\n\n\n\n
                            • \u30ef\u30a4\u30e4\u30fc\u306e\u4fdd\u8b77\uff1a<\/strong>\u00a025A\u306e\u30d2\u30e5\u30fc\u30ba\u5b9a\u683c\u306f\u300110 AWG\u30ef\u30a4\u30e4\u30fc\u306e40A\u8010\u529b\u3092\u306f\u308b\u304b\u306b\u4e0b\u56de\u3063\u3066\u3044\u307e\u3059\u3002\u2713<\/li>\n\n\n\n
                            • \u6a5f\u5668\u306e\u4fdd\u8b77\uff1a<\/strong>\u00a0The 25A fuse rating is equal to the panel’s “Maximum Series Fuse Rating” of 25A. \u2713<\/li>\n<\/ul>\n<\/li>\n\n\n\n
                            • \u906e\u65ad\u5b9a\u683c\u3092\u30c1\u30a7\u30c3\u30af\u3059\u308b\uff1a<\/strong>\u00a0\u30b9\u30c8\u30ea\u30f3\u30b0\u30ec\u30d9\u30eb\u306e\u30d5\u30a9\u30eb\u30c8\u306e\u5834\u5408\u3001\u5229\u7528\u53ef\u80fd\u306a\u30d5\u30a9\u30eb\u30c8\u96fb\u6d41\u306f\u3001\u4ed6\u306e\u4e26\u5217\u30b9\u30c8\u30ea\u30f3\u30b0\u304b\u3089\u306eIsc\u306e\u5408\u8a08\u3067\u3042\u308b\u3002\u5408\u8a0810\u500b\u306e\u30b9\u30c8\u30ea\u30f3\u30b0\u304c\u3042\u308b\u5834\u5408\u3001\u6700\u5927\u6545\u969c\u96fb\u6d41\u306f\u6b21\u306e\u3088\u3046\u306b\u306a\u308b\u3002\u00a09\u30b9\u30c8\u30ea\u30f3\u30b0\u30b9\u00d712.8A\u2252115A<\/code>. .\u6a19\u6e96\u7684\u306a gPV \u30d2\u30e5\u30fc\u30ba\u306e\u906e\u65ad\u5b9a\u683c\u306f 10kA \u4ee5\u4e0a\u3067\u3042\u308a\u3001\u5341\u5206\u306a\u6027\u80fd\u3092\u5099\u3048\u3066\u3044\u307e\u3059\u3002\u2713<\/li>\n<\/ol>\n\n\n\n

                              \u6700\u7d42\u9078\u8003\uff1a<\/strong> 25A\u30011000VDC gPV\u5b9a\u683c\u30d2\u30e5\u30fc\u30ba\u3002.<\/strong><\/p>\n\n\n\n

                              B.\u84c4\u96fb\u6c60\u30b7\u30b9\u30c6\u30e0\uff08BESS\uff09<\/h3>\n\n\n\n

                              \u5927\u898f\u6a21\u306a\u30ea\u30c1\u30a6\u30e0\u30a4\u30aa\u30f3\u30d0\u30c3\u30c6\u30ea\u30fc\u30d0\u30f3\u30af\u306e\u30d2\u30e5\u30fc\u30ba\u306f\u3001\u4e3b\u306b\u58ca\u6ec5\u7684\u306a\u77ed\u7d61\u304b\u3089\u4fdd\u8b77\u3059\u308b\u3053\u3068\u3067\u3059\u3002\u30d2\u30e5\u30fc\u30ba\u306f\u4f55\u4e07\u30a2\u30f3\u30da\u30a2\u3082\u306e\u96fb\u6d41\u3092\u906e\u65ad\u3067\u304d\u306a\u3051\u308c\u3070\u306a\u308a\u307e\u305b\u3093\u3002.<\/p>\n\n\n\n

                              \u30b7\u30ca\u30ea\u30aa<\/strong> 5,000W\u30a4\u30f3\u30d0\u30fc\u30bf\u30fc\/\u30c1\u30e3\u30fc\u30b8\u30e3\u30fc\u306b\u63a5\u7d9a\u3055\u308c\u305f48V\u3001400Ah LiFePO4\u30d0\u30c3\u30c6\u30ea\u30fc\u30d0\u30f3\u30af\u7528\u306e\u30e1\u30a4\u30f3DC\u30d2\u30e5\u30fc\u30ba\u3092\u9078\u629e\u3057\u307e\u3059\u3002.<\/p>\n\n\n\n

                                \n
                              • \u30a4\u30f3\u30d0\u30fc\u30bf\u30fc\u6700\u5927\u9023\u7d9a\u76f4\u6d41\u96fb\u6d41\uff1a125A<\/li>\n\n\n\n
                              • \u30a4\u30f3\u30d0\u30fc\u30bf\u30fc\u52b9\u7387: 95%<\/li>\n\n\n\n
                              • \u6700\u4f4e\u30d0\u30c3\u30c6\u30ea\u30fc\u52d5\u4f5c\u96fb\u5727\uff1a44V<\/li>\n\n\n\n
                              • \u4e88\u60f3\u77ed\u7d61\u96fb\u6d41\u306e\u8a08\u7b97\uff08\u30d0\u30c3\u30c6\u30ea\u30fc\u306e\u4ed5\u69d8\u3068\u30b1\u30fc\u30d6\u30eb\u62b5\u6297\u304b\u3089\uff09\uff1a\u00a018,000A (18kA)<\/strong><\/li>\n\n\n\n
                              • \u30ef\u30a4\u30e4\u30fc\uff1a2\/0 AWG\uff08\u5b9a\u683c190A\uff09<\/li>\n<\/ul>\n\n\n\n

                                \u8a08\u7b97\uff1a<\/strong><\/p>\n\n\n\n

                                  \n
                                1. \u6700\u5927\u8a2d\u8a08\u96fb\u6d41\uff1a<\/strong>\u00a0We must calculate the inverter’s max current draw at the lowest battery voltage, where current is highest.\n
                                    \n
                                  • \u6700\u5927\u6d88\u8cbb\u96fb\u529b = 5000W \/ 0.95\uff08\u52b9\u7387\uff09 = 5263W<\/code><\/li>\n\n\n\n
                                  • \u6700\u5927DC\u96fb\u6d41 = 5263W \/ 44V\uff08\u4f4e\u96fb\u5727\uff09 = 119.6A<\/code><\/li>\n<\/ul>\n<\/li>\n\n\n\n
                                  • \u6e29\u5ea6\u30c7\u30a3\u30ec\u30fc\u30c6\u30a3\u30f3\u30b0\uff1a<\/strong>\u00a0\u30d2\u30e5\u30fc\u30ba\u304c\u7ba1\u7406\u3055\u308c\u305f\u5c4b\u5185\u74b0\u5883\uff0825\u2103\uff09\u306b\u3042\u308b\u3068\u4eee\u5b9a\u3059\u308b\u3068\u3001\u30c7\u30a3\u30ec\u30fc\u30c6\u30a3\u30f3\u30b0\u306f\u5fc5\u8981\u306a\u3044\u3002.<\/li>\n\n\n\n
                                  • \u30b3\u30fc\u30c9\u30fb\u30de\u30eb\u30c1\u30d7\u30e9\u30a4\u30e4\u30fc\uff08NEC\uff09\uff1a<\/strong>\u00a0\u3053\u308c\u306f\u9023\u7d9a\u8ca0\u8377\u306a\u306e\u3067\u30011.25\u500d\u306e\u500d\u7387\u3092\u4f7f\u7528\u3059\u308b\u3002.\n
                                      \n
                                    • \u6700\u4f4e\u5fc5\u8981\u5b9a\u683c = 119.6A \u00d7 1.25 = 149.5A<\/code><\/li>\n<\/ul>\n<\/li>\n\n\n\n
                                    • \u6a19\u6e96\u30d2\u30e5\u30fc\u30ba\u30b5\u30a4\u30ba\u3092\u9078\u629e\u3057\u3066\u304f\u3060\u3055\u3044\uff1a<\/strong>\u00a0\u6b21\u306e\u6a19\u6e96\u30b5\u30a4\u30ba\u306f\u00a0150A<\/strong>.<\/li>\n\n\n\n
                                    • \u30d7\u30ed\u30c6\u30af\u30b7\u30e7\u30f3\u3092\u78ba\u8a8d\u3059\u308b\uff1a<\/strong>\n
                                        \n
                                      • \u30ef\u30a4\u30e4\u30fc\u306e\u4fdd\u8b77\uff1a<\/strong>\u00a0150A \u306e\u30d2\u30e5\u30fc\u30ba\u5b9a\u683c\u306f\u30012\/0 \u30ef\u30a4\u30e4\u306e 190A \u306e\u30a2\u30f3\u30da\u30a2\u5bb9\u91cf\u3092\u4e0b\u56de\u3063\u3066\u3044\u307e\u3059\u3002\u2713<\/li>\n\n\n\n
                                      • \u6a5f\u5668\u306e\u4fdd\u8b77\uff1a<\/strong>\u00a0150A\u30d2\u30e5\u30fc\u30ba\u306f\u3001\u6700\u5927\u9023\u7d9a\u96fb\u6d41125A\u7528\u306b\u8a2d\u8a08\u3055\u308c\u305f\u30a4\u30f3\u30d0\u30fc\u30bf\u3092\u4fdd\u8b77\u3057\u307e\u3059\u3002\u2713<\/li>\n<\/ul>\n<\/li>\n\n\n\n
                                      • \u906e\u65ad\u5b9a\u683c\u3092\u30c1\u30a7\u30c3\u30af\u3059\u308b\uff1a<\/strong>\u00a0\u4e88\u60f3\u3055\u308c\u308b\u6545\u969c\u96fb\u6d41\u306f18kA\u3067\u3042\u308b\u3002\u3053\u308c\u4ee5\u4e0a\u306e\u906e\u65ad\u5b9a\u683c\u3092\u6301\u3064\u30d2\u30e5\u30fc\u30ba\u304c\u5fc5\u8981\u3067\u3042\u308b\u3002\u6a19\u6e96\u7684\u306aANL\u30d2\u30e5\u30fc\u30ba\u3084MEGA\u30d2\u30e5\u30fc\u30ba\u306f\u5b9a\u683c\u304c2\uff5e6kA\u3057\u304b\u306a\u3044\u3053\u3068\u304c\u591a\u304f\u3001\u4e0d\u5411\u304d\u3067\u3059\u3002\u306e\u3088\u3046\u306a\u9ad8\u906e\u65ad\u5bb9\u91cf\u306e\u30d2\u30e5\u30fc\u30ba\u3092\u4f7f\u7528\u3059\u308b\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\u3002\u00a0\u30af\u30e9\u30b9T\u30d2\u30e5\u30fc\u30ba<\/strong>. .\u30af\u30e9\u30b9 T \u30d2\u30e5\u30fc\u30ba\u306e\u906e\u65ad\u5b9a\u683c\u306f 20kA \uff5e 200kA \u3067\u3059\u300220kA \u5b9a\u683c\u306e\u30af\u30e9\u30b9 T \u30d2\u30e5\u30fc\u30ba\u306f\u5b89\u5168\u306a\u9078\u629e\u3067\u3059\u3002.<\/li>\n<\/ol>\n\n\n\n

                                        \u6700\u7d42\u9078\u8003\uff1a<\/strong> 150A\u3001\u30af\u30e9\u30b9T\u30d2\u30e5\u30fc\u30ba\uff08\u226520kA\u906e\u65ad\u5b9a\u683c\uff09\u3002.<\/strong><\/p>\n\n\n\n

                                        C.DC\u6025\u901f\u5145\u96fb\u5668\uff08EVSE\uff09<\/h3>\n\n\n\n

                                        DC\u6025\u901f\u5145\u96fb\u5668\u306f\u3001\u904e\u96fb\u6d41\u306b\u3088\u3063\u3066\u30de\u30a4\u30af\u30ed\u79d2\u5358\u4f4d\u3067\u7834\u58ca\u3055\u308c\u308b\u53ef\u80fd\u6027\u306e\u3042\u308b\u9ad8\u611f\u5ea6\u30d1\u30ef\u30fc\u30a8\u30ec\u30af\u30c8\u30ed\u30cb\u30af\u30b9\uff08IGBT\u3084SiC MOSFET\uff09\u3092\u642d\u8f09\u3057\u3066\u3044\u308b\u70b9\u304c\u7279\u5fb4\u3067\u3042\u308b\u3002\u3053\u3053\u3067\u306e\u4fdd\u8b77\u306f\u3001\u96fb\u7dda\u706b\u707d\u306e\u9632\u6b62\u3068\u3044\u3046\u3088\u308a\u3082\u3001\u9ad8\u4fa1\u306a\u534a\u5c0e\u4f53\u30e2\u30b8\u30e5\u30fc\u30eb\u306e\u4fdd\u8b77\u304c\u91cd\u8981\u3067\u3042\u308b\u3002\u305d\u306e\u305f\u3081\u306b\u306f\u8d85\u9ad8\u901f\u30d2\u30e5\u30fc\u30ba\u304c\u5fc5\u8981\u3067\u3059\u3002.<\/p>\n\n\n\n

                                        \u30b7\u30ca\u30ea\u30aa<\/strong> 150kW DC \u6025\u901f\u5145\u96fb\u5668\u306e 50kW \u30d1\u30ef\u30fc\u30e2\u30b8\u30e5\u30fc\u30eb 1 \u500b\u306b\u5bfe\u5fdc\u3059\u308b DC \u51fa\u529b\u30d2\u30e5\u30fc\u30ba\u306e\u30b5\u30a4\u30ba\u3002.<\/p>\n\n\n\n

                                          \n
                                        • \u30e2\u30b8\u30e5\u30fc\u30eb\u51fa\u529b\uff1a50kW<\/li>\n\n\n\n
                                        • DC\u51fa\u529b\u96fb\u5727\u7bc4\u56f2\uff1a200-1000VDC<\/li>\n\n\n\n
                                        • IGBT\u30e2\u30b8\u30e5\u30fc\u30eb\u8010\u91cf\uff08I\u00b2t\uff09\uff1a50,000 A\u00b2s<\/li>\n\n\n\n
                                        • DC\u30d0\u30b9\u304b\u3089\u306e\u898b\u8fbc\u307f\u77ed\u7d61\uff1a50kA<\/li>\n<\/ul>\n\n\n\n

                                          \u8a08\u7b97\uff1a<\/strong><\/p>\n\n\n\n

                                            \n
                                          1. \u6700\u5927\u8a2d\u8a08\u96fb\u6d41\uff1a<\/strong>\u00a0\u96fb\u6d41\u306f\u6700\u4f4e\u96fb\u5727\u3067\u6700\u3082\u5927\u304d\u304f\u306a\u308b\u3002\u5145\u96fb\u5668\u304c\u305d\u306e\u96fb\u5727\u7bc4\u56f2\u5168\u4f53\u306750kW\u3092\u4f9b\u7d66\u3067\u304d\u308b\u3068\u4eee\u5b9a\u3059\u308b\uff1a\n
                                              \n
                                            • \u6700\u5927\u96fb\u6d41 = 50,000W \/ 200V = 250A<\/code><\/li>\n<\/ul>\n<\/li>\n\n\n\n
                                            • \u6e29\u5ea6\u30c7\u30a3\u30ec\u30fc\u30c6\u30a3\u30f3\u30b0\uff1a<\/strong>\u00a0These modules are fan-cooled, but for reliability, we’ll use the manufacturer’s guidance, which typically suggests sizing the fuse rating at 1.2-1.5x the continuous load. We will use a 1.4x factor.<\/li>\n\n\n\n
                                            • \u30b3\u30fc\u30c9\u30de\u30eb\u30c1\u30d7\u30e9\u30a4\u30e4\u30fc\uff1a<\/strong>\u00a0\u30e1\u30fc\u30ab\u30fc\u306b\u3088\u308b1.4\u500d\u306e\u30b5\u30a4\u30b8\u30f3\u30b0\u4fc2\u6570\u306f\u3001\u5fc5\u8981\u306a\u5b89\u5168\u30de\u30fc\u30b8\u30f3\u3092\u3059\u3079\u3066\u8003\u616e\u3057\u3066\u3044\u308b\u3002.\n
                                                \n
                                              • \u76ee\u6a19\u30d2\u30e5\u30fc\u30ba\u5b9a\u683c = 250A \u00d7 1.4 = 350A<\/code><\/li>\n<\/ul>\n<\/li>\n\n\n\n
                                              • \u6a19\u6e96\u30d2\u30e5\u30fc\u30ba\u30b5\u30a4\u30ba\u3092\u9078\u629e\u3057\u3066\u304f\u3060\u3055\u3044\uff1a<\/strong>\u00a0A\u00a0350A<\/strong>\u00a0\u534a\u5c0e\u4f53\u30d2\u30e5\u30fc\u30ba\u306f\u6a19\u6e96\u7684\u306a\u30b5\u30a4\u30ba\u3067\u3042\u308b\u3002.<\/li>\n\n\n\n
                                              • \u30d7\u30ed\u30c6\u30af\u30b7\u30e7\u30f3\u3092\u78ba\u8a8d\u3059\u308b\uff1a<\/strong>\u00a0Here, the most critical verification is the I\u00b2t (let-through energy) rating. The fuse’s total clearing I\u00b2t must be\u00a0\u5c11\u306a\u3044<\/em>\u00a0than the IGBT’s withstand rating.\n
                                                  \n
                                                • 350A\u30011000VDC\u306e\u8d85\u9ad8\u901f\u30d2\u30e5\u30fc\u30ba\u306e\u30c7\u30fc\u30bf\u30b7\u30fc\u30c8\u3092\u53c2\u7167\u3059\u308b\u3068\u30011000V\u3067\u306e\u30af\u30ea\u30a2\u30ea\u30f3\u30b0I\u00b2t\u306f\u301c38,000A\u00b2s\u3067\u3042\u308b\u3002.<\/li>\n\n\n\n
                                                • 38,000 A\u00b2s < 50,000 A\u00b2s<\/code>. .\u30d2\u30e5\u30fc\u30ba\u306f IGBT \u3092\u4fdd\u8b77\u3059\u308b\u3002\u2713<\/li>\n<\/ul>\n<\/li>\n\n\n\n
                                                • \u906e\u65ad\u5b9a\u683c\u3092\u30c1\u30a7\u30c3\u30af\u3059\u308b\uff1a<\/strong>\u00a0\u4f7f\u7528\u53ef\u80fd\u306a\u6545\u969c\u96fb\u6d41\u306f 50kA \u3067\u3042\u308b\u3002\u9ad8\u901f\u534a\u5c0e\u4f53\u30d2\u30e5\u30fc\u30ba\u306b\u306f\u300150kA\u3001100kA\u3001\u307e\u305f\u306f\u305d\u308c\u4ee5\u4e0a\u306e\u906e\u65ad\u5b9a\u683c\u306e\u3082\u306e\u304c\u3042\u308a\u307e\u3059\u3002\u306e\u5b9a\u683c\u306e\u3082\u306e\u3092\u9078\u629e\u3057\u306a\u3051\u308c\u3070\u306a\u3089\u306a\u3044\u3002\u00a0\u5c11\u306a\u304f\u3068\u308250kA<\/strong>.<\/li>\n<\/ol>\n\n\n\n

                                                  \u6700\u7d42\u9078\u8003\uff1a<\/strong> 350A\u30011000VDC aR\u5b9a\u683c\uff08\u534a\u5c0e\u4f53\uff09\u30d2\u30e5\u30fc\u30ba\u3001\u226550kA\u906e\u65ad\u5b9a\u683c\u304a\u3088\u3073I\u00b2t < 50,000 A\u00b2s\u3002.<\/strong><\/p>\n\n\n\n

                                                  \u30d1\u30fc\u30c85\uff1a\u3088\u304f\u3042\u308b\u843d\u3068\u3057\u7a74\u3068\u305d\u306e\u907f\u3051\u65b9<\/h2>\n\n\n\n

                                                  Even with a solid process, common mistakes can compromise a system’s safety and reliability. Here is a summary of the most frequent errors and how to prevent them.<\/p>\n\n\n\n

                                                  \u843d\u3068\u3057\u7a74<\/th>Why It’s Dangerous<\/th>\u305d\u308c\u3092\u907f\u3051\u308b\u306b\u306f<\/th><\/tr>
                                                  \u76f4\u6d41\u56de\u8def\u3067\u306eAC\u5b9a\u683c\u30d2\u30e5\u30fc\u30ba\u306e\u4f7f\u7528<\/strong><\/td>AC\u30d2\u30e5\u30fc\u30ba\u306fDC\u30a2\u30fc\u30af\u3092\u6d88\u706b\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u305a\u3001\u6301\u7d9a\u7684\u306a\u30a2\u30fc\u30af\u653e\u96fb\u3001\u30d2\u30e5\u30fc\u30ba\u306e\u7834\u65ad\u3001\u706b\u707d\u306e\u5371\u967a\u6027\u304c\u9ad8\u304f\u306a\u308a\u307e\u3059\u3002.<\/td>\u5fc5\u305a\u3001\u76f4\u6d41\u96fb\u5727\u3068\u906e\u65ad\u5b9a\u683c\uff08VDC\u3001gPV\u3001\u30af\u30e9\u30b9 T \u306a\u3069\uff09\u304c\u660e\u8a18\u3055\u308c\u305f\u30d2\u30e5\u30fc\u30ba\u3092\u4f7f\u7528\u3057\u3066\u304f\u3060\u3055\u3044\u3002.<\/td><\/tr>
                                                  \u6e29\u5ea6\u30c7\u30a3\u30ec\u30fc\u30c6\u30a3\u30f3\u30b0\u306e\u7121\u8996<\/strong><\/td>\u9ad8\u6e29\u74b0\u5883\uff08\u4f8b\uff1a\u5c4b\u4e0a\u306e\u30b3\u30f3\u30d0\u30a4\u30ca\u30fc\u30dc\u30c3\u30af\u30b9\uff09\u306b\u3042\u308b\u30d2\u30e5\u30fc\u30ba\u306f\u96fb\u6d41\u5bb9\u91cf\u304c\u4f4e\u4e0b\u3057\u3066\u304a\u308a\u3001\u305d\u308c\u3092\u88dc\u3046\u3088\u3046\u306a\u30b5\u30a4\u30ba\u306b\u3057\u306a\u3044\u3068\u8ff7\u60d1\u306a\u30c8\u30ea\u30c3\u30d7\u3092\u5f15\u304d\u8d77\u3053\u3059\u3002.<\/td>Check the manufacturer’s datasheet for temperature derating curves and adjust your fuse selection accordingly.<\/td><\/tr>
                                                  \u30a2\u30f3\u30c0\u30fc\u30b5\u30a4\u30b8\u30f3\u30b0\u906e\u65ad\u5b9a\u683c (kA)<\/strong><\/td>If a fuse’s interrupting rating is lower than the available fault current, it can explode during a short circuit.<\/td>\u7279\u306b\u30d0\u30c3\u30c6\u30ea\u30fc\u30d0\u30f3\u30af\u306e\u5834\u5408\u3001\u4e88\u60f3\u3055\u308c\u308b\u77ed\u7d61\u96fb\u6d41\u3092\u8a08\u7b97\u3059\u308b\u304b\u63a7\u3048\u3081\u306b\u898b\u7a4d\u3082\u308a\u3001\u3053\u306e\u5024\u3092\u8d85\u3048\u308b\u30d2\u30e5\u30fc\u30ba\u3092\u9078\u629e\u3057\u3066\u304f\u3060\u3055\u3044\u3002.<\/td><\/tr>
                                                  Exceeding the Module’s Max Fuse Rating<\/strong><\/td>Sizing a fuse above the solar panel’s maximum series fuse rating voids the warranty and eliminates protection for the panel itself.<\/td>Always verify your selected fuse rating against the equipment manufacturer’s specifications. Let the lower value dictate your maximum size.<\/td><\/tr>
                                                  \u30d2\u30e5\u30fc\u30ba\u3068\u30ef\u30a4\u30e4\u30fc\u30b2\u30fc\u30b8\u306e\u4e0d\u4e00\u81f4<\/strong><\/td>Installing a fuse with a higher amperage rating than the wire it’s connected to. The wire can overheat and melt before the fuse blows.<\/td>NEC 240.4 \u306b\u5f93\u3044\u3001\u30d2\u30e5\u30fc\u30ba\u306e\u5b9a\u683c\u304c\u5e38\u306b\u4fdd\u8b77\u3059\u308b\u5c0e\u4f53\u306e\u30a2\u30f3\u30da\u30a2\u5bb9\u91cf\u4ee5\u4e0b\u3067\u3042\u308b\u3053\u3068\u3092\u78ba\u8a8d\u3057\u3066\u304f\u3060\u3055\u3044\u3002.<\/td><\/tr>
                                                  \u8aa4\u3063\u305f\u30d2\u30e5\u30fc\u30ba\u901f\u5ea6\u3092\u4f7f\u7528\u3059\u308b<\/strong><\/td>\u654f\u611f\u306a\u96fb\u5b50\u6a5f\u5668\u3092\u4fdd\u8b77\u3059\u308b\u305f\u3081\u306b\u4f4e\u901f\u306e\u6642\u9593\u9045\u5ef6\u578b\u30d2\u30e5\u30fc\u30ba\u3092\u4f7f\u7528\u3059\u308b\u304b\u3001\u307e\u305f\u306f\u7a81\u5165\u96fb\u6d41\u306e\u5927\u304d\u3044\u30e2\u30fc\u30bf\u30fc\u56de\u8def\u306b\u901f\u65ad\u578b\u30d2\u30e5\u30fc\u30ba\u3092\u4f7f\u7528\u3059\u308b\u3002.<\/td>Match the fuse’s time-current curve to the application: gPV for solar, aR for semiconductors, time-delay for motors, etc.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

                                                  \u7d50\u8ad6\u3068\u884c\u52d5\u3078\u306e\u547c\u3073\u304b\u3051<\/h2>\n\n\n\n

                                                  \u6b63\u78ba\u306a DC \u30d2\u30e5\u30fc\u30ba\u306e\u30b5\u30a4\u30b8\u30f3\u30b0\u306f\u30b7\u30b9\u30c6\u30e0\u3067\u3042\u308a\u3001\u5358\u4e00\u306e\u6570\u5024\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002\u305d\u308c\u306f\u3001\u6cd5\u898f\u5236\u306e\u8981\u4ef6\u3001\u74b0\u5883\u306e\u73fe\u5b9f\u3001\u304a\u3088\u3073\u5c0e\u4f53\u304b\u3089\u96fb\u6e90\u305d\u306e\u3082\u306e\u306b\u81f3\u308b\u4e00\u9023\u306e\u5404\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u306b\u7279\u6709\u306e\u4fdd\u8b77\u30cb\u30fc\u30ba\u306e\u30d0\u30e9\u30f3\u30b9\u3092\u53d6\u308b\u305f\u3081\u306e\u4f53\u7cfb\u7684\u306a\u30d7\u30ed\u30bb\u30b9\u3067\u3059\u3002\u592a\u967d\u5149\u767a\u96fb\u306e1.56\u500d\u306e\u500d\u7387\u304b\u3089\u3001\u30d0\u30c3\u30c6\u30ea\u30fc\u306e\u91cd\u8981\u306a\u906e\u65ad\u80fd\u529b\u3001EV\u5145\u96fb\u5668\u306b\u5fc5\u8981\u306a\u30de\u30a4\u30af\u30ed\u79d2\u306e\u5fdc\u7b54\u6642\u9593\u307e\u3067\u3001\u6b63\u3057\u304f\u7406\u89e3\u3059\u308b\u3053\u3068\u304c\u771f\u306e\u96fb\u6c17\u5c02\u9580\u5bb6\u306e\u8a3c\u3067\u3059\u3002\u3053\u308c\u306f\u3001\u5358\u306b\u8a2d\u7f6e\u3055\u308c\u305f\u3060\u3051\u306e\u30b7\u30b9\u30c6\u30e0\u3068\u3001\u4f55\u5341\u5e74\u306b\u3082\u308f\u305f\u3063\u3066\u5b89\u5168\u3067\u4fe1\u983c\u3067\u304d\u308b\u6027\u80fd\u3092\u767a\u63ee\u3059\u308b\u3088\u3046\u306b\u8a2d\u8a08\u3055\u308c\u305f\u30b7\u30b9\u30c6\u30e0\u3068\u306e\u9055\u3044\u3067\u3059\u3002.<\/p>\n\n\n\n

                                                  \u4fe1\u983c\u3067\u304d\u308b\u90e8\u54c1\u3092\u4f7f\u3063\u3066\u3001\u3053\u308c\u3089\u306e\u539f\u5247\u3092\u5b9f\u884c\u3059\u308b\u6e96\u5099\u306f\u3067\u304d\u3066\u3044\u307e\u3059\u304b\uff1f Explore Kuangya’s full range of NEC and IEC-compliant DC fuses<\/strong> \u304a\u5ba2\u69d8\u306e\u30d7\u30ed\u30b8\u30a7\u30af\u30c8\u306b\u5fc5\u8981\u306a\u6b63\u78ba\u306a\u4fdd\u8b77\u3092\u898b\u3064\u3051\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002\u8907\u96d1\u306a\u7528\u9014\u3084\u8a08\u7b97\u306e\u691c\u8a3c\u306b\u3001, \u30a8\u30f3\u30b8\u30cb\u30a2\u30ea\u30f3\u30b0\u30c1\u30fc\u30e0\u3078\u306e\u304a\u554f\u3044\u5408\u308f\u305b<\/strong> \u3042\u306a\u305f\u306e\u6b21\u306e\u30d7\u30ed\u30b8\u30a7\u30af\u30c8\u306b\u5c02\u9580\u5bb6\u306e\u6307\u5c0e\u3092\u3002.<\/p>\n\n\n\n

                                                  \n\n\n\n

                                                  Disclaimer: The information provided in this article is for educational purposes only. Electrical work is dangerous and should only be performed by qualified professionals. Always consult the latest version of the National Electrical Code (NEC), relevant IEC standards, local codes enforced by the Authority Having Jurisdiction (AHJ), and equipment manufacturer’s specifications before designing or installing any electrical system.<\/em><\/p>","protected":false},"excerpt":{"rendered":"

                                                  Introduction: The High Cost of a ‘Close Enough’ Calculation An experienced solar installer, let’s call him Dave, was facing a recurring nightmare. On a 100kW commercial rooftop system he\u2019d completed three months prior, fuses were blowing on perfectly sunny days. The client was losing production, and Dave\u2019s team was wasting time and money on service calls to replace 20A fuses. The initial diagnosis was a bad batch of fuses. But after the third call-out, the real problem became clear. The system was designed with new high-efficiency 550W panels with a short-circuit current (Isc) of 13.9A. Dave’s lead engineer, relying on old habits, had sized the string fuses using a simple […]<\/p>\n","protected":false},"author":4,"featured_media":2359,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[45],"tags":[],"class_list":["post-2358","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-dc-protection-safety"],"blocksy_meta":[],"_links":{"self":[{"href":"https:\/\/cnkuangya.com\/ja\/wp-json\/wp\/v2\/posts\/2358","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cnkuangya.com\/ja\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cnkuangya.com\/ja\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cnkuangya.com\/ja\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/cnkuangya.com\/ja\/wp-json\/wp\/v2\/comments?post=2358"}],"version-history":[{"count":1,"href":"https:\/\/cnkuangya.com\/ja\/wp-json\/wp\/v2\/posts\/2358\/revisions"}],"predecessor-version":[{"id":2362,"href":"https:\/\/cnkuangya.com\/ja\/wp-json\/wp\/v2\/posts\/2358\/revisions\/2362"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/cnkuangya.com\/ja\/wp-json\/wp\/v2\/media\/2359"}],"wp:attachment":[{"href":"https:\/\/cnkuangya.com\/ja\/wp-json\/wp\/v2\/media?parent=2358"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cnkuangya.com\/ja\/wp-json\/wp\/v2\/categories?post=2358"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cnkuangya.com\/ja\/wp-json\/wp\/v2\/tags?post=2358"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}