American Wire Gage is the common standard for measuring wire diameter. Larger numbers represent smaller diameter wire, and vice versa. A cable is usually described by its AWG size followed by the number of wires (conductors) it contains. For example, a cable listed as 22-4 is a four-conductor cable made up of four wires, each 22 gauge (most system makers specify 22 gauge as the minimum for their systems to be installed to UL standards).