机电安装里有个怪现象：桥架横平竖直、支架间距全绿、电缆也放得整整齐齐，结果消防验收和电气验收分开查，一张整改单打回来——“穿越防火分区未封堵、金属桥架接地不连续”。

There is a strange phenomenon in the mechanical and electrical installation: the bridge frame is horizontal and vertical, the support spacing is all green, and the cables are neatly arranged. As a result, the fire inspection and electrical inspection are checked separately, and a rectification sheet is returned - "passing through the fire compartment is not blocked, and the grounding of the metal bridge frame is discontinuous".

这两件事和桥架本身好不好没关系，全是“收尾巴”的活，但漏一项整段线路都得拆吊顶。

These two things have nothing to do with whether the cable tray itself is good or not. It's all a "tail closing" job, but if one item is missed, the entire section of the line will have to remove the ceiling.

先说接地，别以为“镀锌桥架自带锌层”就等于接地了。

Let's talk about grounding first. Don't think that 'galvanized bridge with zinc layer' is equivalent to grounding.

镀锌桥架每段连接板两端至少2颗带弹簧垫圈或防松螺母的螺栓，把表面漆层和氧化皮在接触点磨掉再拧紧，整条桥架才导通。

At least 2 bolts with spring washers or anti loosening nuts shall be installed at both ends of each connecting plate of the galvanized bridge. The surface paint layer and oxide skin shall be ground off at the contact point and then tightened, and the entire bridge shall be conductive.

非镀锌、喷塑、不锈钢桥架，连接板两端建议跨接不小于4mm²的铜编织带，一端一颗螺栓别省。

Non galvanized, spray painted, stainless steel cable trays must have copper braided strips of no less than 4mm ² bridged at both ends of the connecting plate, with one bolt omitted at one end.

全长至少两处和接地干线接通；超过30米每隔20到30米补一点。用毫欧表抽测任意两点，导通电阻别超过0.05Ω，不然雷击或漏电时整条架子带电。

At least two points along the entire length should be connected to the grounding main line; Add a little every 20 to 30 meters if it exceeds 30 meters. Use a milliohmmeter to measure any two points, and ensure that the conductivity does not exceed 0.05 Ω, otherwise the entire frame will be charged when struck by lightning or leakage.

非常容易被忽略：桥架进出配电柜那一段，很多人只接柜体没接桥架，结果柜门一开，桥架悬空不接地。

The most easily overlooked part is the section where the cable tray enters and exits the distribution cabinet. Many people only connect the cabinet without connecting the cable tray, resulting in the cabinet door opening and the cable tray hanging in the air without grounding.

再说穿墙、穿楼板、进竖井这三个位置：

Let's talk about the three positions of passing through walls, passing through floors, and entering vertical shafts:

桥架穿过防火墙或楼板，洞和桥架外缘之间的缝，建议用防火包打底+防火泥压面+防火板封边，厚度不小于墙或楼板本身。别拿水泥砂浆糊，遇火一炸裂，烟火顺着空腔跑到上一层。

When the bridge passes through the firewall or floor slab, the gap between the hole and the outer edge of the bridge slab must be covered with fireproof wrapping, fireproof mud pressure surface, and fireproof board edge sealing, with a thickness not less than the wall or floor slab itself. Don't use cement mortar paste, it will explode when exposed to fire, and fireworks will run down the cavity to the next layer.

同一处多根桥架并列穿墙，每根单独封堵，不能几根管子包在一大坨泥里——后期换一根都得全砸。

Multiple cable trays are connected in parallel through the wall at the same location, with each one sealed separately. Several pipes cannot be wrapped in a large pile of mud - if you replace one later, you will have to smash it all.

户外桥架进室内墙体，室内侧要高于室外侧，防止雨水顺着槽底倒灌进机房。

The outdoor bridge should enter the indoor wall, and the indoor side should be higher than the outdoor side to prevent rainwater from flowing into the machine room through the bottom of the trough.

两个现场红线：

Two on-site red lines:

隐蔽工程封闭前拍照留底。吊顶一封，再想补接地跨接线就要拆板，人工比材料贵十倍。

Take photos and keep records before the closure of concealed works. Once the ceiling is sealed, if you want to repair the grounding jumper wire, you need to remove the board, which is ten times more expensive than materials in terms of labor.

伸缩节别装在墙体内。钢制直线段超过30米、铝合金超过15米才设伸缩节，位置放在可视检修区，穿变形缝处单独做补偿，不要和防火封堵挤在同一个洞里。

Do not install expansion joints inside the wall. Expansion joints should only be installed if the steel straight section exceeds 30 meters or the aluminum alloy exceeds 15 meters. They should be placed in the visible maintenance area and compensated separately at the deformation joint. They should not be squeezed in the same hole as the fireproof sealing.

把“连接点磨光拧紧、非镀锌必跨铜线、穿墙三明治封堵、隐蔽前拍照”这四句钉在施工班组的班前会，验收时这两栏基本一次过，不用等整改通知。

Nail the four sentences of "polished and tightened connection points, non galvanized copper wire must be crossed, wall sandwich sealing, and taking photos before concealment" to the pre shift meeting of the construction team. During the acceptance inspection, these two columns are basically passed at once without waiting for the rectification notice.