Issuing body: EN
EN 13601
Copper rod, bar and wire for electrical purposes
EN 13601 covers copper rod, bar and wire for general electrical purposes, including the Cu-ETP material designation CW004A used for most busbar. Its temper designations are the ones that appear on a mill certificate: R220 or H040 soft annealed at 220 to 260 N/mmΒ², R240 or H065 half-hard at 240 to 300 N/mmΒ², and R290 or H090 hard at 290 to 360 N/mmΒ². As temper hardens, yield strength and hardness rise while ductility falls, and the minimum radius the bar will take without cracking on the outer fibre grows with it. Springback grows with it too.
Technical background
Bending
Springback compensation in busbar bending
How to predict and cancel springback in copper busbar bending: the governing ratios, a worked calculation, overbend by EN 13601 temper, and CNC offset tables.
Materials and finishing
Copper temper and minimum bend radius
How EN 13601 tempers R220, R240 and R290 set the minimum bend radius of copper busbar, how to read a mill certificate, and when annealing is the wrong answer.
Bending
Edgewise versus flatwise busbar bending
Why edgewise busbar bending force scales with the square of bar width, where buckling sets the limit, and how to choose between twisting, joints and plate.
Materials and finishing
Specifying flatness, straightness and twist after processing
How punching, shearing and bending distort busbar, how to measure bow, camber and twist properly, and what tolerances are realistically achievable.