[{"data":1,"prerenderedAt":73},["ShallowReactive",2],{"q-fire-107-1-fire-science-031":3},{"subject":4,"subjectSlug":5,"subjectKicker":6,"subjectShort":7,"question":8,"related":27,"sameNumber":52,"hasEssay":26},"火災學概要","fire-science","火災學 · Fire Science","火災學",{"id":9,"webId":10,"year":11,"session":12,"subject":4,"number":13,"stem":14,"options":15,"answer":20,"answerNote":21,"images":22,"imagesPending":23,"lawTimestamp":11,"explanation":24,"explanationDeep":25,"freq":12,"indexable":26},"fire-107-1-火災學概要-031","fire-107-1-fire-science-031",107,1,31,"下列何者並非造成電氣火災的原因？",{"A":16,"B":17,"C":18,"D":19},"短路","斷路","積污導電","半斷線","B",null,[],false,"本題考點：電氣火災的成因分類，重點在辨識哪一種電氣異常會產生足以起火的熱能。\n【正解理由】電氣火災的能量來源，是電流通過異常電阻或異常路徑時產生的焦耳熱與電弧熱，常見型態包括短路、過負載、接觸不良、半斷線、積污導電與漏電。斷路指電路被切斷、電流歸零，既然沒有電流通過就不會有焦耳熱，反而是保護裝置動作後的安全狀態，自然不會是起火原因，故選 B。\n【逐項排除】\n(A) 是原因：短路瞬間電流極大，接點產生高溫電弧與熔珠飛濺，足以引燃被覆與周圍可燃物。\n(B) 非原因：電流中斷即無發熱源，理由如上；考生常與「斷線」「半斷線」字面混淆而誤選。\n(C) 是原因：插頭與插座間長期附著灰塵並吸收濕氣，兩極間產生微小放電使塑膠表面逐步碳化，形成導電路徑後持續電弧而起火。\n(D) 是原因：導線素線部分斷裂後，剩餘導體截面積變小、電阻上升，同樣電流下發熱量倍增，並在反覆彎折處產生間歇電弧。\n【記憶點】會起火的是「電流走不順」,不是「電流走不通」——斷路無電流即無熱。","電氣火災的起火機制可依發熱型態整理成兩大類：一是焦耳熱型，包含過負載、接觸不良與半斷線，共同特徵是電阻異常增大，發熱量正比於電流平方乘電阻，溫度長時間累積後引燃被覆或周圍可燃物；二是電弧型，包含短路、積污導電與部分漏電，特徵是局部瞬間出現數千度高溫，直接點燃絕緣材料並產生熔痕。\n積污導電是本題最值得展開的機制：插座與插頭之間的縫隙長期附著灰塵，吸收空氣中濕氣後在兩極間形成微弱導電通路，反覆微放電使塑膠表面碳化，碳化痕逐漸連成低電阻路徑，最終演變成持續電弧而起火。它的可怕之處在於設備即使未使用、只要插著就可能發生，常見於床頭、電視櫃、神明桌等長期不拔插頭且積塵之處。半斷線則常見於延長線、吹風機與充電線的彎折處，外觀完好而內部素線已斷數股，通電時發熱與間歇電弧同時出現。\n概念對照：短路是相間或相與地之間的低阻抗直接接通，電流暴增；過負載是電流未超過保護裝置動作值卻長期偏高，導線持續升溫；漏電是電流經由非預期路徑流向大地，接地不良時可在接點產生電弧；斷路則是電路開放、電流為零，屬於保護結果而非災因。\n把保護裝置放進來看更清楚：無熔絲開關與保險絲的作用，正是在過負載或短路時主動製造「斷路」,以中斷電流阻止繼續發熱，因此斷路在電氣安全體系裡是結果與對策，不是原因。反過來說，延長線串接、單一插座並用多具高功率電器，使電流長期逼近容許值卻不足以讓保護裝置跳脫，才是過負載型電氣火災最典型的成因。\n延伸考點：火災調查上會以短路痕辨別起火先後——起火前造成的一次痕與受火害後形成的二次痕，金相組織與熔痕形狀不同，是判定電氣是否為起火原因的重要證據；另外電氣火災長年高居建築物火災起火原因前列，也是統計題常出現的素材。",true,[28,32,36,40,44,48],{"webId":29,"stem":30,"number":31,"year":11,"session":12},"fire-107-1-fire-science-030","固體燃料火焰延燒最快的方式為下列何者？",30,{"webId":33,"stem":34,"number":35,"year":11,"session":12},"fire-107-1-fire-science-032","下列何者並非防火區劃構件構造之性質？",32,{"webId":37,"stem":38,"number":39,"year":11,"session":12},"fire-107-1-fire-science-029","下列何者並非學校實驗室火災之特性？",29,{"webId":41,"stem":42,"number":43,"year":11,"session":12},"fire-107-1-fire-science-033","燃燒時若生成的熱與散失的熱保持平衡，燃燒溫度保持均勻之燃燒為下列何者？",33,{"webId":45,"stem":46,"number":47,"year":11,"session":12},"fire-107-1-fire-science-028","下列何者並非古蹟火災防護之特性？",28,{"webId":49,"stem":50,"number":51,"year":11,"session":12},"fire-107-1-fire-science-034","建築物火災發生後，若火勢由局部火災擴散至全面火災之短時間現象稱為？",34,[53,57,61,65,69],{"webId":54,"year":55,"stem":56,"number":13},"fire-113-1-fire-science-031",113,"在電氣火災研究中，木材、電木等絕緣物中，受電氣火花而碳化，碳化部分會逐漸形成微量的結晶，而變成具有導電性，此現象稱為？",{"webId":58,"year":59,"stem":60,"number":13},"fire-112-1-fire-science-031",112,"在長寬高為10×10×4 公尺的密閉空間中以高壓式二氧化碳作為滅火防護設備。若欲將空間中的氧氣濃度降至 15%以下以達到鈍化效果，至少應加入多少立方公尺的二氧化碳？",{"webId":62,"year":63,"stem":64,"number":13},"fire-111-1-fire-science-031",111,"常見消防機關宣導，使用延長線勿將其綑綁，以免引發火災，究其原因為何？",{"webId":66,"year":67,"stem":68,"number":13},"fire-110-1-fire-science-031",110,"有關影響粉塵爆炸的因素，下列何者錯誤？",{"webId":70,"year":71,"stem":72,"number":13},"fire-109-1-fire-science-031",109,"建築物火災在閃燃發生後之全盛期火災的特性，不包括下列何者？",1785129967890]