The primary number used to identify an item of production or a range of items of production, by the manufacturer (individual, company, firm, corporation, or Government activity) which controls the design, characteristics, and production of the item by means of its engineering drawings. The primary number used to identify an item of production or a range of items of production, by the manufacturer (individual, company, firm, corporation, or Government activity) which controls the design, characteristics, and production of the item by means of its engineering drawings. Quality tools are defined as an instrument or technique to support and improve the activities of quality management and improvement. 81 ft)] for standard cable lengths. Wiring diagram shows both PNP and NPN wiring. Dimensions are shown in mm (in. Actual units. Electrical distribution boxes are used in commercial and residential buildings and are part of the electrical system, also known as switchboards.