Electrical Busbar

The alloy grade sets the trade between conductivity and shop behaviour. C11000 electrolytic tough pitch copper is 99.9 percent pure and carries at least 100 percent IACS - the default for busbar - but it machines gummy and wears tooling, so feeds are slowed. C10100 oxygen-free copper reaches about 101 percent IACS and is chosen when brazing, soldering or butt-welding is on the drawing. C12200 solders easily at a conductivity penalty; C14500 tellurium copper keeps near-pure conductivity while machining like free-cutting stock; C360 brass is the most machinable copper alloy of all.

Stock lengths start from our copper bar stock range, and the trade-off maths is in copper versus aluminium.

Commercially pure 1100 and 1350 aluminium sit at 50 to 61 percent IACS, with 1100 the stronger of the two; the 6000-series structural grades weld well - 6061 near 40 percent IACS, 6063 near 50 - and 6101 is the standard electrical grade at 57 to 61 percent. Aluminium conducts about 61 percent of copper per unit area at less than a third of the weight, close to twice the conductivity per pound. Tempers matter: soft O-temper bends to tight radii, the half-hard H01-H04 range is the default for rectangular busbar, and hard temper suits machining but not bending. See the aluminium busbar range.

Where joints absorb vibration, thermal growth or mounting misalignment, a high-current flexible busbar stacks thin conductive layers and welds the ends solid - no separate lugs - carrying more current per section and shedding heat better than a solid bar. For irregular or one-off shapes, epoxy powder coating is applied after every bend, punch and mill, so the insulation stays uniform where shrink tubing or dip coating cannot. Both routes start from custom busbar design from your drawing with a DFM review before tooling.

Choosing the conductor alloy is the first real decision on any electrical busbar drawing. The cross-reference below packs the five grades our shops actually cut - the busbar conductor material guide we hand to engineers in the first meeting - with the typical published numbers that sizing and joint design hang on.

The C11000 C10100 busbar copper alloy split is about process, not rating: C11000 stays cheaper and stiffer for cut-and-drill work, while C10100 remains sound through brazing heat. The grade choice rarely changes the joint hardware, but it does shift the bending allowance: half-hard C11000 and C14500 hold tighter radii than annealed OFHC, which flows and stretches under clamp pressure. Values in the table are typical published figures; confirm the exact temper against your DFM drawing before releasing tooling. The wider conductivity-versus-weight trade is explained in our copper versus aluminium notes, and once the grade is chosen the next step is sizing, and that pass starts by reading the ampacity chart.

Once the alloy is settled, sizing an electrical busbar is a three-pass job rather than a single lookup. The flow below is the same one our engineers run in the DFM meeting, with a conversion table that sketches the first pass in millimetres.

1. Write down the continuous current, the site ambient and the rise you can tolerate, then read the busbar ampacity chart for the starting copper section.
2. Decide the conductor family: stay with C11000 where cabinet space or heat is tight, or move to 6101 aluminium where weight and material cost dominate.
3. Send the chosen section, the bend envelope and the terminal pattern to engineering; DFM confirms rise, support loads and plating before tooling.

The aluminium column applies the same width-first rule we use elsewhere: extra width beats extra thickness because it also doubles the radiating face. Parallel runs share heat, so trim each bar's independent rating by a small planning margin before cutting. These rows are planning estimates, not rated values; the final section is locked against your enclosure, supports and joint layout in the DFM review. Panel builders who want the background read what a busbar does inside a switchboard.