Wattages The above chart is based on a watt density of 30 watts per square inch of surface. The watt density should be varied, depending on operating temperature in accordance with the following table. Operating Temperature Watts/square inch 300°F 40 400°F 30 500°F 21 600°F 12 700°F - 900°F (Max.) 10 To compute wattage, multiply length (less 1\") x width x watts per square inch based on above table. On units with mounting holes, reduce length by an additional 2\" when computing wattage. Voltage Standard voltages are either 120V or 240V. Other voltages are available. Tolerances Width: ±.03\" Thickness: .187\" nominal Length: Up to 24\", ±1/16\" 24\" to 48\", ±1/8\" Lengths over 48\", consult factory. Terminal Height: 3/4\" nominal Wattage tolerances are held to ±5%, -10% at rated voltage. Mounting Holes Units are supplied without mounting holes. 1/2\" x 5/16\" mounting holes, one each end, may be supplied if specified. Hole center is 1/2\" from end. Terminals are 1 1/4\" from end on types SSA, SSB, and SO on units with mounting holes. Other mounting hole sizes and locations are available. Consult factory.