桥架采购非常容易被单价带偏——尤其山东这类厂房、车站、电厂项目多，跨度一长，薄板硬拉成6米节，上缆就变“彩虹桥”。

The procurement of cable trays is most easily biased by unit prices, especially for projects such as factories, stations, and power plants in Shandong. With a long span, if the thin plate is pulled into 6-meter sections, the cable will become a "rainbow bridge".

一、结构按电缆类型定，别乱换

1、 The structure should be determined according to the cable type, do not replace randomly

大截面动力缆、高压主干：优先梯式，开放结构散热好，额定荷载下跨距可做3–6米，加强型能到6–8米；

Large section power cable and high-voltage backbone: priority ladder type, open structure with good heat dissipation, can achieve a span of 3-6 meters under rated load, and reinforced type can reach 6-8 meters;

动力+控制混敷：托盘式，底板开孔30%–50%，既托细线又留散热；

Hybrid application of power and control: tray type, with a bottom plate opening of 30% -50%, which not only supports fine wires but also allows for heat dissipation;

弱电机房、医院敏感回路：槽式全封闭，但满填要按15%–30%做载流量降容，别拿来走大动力主馈线。

Weak current machine room, hospital sensitive circuit: fully enclosed trough type, but full filling should be reduced by 15% -30% of current carrying capacity, do not take it to the main power feeder.

二、大跨距不是“加厚板材”这么简单

2、 Large span is not as simple as "thick plate"

6–8米、每米荷载≤50kg，梯边加加强筋性价比非常高；超8米或密集高压缆，得配中间托臂，必要时加强筋+中间支撑双保险。订货写清「额定均布荷载+跨距」，挠度按≤L/200校核，别只报宽高。

6-8 meters, with a load of ≤ 50kg per meter, the most cost-effective option is to add reinforcing bars at the edge of the ladder; For high-voltage cables exceeding 8 meters or densely packed, a middle support arm is required, and if necessary, reinforcement bars and middle support double safety should be added. Order clearly stating 'rated uniformly distributed load+span', with deflection verified as ≤ L/200, do not only report width and height.

三、防腐跟着环境走，不一刀切

3、 Corrosion prevention follows the environment, not a one size fits all approach

普通室内车库用热浸锌（锌层≥65μm）；化工厂、沿海、污水区直接上玻璃钢或316L不锈钢，冷镀喷漆两年起皮；户外托臂同样要热镀锌，切割端面48小时内补富锌漆。

Hot dip galvanizing for ordinary indoor garages (zinc layer ≥ 65 μ m); Chemical plants, coastal areas, and sewage areas are directly coated with fiberglass or 316L stainless steel, and cold plated and painted for two years before peeling; Outdoor support arms should also be hot-dip galvanized, and the cut end face should be coated with zinc rich paint within 48 hours.

四、安装验收三条红线

4、 Three red lines for installation acceptance

支吊架：水平≤2米、转弯两侧500mm内加支架，垂直段≤1.5–2米；

Support and hanger: Horizontal ≤ 2 meters, support added within 500mm on both sides of the turn, vertical section ≤ 1.5-2 meters;

接地：镀锌桥架连接板每端≥2颗防松螺栓，非镀锌建议跨≥4mm²铜线，全长＞30米每20–30米补接地点；

Grounding: Each end of the galvanized bridge connecting plate must have at least 2 anti loosening bolts. Non galvanized cables must span over copper wires of ≥ 4mm ², and grounding points must be added every 20-30 meters for a total length greater than 30 meters;

防火封堵：穿墙穿楼板用防火包+防火泥，厚度≥楼板厚，水泥糊弄不过消防。

Fireproof sealing: When passing through walls and floors, use fireproof bags and fireproof mud with a thickness ≥ the thickness of the floor slab. Cement paste cannot withstand fire protection.

桥架本身是半成品，选型算荷载、安装卡支架、验收盯接地和封堵——这三关过了，后期才不会趴管廊上返工。

The cable tray itself is a semi-finished product. After selecting and calculating the load, installing the card bracket, inspecting and grounding, and sealing - these three aspects have been passed, and there will be no rework on the pipe gallery in the later stage.