Waterproof junction boxes provide moisture-proof, dustproof, or waterproof protection for cable connections in electrical engineering, and are widely used in fire-fighting equipment, steel smelting, petrochemical industry, railway buses, construction sites, mining sites, ship terminals, sewage treatment, and other places. The so-called fixing of the junction box is to connect the junction box with the external wall, upright pole, bracket, machinery and equipment through fastening screws, brackets, hoops, mounting plates, and other accessories, so as to maintain a fixed state for a long time. Due to different shapes, structures, and materials, the external installation and fixation of waterproof junction boxes mainly include the following methods:
1. External direct screw fixation
This fixation method does not require the removal of the upper cover of the junction box during installation. Instead, the exposed mounting holes (usually smooth circular holes) on the base are directly used to fix them to the external wall, bracket, or flat surface of the device using machine screws or self-tapping screws of suitable specifications. Its advantage is that it is more convenient to install and disassemble.
2. Internal screw fixation
Internal screw fixation is the most widely used fixation method for ordinary waterproof junction boxes. This type of junction box usually has mounting holes inside (to better achieve its dustproof and waterproof purposes, usually the mounting holes are designed outside the sealing lip). During installation, it is necessary to first open the upper cover of the junction box, and then use suitable screws to thread through the mounting holes into the external threaded mechanism, This installation method allows the installation screws to be completely built into the junction box (not visible from the outside), taking into account the safety and aesthetics of the wiring equipment to a certain extent.
3. Fix with dedicated installation hardware
Some waterproof junction boxes do not have through holes for external installation at the four corners of their bases, nor do they have protruding bosses to facilitate drilling. However, there are generally 4 to 6 screw holes at the bottom, and they are equipped with special mounting pendants. In this case, the mounting pendant is now fixed to the bottom of the junction box with shorter screws, which forms two to four exposed external mounting points (generally, smaller boxes only need to be installed at two diagonally opposite points, while larger ones require four or more mounting parts). The following fixing methods are the same as the two methods described above.
4. Column support method fixed
In some special applications (such as agricultural irrigation, outdoor lighting, sewage treatment, etc.), it is difficult to effectively fix the junction box in a conventional manner without convenient attachment points. Generally, these applications are underground wiring, which can be achieved by using steel pipe protection at the end of the incoming and outgoing junction box. The outer diameter of the waterproof cable joint protection steel pipe at the inlet and outlet is selected, and the protective steel pipe is locked by the forcing nut of the cable joint, Then, the entire steel pipe and junction box are erected, and the lower end is poured with concrete. This type of protective steel pipe not only serves as a wire protector, but also forms a support for the junction box. In the application of the junction box as a control terminal, this is a highly recommended fixing method.