Installation elements of panel electrical box

5. **Line connection**: For the spiral fuse installed in the waterproof electrical box, the power wire should be connected to the terminal of the middle contact, and the load wire should be connected to the threaded terminal. The resistance value of the feeder line between lines and line-to-ground of the box line is greater than 0.5M ohm, and the resistance value of the secondary line is greater than 1M ohm; the operating current of the leakage protection device is not greater than 30mA, and the action time is not greater than 0.1S.

6. **Exposed electrical box**: If the exposed electrical box is designed in the living room and installed on the wall, it should be fixed with open-foot bolts (expansion bolts). The length of the bolts is generally the buried depth (75 ~150mm), the thickness of the box bottom plate, the sum of the thickness of nuts and washers, plus 5mm.