Box dimensions are always written in the same order: Length × Width × Height (L × W × H). This is the universal convention used by packaging suppliers, carriers, and retailers worldwide. For example, a box listed as 12 × 9 × 4 in is 12 inches long, 9 inches wide, and 4 inches. Choosing the right electrical junction box size is crucial for safety and code compliance in your US projects. Written by Fasih Rauf, packaging consultant at Dream Custom Boxes. Whether you are shipping products to customers, displaying merchandise on retail shelves, packing subscription. Wiring diagram shows both PNP and NPN wiring. Actual units use PNP status indicator, NPN status indicator, or neither. 81 ft)]. stallation and use of boxes.