Cable tray cable is easy to catch fire. Why? Some of the materials used in the cable are flammable. When the ignition and combustion of local cable reaches high temperature, it will melt. When the ignition temperature exceeds the adjacent cable, it will cause the cable to burn for a long time. This problem is very serious, not only damaging the bridge, but also endangering the safety of people. In order to solve the fire problem, we need to know what causes the bridge cable to catch fire. Therefore, the following are some reasons for the fire of Jinan cable bridge.

　　1. 電纜電流設(shè)計不當(dāng)

　　1. Improper design of cable current

　　電纜負(fù)荷選擇不當(dāng)，部分電纜長期滿載或經(jīng)常超負(fù)荷運行，導(dǎo)致電纜溝、隧道溫度升高、電纜老化、受潮、過熱等短路自燃。

　　Improper selection of cable load, long-term full load or frequent overload operation of some cables, resulting in temperature rise of cable trench and tunnel, cable aging, damp, overheating and other short-circuit spontaneous combustion.

　　2. 電纜安裝和施工不當(dāng)

　　2. Improper cable installation and construction

　　在電纜橋架施工中，有的機(jī)組沒有采取防火措施，電纜敷設(shè)混用，經(jīng)常會產(chǎn)生有毒煙霧，將中低壓電纜和高壓電纜敷設(shè)在一起;在鋪設(shè)電纜時，部分施工人員沒有嚴(yán)格遵守操作規(guī)程和技術(shù)要求，經(jīng)常因刮擦、碰撞、壓力、扭轉(zhuǎn)等原因造成電纜外層損壞。水易受濕氣影響，運行過程中保溫層損壞，引起電弧和火災(zāi)。

　　In the construction of cable bridge, some units have not taken fire prevention measures, and the cable laying is mixed, which often produces toxic smoke, laying the medium and low voltage cables together with the high voltage cables; when laying the cables, some construction personnel fail to strictly abide by the operating procedures and technical requirements, and often damage the outer layer of the cables due to scratch, collision, pressure, torsion and other reasons. Water is easy to be affected by moisture, and the insulation layer is damaged during operation, causing arc and fire.

　　3.電線電纜故障

　　3. Wire and cable failure

　　電線電纜的故障有以下幾種:(1)電纜橋架電纜生產(chǎn)粗糙，保溫層受潮，導(dǎo)致電纜頭和端子盒在運行中失效和自燃、爆炸;

　　The faults of wires and cables are as follows: (1) the production of cable bridge and cable is rough, and the insulation layer is damp, which leads to the failure, spontaneous combustion and explosion of cable head and terminal box in operation;

　　(2)有些電纜技師操作不嚴(yán)格，不注意衛(wèi)生，雜質(zhì)、污物清洗不干凈，造成接口接觸不良;

　　(2) Some cable technicians operate not strictly, do not pay attention to sanitation, impurities, dirt cleaning is not clean, resulting in poor interface contact;

　　接頭工藝不精細(xì)，生產(chǎn)質(zhì)量不高，防火措施少，在發(fā)生故障時受高壓、大電流沖擊造成接頭起火;

　　The joint process is not fine, the production quality is not high, and the fire prevention measures are few. The joint fires due to the impact of high voltage and large current in case of failure;

　　(4)接地電纜不良，地線焊接不牢固，接觸不良，電阻值過大，導(dǎo)致電纜接地故障電流比正常短路電流小，使電流保護(hù)器不能及時切斷故障，并出現(xiàn)電弧、火花。

　　(4) The grounding cable is poor, the ground wire is not welded firmly, the contact is poor, and the resistance value is too large, which causes the cable grounding fault current to be smaller than the normal short-circuit current, so that the current protector cannot cut off the fault in time, and there are arcs and sparks.

　　讓我們總結(jié)一下原因引起的濟(jì)南電纜橋架主要是電線電纜過載,短路,過多的接觸電阻和外部熱源作用,在短路,局部過熱等故障狀態(tài)和外部加熱作用,絕緣材料電阻下降,失去絕緣能力甚燃燒,然后引起火災(zāi)。因此，在施工過程中必須考慮火災(zāi)因素。做好防火措施和應(yīng)急準(zhǔn)備是非常重要的。

　　Let's summarize the main causes of Jinan cable bridge are wire and cable overload, short circuit, excessive contact resistance and external heat source effect. In short circuit, local overheating and other fault states and external heating effect, the resistance of insulation material decreases, loss of insulation capacity or even burning, and then fire. Therefore, fire factors must be considered in the construction process. It is very important to do well in fire prevention measures and emergency preparedness.