电气项目里，桥架常被归到“辅材”里压价，真到验收阶段，锈蚀、塌腰、接地不通，返工成本比省下的差价高得多。

In electrical projects, cable trays are often classified as "auxiliary materials" to lower their prices. However, during the acceptance stage, corrosion, collapse, and grounding issues occur, resulting in much higher rework costs than the saved price difference.

先按环境定材质，不按颜色比价：

First determine the material based on the environment, do not compare prices based on color:

室内干燥办公区：电镀锌或喷塑，够用且经济；

Indoor dry office area: galvanized or spray painted, sufficient and economical;

地下室、车库、管廊：热浸锌，锌层按工况留余量；

Basement, garage, and pipe gallery: hot-dip galvanized, with excess zinc layer left according to working conditions;

厂房动力主干：梯级式或加强托盘，散热好、检修方便；

Power backbone of the factory: stepped or reinforced tray, good heat dissipation, easy maintenance;

弱电机房：槽式封闭，防干扰；

Weak current computer room: enclosed in a trough, anti-interference;

化工、沿海、高湿车间：锌铝镁、304/316L不锈钢或玻璃钢。

Chemical, coastal, high humidity workshops: Zinc aluminum magnesium, 304/316L stainless steel or fiberglass.

板厚跟着宽度和跨距走。常规参考：宽300mm内底板≥1.2mm，300–600mm≥1.5mm，大跨距或重载继续加厚。合同里写“实测厚”，到货带卡尺抽检，防标厚货薄。

The thickness of the board follows the width and span. Conventional reference: Bottom plate with a width of 300mm ≥ 1.2mm, 300-600mm ≥ 1.5mm, and further thickening for large spans or heavy loads. The contract states' measured thickness', and upon arrival, a caliper will be used for sampling to prevent excessive thickness.

安装端几条硬指标：

Several hard indicators for installation:

支吊架水平间距按荷载算，弯通、三通、端部0.3–0.5m内加密；

The horizontal spacing between supports and hangers is calculated based on the load, and it is increased within 0.3-0.5m for bends, tees, and ends;

钢制直线段每30m设伸缩节，过变形缝加补偿，螺栓留热胀余量；

Expansion joints shall be installed every 30m in the steel straight section, and compensation shall be added for deformation joints. Bolts shall have thermal expansion allowance;

金属桥架全长至少2处接PE干线，超30m每20–30m补点，镀锌连接端每端≥2颗防松螺栓；

At least 2 locations along the entire length of the metal bridge shall be connected to the PE main line. For distances exceeding 30m, additional points shall be added every 20-30m. At least 2 anti loosening bolts shall be installed at each end of the galvanized connection end;

动力填充率≤40%，控制电缆≤50%，留两成扩容；

Power filling rate ≤ 40%, control cable ≤ 50%, leaving 20% for expansion;

消防回路用防火槽盒，要对应耐火时限的检测报告，别用普通喷塑顶替。

Fire resistant trough boxes for fire protection circuits should have corresponding fire resistance test reports, and should not be replaced with ordinary spray paint.

采购前让厂家出荷载表、跨距挠度值和镀层检测记录，比只看“国标”两个字靠谱。

Before purchasing, ask the manufacturer to provide a load table, span deflection values, and coating inspection records, which is more reliable than just looking at the two words' national standard '.

桥架是电缆系统的承重骨架，先算荷载和环境，再定板厚与防腐，后期才少返工。

The cable tray is the load-bearing skeleton of the cable system. The load and environment are calculated first, and then the plate thickness and anti-corrosion are determined to reduce rework in the later stage.