We buy copper bus bar.

What bus bar is and where it comes from

Bus bar is solid copper, rectangular or round, used to carry current in switchgear, panelboards, switchboards and substations. It is supplied bare or tin-plated, sometimes silver-plated in older equipment, and it is drilled, bent and formed to fit one specific lineup. The bends are the reason a section rarely suits another cabinet. Copper bar of that size is bought by fabricators as well as by scrap yards, which is why dimensions matter.

Switchgear replacement is the main source around Houston. A lineup is pulled out and the bus comes with it: main bus sections, vertical risers, breaker connections, neutral bars and the jumpers that tied one section to the next. Substation work adds heavier bar and the flexible braid that connects it to the equipment. A single lineup can produce several hundred pounds of it, most of it still straight.

• Rectangular bus bar, bare or tin-plated
• Round bar and rod from older equipment
• Neutral and ground bars from panels
• Bus supports, standoffs and insulators
• Flexible braid and laminated shunts

Dimensions come before weight

A bus bar is described by its cross-section and its length: a quarter by four inch bar, a half by six, a round bar of a stated diameter. Measure it rather than guess, because the difference between a quarter inch and three eighths is most of the metal in the piece and most of the answer. Measure the thickness at the end, where the bar has not been drilled or worn.

Weight follows from those numbers, and that is what makes bus bar easier to judge than cable. Copper has a known density, so a measured bar has a calculated weight with plating as a thin layer on top. A scale then confirms what the tape measure predicted, and the two together leave little room for argument. Two numbers, a density and a scale: that is the whole method, and it repeats.

Plating, alloy and the things that are not copper

Tin plating is normal and does not change the metal beneath it. Silver plating appears in older switchgear and in some high-current joints, and it is worth identifying. Other coatings turn up on equipment of a certain age and are handled with more care than the copper itself, because the coating is the problem rather than the metal. Say what the coating looks like rather than what it is, and let the inspection settle it.

Not every bar is copper. Aluminium bus is common in panelboards and in some switchgear, and it is lighter with a lower value. Brass and bronze appear in clamps and fittings. A magnet and a file settle most of these questions in seconds, and a buyer would rather hear the answer than find it at the yard with a scale. Aluminium is the one that catches people out, because it looks like copper under old paint.

Bus in energised equipment must be de-energised and proved dead before anything is unbolted. Site switching rules apply.

Sending a bus bar lot

List the sections by size and approximate length, with a count for each. Total weight, where you have it, is the single most useful figure on the page. Photographs of one representative piece and of the whole pile answer the plating and contamination questions at the same time, and a tape held against the bar saves a second call. A photograph with a tape measure in frame answers the size question without a second visit.

Say whether the bar is loose or still assembled in a frame. Assembled bus takes more space, more time and often needs breaking down on site before it can be loaded. Insulators, supports and hardware can travel with the metal when they came out of the same removal, and they usually should. Broken-down bus loads faster and rides better, and the insulators are the parts that break.

• Cross-section and length of each section
• Count of pieces by size
• Total weight, if known
• Plating, paint or bare copper
• Loose bar or still assembled