电缆桥架是电气光缆裸露在外的部分，虽然线路外部有绝缘层防护，但是由于电气光缆均是导电线路，因此必须接地形成一个完好的电气连通才算可靠。而金属电缆桥架在生产时没有做出的接地螺栓，因此在施工的时候只能利用其连接板上的螺栓来连接固定跨接接地线。电缆桥架及其连接板涂有防腐涂层，若跨接连接处的绝缘防腐涂层不干净，将不能形成良好的电气连接，其接触电阻不能满足要求，将会影响到电缆桥架跨接接地线的可靠连接和接地质量。

　　Cable tray is the exposed part of electrical optical cable. Although there is insulation layer protection on the outside of the line, since electrical optical cable is a conductive line, it must be grounded to form a complete electrical connection for safety and reliability. However, the metal cable tray did not have professional grounding bolts during production, so during construction, only the bolts on its connecting plate can be used to connect and fix the grounding wire. The cable tray and its connecting plate are coated with anti-corrosion coating. If the insulation anti-corrosion coating at the cross connection is not removed completely, a good electrical connection cannot be formed, and the contact resistance cannot meet the requirements, which will affect the reliable connection and grounding quality of the cable tray's cross grounding wire.

　　《验收规范》规定：电缆桥架及其支架接地连接可靠，其全长应不少于2处与接地（PE）干线相连接；非镀锌电缆桥架间连接板的两端跨按铜芯接地线，其小允许截面应不小于4平方毫米；镀锌电缆桥架间连接板的两端可不跨接接地线，但连接板两端应不少于2个有防松螺帽或防松垫圈的螺栓连接固定。这是在接地施工时的要求，目前大多数施工人员都是依据这个标准进行施工操作。但是熟悉工程的人都知道，只按照限度来接地操作是完全不够的，在具体施工中依旧存在很多接地问题：

　　According to the "Acceptance Specification", the grounding connection of cable trays and their supports should be reliable, and their total length should be connected to the grounding (PE) main line at no less than 2 points; The two ends of the connecting plate between non galvanized cable trays should be crossed with copper core grounding wires, and the minimum allowable cross-section should not be less than 4 square millimeters; The two ends of the connecting plate between galvanized cable trays may not be connected to the grounding wire, but the two ends of the connecting plate should be fixed with at least 2 bolts with anti loosening nuts or anti loosening washers. This is the minimum requirement for grounding construction, and currently most construction personnel follow this standard for construction operations. However, those familiar with engineering know that only following the minimum grounding operation is not enough, and there are still many grounding problems in specific construction:

　　（1）电缆桥架全长不大于30m的，应有不少于2处与接地干线相连接，但施工中往往只做到1处与接地干线相连接，其末端应与接地干线相连接的要求常常被忽视；全长大于30m的，由于设计未注明电缆桥架与接地干线相连接的施工要求和具体连接位置，施工中通常多2处与接地干线相连接，未能做到每隔20~30m增加1处与接地干线相连接。

　　(1) For cable trays with a total length of no more than 30m, there should be no less than 2 connections to the grounding main line. However, during construction, only 1 connection to the grounding main line is often achieved, and the requirement that the end should be connected to the grounding main line is often overlooked; For cables with a total length greater than 30m, due to the lack of construction requirements and specific connection locations for cable trays to be connected to the grounding main line in the design, there are usually no more than 2 connections to the grounding main line during construction, and it is not possible to add 1 connection to the grounding main line every 20-30 meters.

　　（2）电缆桥架跨接接地线截面由于设计不明确，施工中往往只按规范规定的小允许截面4平方毫米（铜质质选择，使其截面可能不满足要求，存在接地隐患。

　　(2) Due to unclear design, the cross section of the grounding wire for cable trays is often only allowed to be 4 square millimeters according to the minimum allowable section specified in the specifications during construction (copper material selection may not meet the requirements, which poses a grounding safety hazard).

　　（3）对于非镀锌电缆桥架，不少产品本体上没有设置专用的接地螺栓，在施工中，往往利用连接板的螺栓，在连接板处对跨接接地线进行连接固定。由于连接板涂有绝缘的防腐涂层，可能使跨接接地线与电缆桥架的金属本体之间不能形成可靠的电气连通，而此时跨接地线连接又是申接连接，当出现连接板松动、脱开等现象时，将会造成跨接接地线连接不牢，甚断开，使得电缆桥架失去接地，存在接地隐患。

　　(3) For non galvanized cable trays, many products do not have dedicated grounding bolts installed on the body. During construction, the bolts of the connecting plate are often used to connect and fix the grounding wire at the connecting plate. Due to the insulation anti-corrosion coating on the connecting plate, reliable electrical connection may not be formed between the cross grounding wire and the metal body of the cable tray. At this time, the cross grounding wire connection is also a nominal connection. When the connecting plate is loose or disconnected, it will cause the cross grounding wire connection to be weak or even disconnected, resulting in the loss of grounding of the cable tray and posing a grounding safety hazard.

　　（4）电缆桥架的支架接地在施工中漏接现象较为普遍，而电缆桥架与支架之间也没有连接固定，使得支架没有可靠接地。介于上述原因，在施工时必须采取以下措施来确保电缆桥架接地：

　　(4) The grounding of cable tray supports is commonly missed during construction, and there is no connection or fixation between cable trays and supports, resulting in unreliable grounding of the supports. Due to the above reasons, the following measures must be taken during construction to ensure the safe grounding of cable trays:

　　（1）熟悉施工设计文件中关于接地干线设置、连接位置，以及接地干线截面、跨接接地线截面选择等内容。

　　(1) Familiar with the construction design documents regarding the setting and connection positions of grounding main lines, as well as the selection of grounding main line sections and cross grounding wire sections.

　　（2）接地点可在电气预埋阶段预留引出，以满足电缆桥架的始端、末端及中间部位的接地要求。接地干线材质、截面应符合设计要求。当设计未作要求时，可参照《验收规范》中保护导体（PE线导体）截面的规定选择截面。当接地干线采用型钢（如扁钢或圆钢），其截面应符合设计要求或按相应电导值进行换算。

　　(2) The grounding point can be reserved during the electrical pre embedding stage to meet the grounding requirements of the starting, ending, and middle parts of the cable tray. The material and cross-section of the grounding main line should meet the design requirements. When there are no requirements in the design, the cross-section of the protective conductor (PE wire conductor) can be selected according to the provisions of the "Acceptance Specification". When the grounding main line is made of steel (such as flat steel or round steel), its cross-section should meet the design requirements or be converted according to the corresponding conductivity value.

　　（3）跨接接地线应采用铜芯软导线或镀锡铜编织线，不应采用单股铜芯导线，其截面应符合设计要求。当设计未作要求时，跨接线允许截面应不小于4平方毫米（铜质）、不大于25平方毫米（铜质）。

　　(3) The jumper grounding wire should use copper core flexible wire or tinned copper braided wire, and should not use single stranded copper core wire. Its cross-section should meet the design requirements. When not specified in the design, the allowable cross-sectional area of the jumper wire should be no less than 4 square millimeters (copper) and no more than 25 square millimeters (copper).

　　（4）跨接接地宜采用焊接在电缆桥架本体上的专用接地螺栓作为跨接接地线连接点，不宜采用连接板连接螺栓作为跨接接地线的连接点；若产品未带有专用接地螺栓，而施工中用连接板的螺栓进行跨接接地连接时，应将跨接接地连接处的不导电涂层进行处理，以保证跨接接地线的可靠电气连通。

　　(4) Special grounding bolts welded to the cable tray body should be used as the connection point for the grounding wire, and connection plate connection bolts should not be used as the connection point for the grounding wire; If the product does not come with a dedicated grounding bolt and the bolts of the connecting plate are used for cross grounding connection during construction, the non-conductive coating at the cross grounding connection should be treated to ensure reliable electrical connection of the cross grounding wire.

　　（5）跨接接地可采用每节电缆桥架之间的跨接接地线进行跨接连接，也可采用沿电缆桥架全长敷设一根铜排或铜芯导线或镀锌型钢（扁钢或圆钢）作为接地干线，每节（包括直通、弯通等等电缆桥架应少有1处与其进行可靠连接。连接处的连接螺栓应配置弹簧垫圈，保证连接紧固可靠。

　　(5) Cross grounding can be achieved by using the grounding wire between each section of the cable tray for cross connection, or by laying a copper bar or copper core wire or galvanized steel (flat steel or round steel) along the entire length of the cable tray as the grounding main line. Each section (including straight through, bent through, etc.) of the cable tray should have at least one reliable connection with it. The connecting bolts at the connection should be equipped with spring washers to ensure a tight and reliable connection.

　　（6）对于镀锌电缆桥架可利用其镀锌的连接板进行跨接，而不必采用跨接线进行跨接，但连接板的两端应不少于2个有防松螺帽或防松垫圈的螺栓进行连接固定，避免出现连接松动、脱开等现象，保证跨接接地的可靠连接。

　　(6) For galvanized cable trays, their galvanized connecting plates can be used for bridging without the need for jumper wires. However, the two ends of the connecting plate should be fixed with at least two bolts with anti loosening nuts or washers to avoid loose or disconnected connections and ensure reliable grounding.

　　（7）支、托、吊架应与电缆桥架可靠连接并接地，可与沿电缆桥架全长敷设的一根铜排或铜芯导线或镀锌扁钢作为PE线的接地线相连接，也可与已有接地电缆桥架进行跨接连接，如可用铜芯软导线或镀锡铜编织线进行跨接连接，或不少于2处用爪型螺母与电缆桥架进行连按固定，使其与电缆桥架形成可靠的电气连通。建筑电气设计和施工中，电缆桥架是要做接地的，这点是比较明确的，但是电缆桥架的支架是否也要做接地呢？我们来看下规范是怎么要求的，依据国标GB50169-2016《电气装置安装工程接地装置施工及验收规范》

　　(7) Supports, brackets, and hangers should be reliably connected to cable trays and grounded. They can be connected to a copper busbar, copper core wire, or galvanized flat steel as a PE wire laid along the entire length of the cable tray, or they can be cross connected to existing grounded cable trays. For example, copper core flexible wires or tinned copper braided wires can be used for cross connection, or at least two claw nuts can be used to connect and fix the cable tray, forming a reliable electrical connection with the cable tray. In the design and construction of building electrical systems, it is quite clear that cable trays need to be grounded. However, should the supports of cable trays also be grounded? Firstly, let's take a look at what the specifications require, based on the national standard GB50169-2016 "Code for Construction and Acceptance of Grounding Devices in Electrical Equipment Installation Engineering"

　　3.0.4条要求，电缆桥架、支架和井架必须接地。从以上规范条文看，似乎电缆桥架的支架也要做接地，其实不然，我们先了解一下电缆桥架为什么要做接地。我们所说的电缆桥架接地，更明确一点是指电缆桥架与保护导体相连接，其目的是在桥架内部的电缆发生绝缘破损而使相线与桥架接触时（发生单相接地故障），接地故障电流能通过保护导体（PE线）返回变压器的中性点，使得发生绝缘破损的电缆回路的保护电器能及时切除该接地故障，从而隐患，所以电缆桥架需要做接地。

　　Requirement 3.0.4: Cable trays, brackets, and derricks must be grounded. From the above specifications, it seems that the brackets of cable trays also need to be grounded. However, this is not the case. Let's first understand why cable trays need to be grounded. The cable tray grounding we refer to more specifically refers to the connection between the cable tray and the protective conductor. Its purpose is to enable the grounding fault current to return to the neutral point of the transformer through the protective conductor (PE line) when the insulation damage occurs in the cable tray and the phase line comes into contact with the tray (single-phase grounding fault), so that the protective electrical appliances of the cable circuit with insulation damage can timely cut off the grounding fault and eliminate safety hazards. Therefore, the cable tray needs to be grounded.

　　电缆桥架作为电缆敷设的直接载体，是与电缆直接接触的，所以会发生以上接地故障的可能，然而电缆桥架的支架并未与电缆直接接触，也就不存在电缆绝缘破损而导致相线与电缆桥架支架直接接触而产生的接地故障，因此电缆桥架支架的接地与否并未对电缆因绝缘破损产生的故障有什么影响。从T/CECS31-2017 《钢制电缆桥架工程技术规范》对桥架的定义如下：电缆桥架：由主体（托盘或梯架）、附件和支、吊架等部件构成，用于支承电缆线路且有一定刚度的结构系统。

　　As a direct carrier for cable laying, cable tray is in direct contact with the cable, so there is a possibility of grounding faults mentioned above. However, the support of the cable tray is not in direct contact with the cable, so there is no grounding fault caused by direct contact between the phase line and the cable tray support due to cable insulation damage. Therefore, the grounding of the cable tray support does not have any impact on the faults caused by cable insulation damage. The definition of cable tray in T/CECS31-2017 "Technical Specification for Steel Cable Tray Engineering" is as follows: Cable tray: a structural system composed of main body (tray or ladder), accessories, supports, hangers and other components, used to support cable lines and has a certain degree of rigidity.

　　由以上定义可知，电缆桥架已经包括其安装支架等附件，所以GB50169-2016《电气装置安装工程接地装置施工及验收规范》

　　From the above definition, it can be seen that cable trays already include their installation brackets and other accessories. Therefore, GB50169-2016 "Code for Construction and Acceptance of Grounding Devices in Electrical Equipment Installation Engineering"

　　3.0.4条所写的支架并不是指电缆桥架的支架，而应该是指与电缆直接有接触的（与电缆井架一样）用于直接敷设电缆的电缆支架。由此可知，在电缆桥架的支架没有与电缆直接接触的情况下，电缆桥架的支架是可以不用做保护接地的。

　　The bracket mentioned in Article 3.0.4 does not refer to the bracket of the cable tray, but rather to the cable bracket that comes into direct contact with the cable (similar to the cable rack) and is used for directly laying cables. It can be inferred that in the absence of direct contact between the bracket of the cable tray and the cable, the bracket of the cable tray does not need to be protected by grounding.

　　2、火警探测器可以采用联网供电的独立式的，也可以是区域报警系统、集中报警系统等。

　　2. Fire detectors can be independent and powered by a network, or they can be regional alarm systems, centralized alarm systems, etc.

　　本文由  山东电缆桥架 友情奉献.更多有关的知识请点击  http://www.sddlqj.cn/   真诚的态度.为您提供为的服务.更多有关的知识我们将会陆续向大家奉献.敬请期待.

　　This article is a friendly contribution from Shandong Cable Bridge For more related knowledge, please click http://www.sddlqj.cn/ Sincere attitude To provide you with comprehensive services We will gradually contribute more relevant knowledge to everyone Coming soon.