The hole for a distribution box should be about 20 mm larger than the box's length and width, with a depth equal to the box thickness plus the plastering thickness of the wall.

Detailed Guidelines

Length and Width: When embedding a distribution box in a wall, the reserved hole should be approximately 20 mm larger than the box's dimensions in both length and width. This extra space allows for easier installation, adjustment, and alignment of the box within the wall cavity . Depth: The depth of the hole should be the thickness of the distribution box plus the plastering thickness of the inner wall. This ensures that the box sits flush with the finished wall surface and allows for proper plastering around the edges . Fixing the Box: For masonry walls, the box can be secured by filling concrete between the box and the wall. For smaller boxes, wood bricks can be embedded at the installation site, and the box can be fixed with wood screws . The box should be installed firmly, horizontally, and vertically, with a vertical deviation not exceeding 3 mm . Additional Considerations:

• Ensure there is no gap around the box in concealed installations, and coat contact parts with anti-corrosion paint .
• Leave enough space around the box for ventilation and future maintenance .
• The hole size may also need to accommodate internal components such as circuit breakers, busbars, and wiring space, especially in larger or industrial distribution boxes . By following these guidelines, the distribution box will be securely embedded, properly aligned, and accessible for maintenance while maintaining safety and compliance with standard installation practices.