Bending
T6 bars need generous radii, typically 2 – 3 × thickness flatwise, more for thick or edgewise bends. For tight bends, order T4, bend, then age to T6, or use a high-conductivity grade.
Electrical flat bar guide
6061 Aluminium Busbar and Electrical Flat Bar
6061 busbar is chosen when a conductor must also carry mechanical load: it is about 40 % stronger than 6101-T6 and far stronger than pure 1350, while still conducting around 40 – 43 % IACS. That makes it suited to self-supporting bars, battery and rectifier connections under vibration, and parts that double as brackets. This guide covers conductivity, resistance tables, sizes, tolerances, bending, plating and how to choose between 6061 and the high-conductivity grades.
- Alloy
- 6061 (EN AW-6061)
- Tempers
- T4, T6, T6511
- Conductivity (T6)
- About 43 % IACS
- Min. yield (T6)
- 240 MPa
When does 6061 make sense as a busbar?
Most aluminium busbar is made from high-conductivity grades: 1350 (EC aluminium, about 61 % IACS) for maximum conductivity, or 6101 and 6063 (about 52 – 57 % IACS) when a little more strength is needed. 6061 gives up some conductivity in exchange for much higher strength, hardness and machinability.
That trade is worthwhile when the busbar is not just a conductor. Typical examples are bars that span between widely spaced supports, connections in battery packs and traction equipment exposed to vibration, rectifier and electroplating bus that also carries anode weight, and machined terminals where threads must hold torque. For a simple panel busbar with short supports, a high-conductivity grade is usually more economical because a smaller section carries the same current.
Because 6061 has roughly 40 % higher resistivity than 1350, a 6061 bar needs a correspondingly larger cross-section to run at the same temperature. Always check temperature rise first, then confirm the stronger alloy is genuinely needed.
6061 vs 1350, 6101 and 6063 busbar
| Grade and temper | Conductivity (typical) | Yield strength | Best use |
|---|---|---|---|
| 1350-H112 / H14 | About 61 % IACS | About 30 – 100 MPa | Maximum conductivity, switchgear and panel bus |
| 6101-T6 / T61 / T63 | About 55 – 59 % IACS | About 100 – 170 MPa | Conductivity with moderate strength |
| 6063-T6 | About 53 % IACS | About 170 MPa min | Outdoor bus, general use |
| 6061-T4 | About 40 % IACS | About 110 MPa min | Bars that must be bent then aged |
| 6061-T6 | About 43 % IACS | About 240 MPa min | Load-bearing and vibrating bus |
| Copper C11000 | 100 – 101 % IACS | About 70 – 250 MPa | Compact bus where weight is not critical |
Copper conducts best by volume, but aluminium busbar carries the same current at roughly half the weight, so it is favoured in transport, data centres and large installations where weight and cost matter.
6061 busbar sizes, mass and DC resistance
Resistance per metre is resistivity divided by cross-section. The table uses 0.0401 Ω·mm²/m for 6061-T6 (43 % IACS) and, for comparison, 0.0283 Ω·mm²/m for 1350 (61 % IACS), both at 20 °C. Mass uses 2.70 g/cm³ and ignores corner radii.
| Thickness × width (mm) | Area (mm²) | Mass (kg/m) | 6061-T6 DC resistance (µΩ/m) | 1350 DC resistance (µΩ/m) |
|---|---|---|---|---|
| 3 × 20 | 60 | 0.162 | 668.3 | 471.7 |
| 3 × 30 | 90 | 0.243 | 445.6 | 314.4 |
| 5 × 30 | 150 | 0.405 | 267.3 | 188.7 |
| 5 × 50 | 250 | 0.675 | 160.4 | 113.2 |
| 6 × 40 | 240 | 0.648 | 167.1 | 117.9 |
| 6 × 60 | 360 | 0.972 | 111.4 | 78.6 |
| 8 × 50 | 400 | 1.080 | 100.2 | 70.8 |
| 8 × 80 | 640 | 1.728 | 62.7 | 44.2 |
| 10 × 50 | 500 | 1.350 | 80.2 | 56.6 |
| 10 × 60 | 600 | 1.620 | 66.8 | 47.2 |
| 10 × 80 | 800 | 2.160 | 50.1 | 35.4 |
| 10 × 100 | 1000 | 2.700 | 40.1 | 28.3 |
| 12 × 100 | 1200 | 3.240 | 33.4 | 23.6 |
| 12 × 120 | 1440 | 3.888 | 27.8 | 19.7 |
| 15 × 100 | 1500 | 4.050 | 26.7 | 18.9 |
| 20 × 100 | 2000 | 5.400 | 20.1 | 14.2 |
| 20 × 160 | 3200 | 8.640 | 12.5 | 8.8 |
Values are calculated for guidance. Resistance rises by about 0.28 % per °C for 6061-T6. Current rating depends on enclosure, ventilation, orientation, permitted temperature rise and AC effects in wide bars.
Typical supply range
- Thickness
- About 3 – 40 mm for extruded bar; thicker bars cut from plate
- Width
- About 10 – 200 mm extruded; wider cut from plate
- Lengths
- Up to about 6 m, or cut to length
- Edges
- Square, radiused corners, or full round edges
Composition and properties of 6061 busbar
| Element | Min % | Max % |
|---|---|---|
| Silicon (Si) | 0.40 | 0.80 |
| Iron (Fe) | — | 0.70 |
| Copper (Cu) | 0.15 | 0.40 |
| Manganese (Mn) | — | 0.15 |
| Magnesium (Mg) | 0.80 | 1.20 |
| Chromium (Cr) | 0.04 | 0.35 |
| Zinc (Zn) | — | 0.25 |
| Titanium (Ti) | — | 0.15 |
| Others, each / total | — | 0.05 / 0.15 |
| Aluminium (Al) | Remainder |
| Temper | Tensile, min | Yield, min | Elongation, min | Conductivity |
|---|---|---|---|---|
| T4 | 180 MPa | 110 MPa | 16 % | About 40 % IACS |
| T6 / T6511 | 260 MPa | 240 MPa | 8 – 10 % | About 43 % IACS |
| T6 typical | 310 MPa | 276 MPa | 12 % | About 43 % IACS |
Minimums are for extruded bar to ASTM B221 / EN 755-2. Conductivity is typical; specify a minimum and test method if it is a contract value.
Physical properties (T6)
- Density
- 2.70 g/cm³
- Resistivity at 20 °C
- About 0.040 µΩ·m
- Thermal conductivity
- 167 W/m·K
- Thermal expansion
- 23.6 µm/m·°C
- Modulus of elasticity
- 68.9 GPa
Dimensional tolerances for flat busbar
Extruded 6061 flat bar is supplied to EN 755-5 (rectangular bar) or ANSI H35.2 tolerances unless the drawing is tighter. As a guide, thickness and width tolerances widen with size: a few tenths of a millimetre for bars under about 35 mm wide, rising to around ±1 mm for bars over 100 mm wide. Busbar for laminated or stacked assemblies often needs tighter thickness control and flatness, which can be agreed or achieved by machining.
- State tolerance class or values for thickness, width and flatness
- Specify edge form: square, radius (for example R1 or R2) or full round
- Ask for surface free of dents and scratches in contact areas
Bending, drilling, joints and plating
Drilling and punching
6061 drills and punches cleanly. Deburr holes so contact faces sit flat and joint resistance stays low.
Bolted joints
Use Belleville washers to keep pressure constant through thermal cycles, clean the oxide with a wire brush and apply contact compound.
Plating
Tin plating is the usual finish for contact areas; silver for high-current or high-temperature joints; nickel for corrosive atmospheres.
Copper interfaces
Plate the aluminium or use bimetallic transition pieces to prevent galvanic corrosion where aluminium meets copper.
Insulation
Powder coat, epoxy, heat-shrink sleeving or anodising insulate bars in compact assemblies.
Where 6061 busbar is used
- Battery systems: module and pack interconnects in EV, bus and energy-storage systems exposed to vibration
- Rectifiers and electroplating: bus that also supports anode and cathode bars
- Rail and traction: conductor and earthing bars that must resist shock
- Power electronics: machined terminals and heat-sinking bus in inverters and drives
- Switchgear supports: long spans where 1350 or 6101 would sag
- Earthing: ground bars in outdoor installations, often tin plated
How to order 6061 busbar
- Size the barConfirm cross-section from current and temperature rise, then check strength.
- SpecifyAlloy and temper, thickness × width, length, edge form, tolerances and standard.
- Finish and processPlating, insulation, holes, bends and cut lengths, with drawings.
- Test and documentConductivity, tensile and dimensional results; EN 10204 3.1 certificate.
- ShipInterleaved, bundled and cased for export on EXW, FOB, CIF or DAP terms.
References and standards
- ASTM B221 – Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes
- ASTM B317/B317M – Aluminum-Alloy Extruded Bar, Rod, Tube, Pipe and Profiles for Electrical Purposes
- EN 755-2 and EN 755-5 – Extruded rod/bar: mechanical properties and rectangular bar tolerances
- IEC 60105 – Recommendation for commercial-purity aluminium busbar material
- The Aluminum Association – Aluminum Electrical Conductor Handbook
6061 aluminium (aluminum) busbar: frequently asked questions
Is 6061 a good busbar material?
Yes, when strength matters. It conducts about 43 % IACS in T6, lower than 1350 or 6101, but is much stronger. Where strength is not needed, a high-conductivity grade carries the same current in a smaller section.
What is the resistance of a 10 × 100 mm 6061 busbar?
About 40 µΩ per metre at 20 °C for 6061-T6, compared with about 28 µΩ per metre for 1350.
Can 6061-T6 busbar be bent?
Yes, with generous radii of about 2 – 3 × thickness flatwise. For tighter bends, bend in T4 and age afterwards.
Should aluminium busbar be plated?
Plating is recommended at joints, especially where aluminium meets copper. Tin is the usual choice; silver suits high-current joints.
How does 6061 busbar compare with copper?
Copper conducts about 2.3 times better than 6061-T6 by volume, but 6061 weighs less than a third as much, is cheaper and is stronger than soft copper.
Need 6061 busbar made to drawing?
Send section, temper, length, plating and quantity. We will confirm availability, testing and a delivered price.
