Bus bar and tube · copper and aluminum
Bus bar buyers in New York
Bus bar is the simplest material on this site and the easiest to get wrong. There is no jacket, no print and no footage to argue about — only alloy, dimensions, plating and whether the bar is straight.
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Bus bar is valued on alloy, cross-section, length and plating. Copper weighs about 0.321 lb per cubic inch and aluminum about 0.098, so a 1/2 in by 6 in copper bar is roughly 11.6 lb per foot. Measure with calipers, photograph with a rule, and state the alloy and plating; those five facts decide the price.
Bar, tube and the dimensions that decide everything
Bus bar is conductor in a solid form. Rectangular bar is the default: flat, rigid, drilled and bolted to insulators, and used for switchgear bus, panelboard bus, substation connections and the links between transformers and switchboards. Standard thicknesses run from about 1/8 in to 1/2 in, and widths from 1/2 in to 12 in, though the sizes that matter in New York switchgear and substation work cluster between 1/4 x 2 in and 1/2 x 6 in.
Tube bus is the other form. Copper pipe and extruded aluminum tube carry very high current with less metal than a solid bar, because the current crowds toward the surface at higher frequencies and because a tube is stiffer per pound. Aluminum tube is common in substation high-current runs where the weight of a solid bar would need heavier supports.
Channel bus and custom profiles also appear, usually as part of a switchgear assembly rather than as loose stock. They are reviewed on the same facts — alloy, section, length and condition — but with the understanding that a proprietary profile may only fit the equipment it came out of.
Alloy and temper: what the bar is made of
Copper bus is usually electrolytic tough pitch copper, C11000, at roughly 100 percent IACS conductivity. Oxygen-free copper, C10100, appears in vacuum and high-reliability applications and is identifiable from the mill certificate rather than from the surface. Both are commonly supplied soft for bending and forming, or half-hard where the bar has to stay straight and resist sag between supports.
Aluminum bus is extruded from 6101-T6 or 6061-T6. The T6 temper is what gives extruded aluminum bus its strength; it is not a heat treatment that survives welding, which is why a welded aluminum bus section is either re-tempered or accepted at reduced strength. Aluminum bus also needs a larger cross-section than copper for the same current, so a bar that looks generous in aluminum may be equivalent to a much smaller copper bar.
Alloy identification is the hardest part of a loose bus lot, and it is where documentation pays. Mill stamps, heat numbers, purchase records and the equipment the bar came out of are all evidence. Without them, a buyer is looking at metal of unknown conductivity, and unknown conductivity is priced as scrap.
Plating, joints and the marks that reduce value
Bus bar is plated for one reason: to keep the contact resistance at a bolted joint low and stable. Tin plating is the general-purpose finish and is common on panel and switchboard bus. Silver plating is used on switchgear contacts and on joints where the lowest resistance matters, and it is visibly brighter until it tarnishes. Both finishes are thin, measured in fractions of a thousandth of an inch, and both are removed by abrasion.
That matters for resale. A straight, undrilled, fully plated length of bus is a reusable product and is bought as bus. A length with holes drilled at intervals, bends that do not suit the next application, welded extensions or worn plating at the joints is a cut-off, and cut-offs are weighed. Arc marks, heat discolouration and pitting are worse than holes, because they indicate a fault and can only be cut out.
Insulation and paint are neutral. Heat-shrink booting, epoxy coating and paint are removed before the bar is reused or weighed, and they add weight that is not metal. Say whether the bar is bare, sleeved or painted, because it changes both the yield and the handling.
How to measure and photograph a bus lot
Use calipers, not a tape. Bus thickness is often 1/4 in or 3/8 in, and a tape measure cannot distinguish 0.25 in from 0.24 in across a burred edge. Measure thickness at three points along the bar and width at three points, and record the smallest readings, because that is what determines the section. Measure length separately for each piece, and note whether the ends are square cut or sheared.
Photograph the bar with a steel rule laid flat alongside it, one image per size group, plus a close-up of any stamp, plating and joint face. A photograph of a stacked pile tells a buyer almost nothing; a photograph of three bars with a rule across them answers the whole question. If there is a mill certificate or a purchase record, photograph that too.
Then check the weight against the arithmetic. A 1/2 x 6 in copper bar is three square inches of section, which is 36 cubic inches per foot, which at 0.321 lb/in³ is about 11.6 lb per foot. If the scale says something very different, either the dimensions or the alloy is not what it appears to be.
| Bar size | Section (in²) | Copper lb/ft | Aluminum lb/ft |
|---|---|---|---|
| 1/4 x 2 in | 0.50 | 1.93 | 0.59 |
| 1/4 x 4 in | 1.00 | 3.85 | 1.18 |
| 1/4 x 6 in | 1.50 | 5.78 | 1.76 |
| 3/8 x 4 in | 1.50 | 5.78 | 1.76 |
| 3/8 x 6 in | 2.25 | 8.67 | 2.65 |
| 1/2 x 2 in | 1.00 | 3.85 | 1.18 |
| 1/2 x 4 in | 2.00 | 7.71 | 2.35 |
| 1/2 x 6 in | 3.00 | 11.56 | 3.53 |
Specification
What a buyer needs to know about this cable
Every row below changes what a lot is worth. If the reel tag is gone, the jacket print and a cut end usually answer most of it.
Missing detail is not a problem — say what is missing and the review works from photographs.
| Materials | Electrolytic tough pitch copper C11000, oxygen-free C10100, or 6101-T6 and 6061-T6 aluminum |
|---|---|
| Bar sizes | 1/8 in to 1/2 in thick, 1/2 in to 12 in wide; 1/4 x 2 in through 1/2 x 6 in covers most switchgear work |
| Tube bus | Copper pipe and extruded aluminum tube, used for high-current runs where weight matters |
| Temper | Soft annealed copper for forming, half-hard for structural bus; T6 for extruded aluminum |
| Plating | Bare, tin plated for bolted joints and corrosion resistance, or silver plated for switchgear contacts |
| Standard lengths | 10 ft and 12 ft straight lengths; shorter cut pieces from switchgear and panel work |
| Density | Copper 0.321 lb/in³, aluminum 0.098 lb/in³ — the basis of every weight calculation |
| Condition signals | Bends, drilled holes, weld porosity, worn plating, arc marks, heat discolouration, paint and insulation |
Constructions
Bus material we review
Straight, plated and undrilled is a product. Drilled, bent and marked is a weight.
Switchgear bus bar
Copper bar from panelboards and switchboards, often tin plated and drilled for bolted joints. Straight sections with clean plating are worth reusing; drilled cut-offs are weighed.
Substation bus and tube
Heavy copper bar, aluminum tube and connector stock from substation work. Reviewed on alloy, wall thickness and the condition of welded joints.
Silver-plated contact bar
Switchgear contact and joint bar with silver plating. The plating is a specification advantage until it is worn through, at which point the bar is copper.
Aluminum extruded bus
6101-T6 and 6061-T6 bar and tube, usually from high-current distribution. Larger sections than copper for the same current, and a different weight basis entirely.
Bent and drilled cut-offs
Offcuts from panel fabrication with holes, bends and sheared ends. Reviewed on weight, with any reusable straight lengths separated out.
Mixed bus and conductor
Bus bar mixed with heavy cable and fittings from a demolition or upgrade. Separated by metal and form, it recovers far more than an unsorted pile.
New York
Bus bar in the New York market
Bus bar turns up whenever switchgear is replaced, a substation is rebuilt or a plant closes. New York's older building stock is full of panelboards and switchboards being replaced during electrical upgrades, and each one releases copper bus that is straight, plated and often in useful lengths. Substation work releases heavier bar and tube, sometimes in whole spares that were never installed.
Demand comes from panel builders, switchgear assemblers and contractors who need a specific section quickly. Because bus is sold by dimension rather than by catalog number, a clean length of 1/4 x 4 in copper is useful to almost anyone building a panel, while a bent and drilled piece is useful only to the person who bent it.
What helps a New York lot move
- Alloy and temper, with any stamp or certificate
- Thickness, width and length measured with calipers
- Plating type and condition at the joints
- Whether the bar is straight, drilled, bent or welded
- Total weight, and whether tube or bar
Seller questions
Questions sellers ask
How do I calculate the weight of a bus bar?
Multiply the cross-section in square inches by 12 to get cubic inches per foot, then multiply by the density: about 0.321 lb/in³ for copper and 0.098 lb/in³ for aluminum. A 1/2 x 6 in copper bar is 3 in², so 36 in³ per foot, or roughly 11.6 lb per foot. The same bar in aluminum is about 3.5 lb per foot.
Does plating affect what the bar is worth?
It affects whether the bar can be reused as bus. Tin and silver plating keep joint resistance low and stable, and a fully plated, straight length is a product. Worn plating at the joints, arc marks or heavy corrosion push the bar toward metal value, because the damaged section has to be cut out before it can be installed.
Can aluminum and copper bus be sold together?
They can be collected together but are weighed and valued separately, because the metals have very different values per pound and different densities. Mixing them in one weight is the most common way sellers lose money on a bus lot.
What is tube bus used for?
High-current runs where weight and stiffness matter, particularly in substations and large industrial distribution. A tube carries more current per pound than a solid bar of the same outside dimension, and it is stiffer, so it needs fewer supports over a long span.
What is the best way to photograph bus bar?
Lay a steel rule along the bar and photograph the bar and rule together, one image per size group, with a close-up of any stamp, joint face or plating damage. Add the length of each piece and the total weight. A photograph of a stack without a scale reference cannot be used to establish section.
Keep reading
Related pages
- Substation wire and bus buyersStation bus, connectors and jumpers
- Copper wire buyersCopper conductor and metal value
- Aluminum wire buyersAluminum conductor and alloy
- Medium voltage cable buyersCable that terminates on the bus
- Data center cable buyersBusway and distribution material
- Plant liquidation cable buyersSwitchgear and plant bus stock
Next step
Send the lot details
Include the storage city, how it is stored and what can reach it. If you have photographs of reel tags or jacket print, send them with the enquiry.
Send the lot
One desk reviews every lot that arrives.
Prefer to talk? 614-715-3047 · saleselectricalbuyers@gmail.com