How should cold-end length be specified for commercial heating elements?

Cold-end length for commercial heating elements is set by terminal-area temperature, insulation thickness and terminal temperature rating, keeping the live heated section clear of the connection zone. For ovens, steamers and holding cabinets, measure the distance from the mounting plate to the outer insulation face, then add roughly 10-20 mm; where the terminal box sits near the oven mouth or ambient temperature runs high, use the upper allowance and verify the terminal rating. Cross-check against sheath diameter, watt density and power so an over-long cold end does not shorten the heated section and raise watt density. Record the measured cold end against drawing tolerance at acceptance, and confirm it stays out of the hot zone.