How should drawing requirements be specified for industrial heating elements?

To specify drawing requirements for industrial heating elements, first define power, voltage and phases from the actual duty, then select sheath diameter and material by surface load so that load stays within a range that avoids shortened life. The drawing should state heated and cold lengths, outside diameter, bend radius, centre distance, flange details and terminal type, together with dimensional tolerances and ingress protection; for multiple elements, show relative positions, wiring arrangement and sensor points. Issue a revision-controlled drawing with acceptance criteria covering cold resistance, insulation resistance, dielectric test, leakage current and heat-up curve, and verify mounting dimensions against the real installation, noting medium, pressure and flow where relevant.