Terminal blocks are very versatile, so they need to be considered in design. For example, in the electric power industry, the requirements for wiring terminals include: edges and corners of the product shell, hardware burrs, and the connection strength of each component, and even the stability of the product under the conditions of movement.

The protection requirements of terminal shell are mainly JB/T 9568-2000 on the protection level, which is mainly divided into two kinds, one is the protection level of solid foreign matter, the other is the harm caused by water to equipment and products. At the same time about the wiring terminal insulation, often need to consider from the material selection, working voltage and environmental pollution level, determine the electrical clearance and creepage distance, so as to protect the safety of staff and product work.

At the same time also make the product in overvoltage insulation damage; In addition to consider the leakage mark index requirements, the product in the process of use because of the solid insulation material surface under the action of electric field and electrolyte, the formation of conductive path, so that the insulation performance of the shell insulation material decreased, affecting the safety of the product.

　　Also consider the deformation of the material, because the thermoplastic material is mainly on the wiring terminal in the work of the temperature rise and contact resistance, it caused by the high temperature deformation of the shell soft, so that the electrical short circuit, causing serious accidents, so the selection of current-carrying parts of the terminal material is very important.

　　Requirements in the structural design of terminals, operating elements should not be charged, and the internal connection terminals should not be accessible, this is mainly to the reliability of screw torque requirements, should prevent the screw and the accessible terminal, wire accidental loosening and short