Explosion proof power maintenance box (IIB, IIC)

Explosion proof power maintenance box (IIB, IIC)Design of the shell

The casing of portable and intrinsically safe instruments and meters is sometimes made of plastic or metal. When selecting a plastic casing, in order to ensure that the plastic casing does not accumulate dangerous static electricity during normal operation, its surface resistance should not exceed 1 × 109 Ω. The plastic casing should undergo impact resistance and thermal stability tests.

Electrical equipment that generates sparks, arcs, or hazardous temperatures during normal operation, as well as Class I electrical equipment with a power greater than 250W or a current greater than 5A, must be electrically connected to the equipment body using a junction box. A junction box is a component that connects cables or wires to electrical equipment. Explosion proof wiring is widely used in Class I explosion-proof electrical equipment. The inner wall of the junction box should be coated with arc resistant paint, and the explosion-proof joint surface on the junction box and main body cavity should be treated with rust prevention, such as applying rust proof oil.

Explosion proof power maintenance box (IIB, IIC)In addition, for explosion-proof electrical appliances, the Ex explosion-proof general sign and MA safety sign should be prominently displayed on their casing.

We have developed the QF40 small explosion-proof starter with a rated voltage of 380V and a rated current of 40A to address the illegal operation of motors in some coal mines underground. The shell design is divided into a main body cavity and a wiring cavity. The shell is made of 3mm thick steel plate. The size and processing accuracy of the explosion-proof joint surface comply with the provisions of GB3836.2. The external dimensions of the shell are 437 mm × 308 mm, and the protection level of the shell is IP54. There is a nameplate located in front of the shell, with the Ex mark and explosion-proof mark d Ⅰ (150 ℃) in the upper right corner of the nameplate. In addition, the nameplate also indicates the name, model, rated voltage, rated current, explosion-proof certificate number, safety mark, factory number, manufacturing date, etc.