The fiber optic splice closure is a passive device that ensures the secure connection of the optical cable. It is divided into overhead, pipeline, and direct burial in the occasion of application; the internal connection method is divided into straight connection and non-sequential connection. The former is in short Two optical cables with the same number of cores are connected together. The latter is a method for separating one large number of optical fiber cables and one or more small number of optical cables corresponding to each other or multiple optical cables to interpenetrate each other. The backbone network usually uses The direct method is the main method, and the access layer is based on different methods; the connection between optical fibers is divided into mechanical and thermal contraction. The former selects the mechanical connector to mechanically break the optical fiber that requires docking and passes the concentricity of the connector. The cores are aligned, and the latter is selected by a fusion splicer to heat-bond together the fibers that are required to be connected and fixed and maintained by heat-shrinkable sleeves. Because the latter has little additional attenuation and has little impact on the entire network, most of the current use of thermal contraction is to improve the communication capabilities of the network. Currently, fiber optic splice closure are mainly divided into plastic housings and stainless steel housings. The plastic housings are the main components. The plastics used are usually those with excellent functions in engineering plastics. Polycarbonate and alloy PP are commonly used. Polycarbonate can be said to be the best in current engineering plastics, and its excellent high and low temperature function can be used in various harsh environments. The poor waterproof performance of the DOME Fiber Closure is due to the weather, and the water in the fiber optic splice closure is short-circuited, which can easily cause a large-scale power outage. The fiber optic splice closure is easy to enter the water because the space inside the fiber optic splice closure is small, and the 35mm2 cable power supply line is fixed with a plastic expansion pipe, so there is no room for waterproof bends, and even rain flows along the cable to the live terminal. On the other hand, due to the small gap between the terminals, the insulation measures are not in place, and they are easily short-circuited after entering the water.