The most common screw size for electrical boxes is #6-32, which is suitable for standard outlet boxes and switch boxes. However, for heavier applications, such as ceiling fans or light fixtures, you may need to use a larger screw size like #8-32 or #10-32. They are one-pole modular units with an interlocking dovetail feature that enables ganging of the blocks to create multi-pole configurations according to application requirements. Distribution box screw specifications are generally M3, M4, M5, M6, M8, etc. They are typically made of metal or plastic and have a rectangular shape. Using the correct type and size of screw ensures components remain stable and that safety mechanisms, such as grounding, function as intended.