Contact preparation
Aluminium forms an insulating oxide in seconds. Abrade contact faces, apply contact grease immediately and assemble promptly.
Busbar guide
6060 T4 / T5 / T6 Electrical Aluminium Busbar
6060 is a lean, heat-treatable Al-Mg-Si extrusion alloy that makes busbars stronger and stiffer than pure-aluminium grades while keeping conductivity at roughly 50 – 58 % of copper. It is the right choice when a bar must carry current and also act as a structural member, span between supports or hold its shape through repeated bolting. This guide covers its properties by temper, how to size it against copper, jointing practice and the standard size range.
- Alloy
- 6060 (AlMgSi)
- Tempers
- T4, T5, T6, T66
- Conductivity
- about 28 – 34 MS/m
- Standards
- EN 755-2 · EN 573-3
Why use 6060 for busbar?
Busbar alloys sit on a spectrum. Pure grades such as 1350, 1070 and 1060 conduct best (about 61 – 63 % IACS) but are soft, so long bars sag, threaded joints creep and the bars dent easily. Alloys such as 6082 and 6061 are strong but conduct markedly less. 6060 and its close relative 6101 sit in between.
Because 6060 has only small amounts of magnesium and silicon, most of the solute comes out of solution during ageing, leaving a conductive matrix. At the same time those precipitates roughly double or triple the yield strength of pure aluminium. 6060 also extrudes very easily, so it can be pushed into wide flat bars, bars with radiused edges or special conductor shapes at low cost.
Typical uses are switchgear and panel busbars that span between insulators, busbar trunking, earthing bars, battery-system interconnects and conductors that double as mounting rails. Where the highest conductivity is the only goal, 1350 or 6101 is preferred; where 6060's strength is not enough, 6063 or 6082 follow.
6060 chemical composition (wt %)
| Element | Limit |
|---|---|
| Silicon (Si) | 0.30 – 0.6 |
| Magnesium (Mg) | 0.35 – 0.6 |
| Iron (Fe) | 0.10 – 0.30 |
| Copper (Cu) | ≤ 0.10 |
| Manganese (Mn) | ≤ 0.10 |
| Chromium (Cr) | ≤ 0.05 |
| Zinc (Zn) | ≤ 0.15 |
| Titanium (Ti) | ≤ 0.10 |
| Others each / total | ≤ 0.05 / 0.15 |
| Aluminium (Al) | Remainder |
EN 573-3 limits for EN AW-6060 (AlMgSi). Low Mn and Cr keep conductivity high.
Mechanical and electrical properties by temper
Mechanical values below are the EN 755-2 minimums for extruded bar. Conductivity is typical and depends on the exact ageing practice: the more fully aged the bar, the higher the conductivity.
| Temper | Thickness | Rm min | Rp0.2 min | Elongation A min | Typical conductivity |
|---|---|---|---|---|---|
| T4 | ≤ 25 mm | 120 MPa | 60 MPa | 16 % | lowest, about 28 – 30 MS/m |
| T5 | ≤ 5 mm | 160 MPa | 120 MPa | 8 % | about 30 – 34 MS/m |
| T5 | 5 – 25 mm | 140 MPa | 100 MPa | 8 % | about 30 – 34 MS/m |
| T6 | ≤ 3 mm | 190 MPa | 150 MPa | 8 % | about 30 – 33 MS/m |
| T6 | 3 – 25 mm | 170 MPa | 140 MPa | 8 % | about 30 – 33 MS/m |
| T66 | ≤ 3 mm | 215 MPa | 160 MPa | 8 % | slightly lower |
| T66 | 3 – 25 mm | 195 MPa | 150 MPa | 8 % | slightly lower |
Physical properties
- Density
- 2.70 g/cm³
- Electrical conductivity
- about 28 – 34 MS/m (about 48 – 58 % IACS) by temper
- Thermal conductivity
- about 200 – 210 W/m·K
- Thermal expansion
- about 23.4 µm/m·°C
- Modulus of elasticity
- about 69 GPa
- Melting range
- about 585 – 650 °C
Sizing 6060 busbar against copper
Annealed copper conducts about 58 MS/m. A 6060-T5 bar at about 32 MS/m therefore needs roughly 1.8 times the cross-section of copper for the same resistance. Because aluminium is only 30 % as dense as copper, that larger bar still weighs about half as much, and usually costs far less.
In practice current rating is set by temperature rise, not resistance alone. Larger aluminium bars have more surface area and dissipate heat better, so the area ratio needed for equal temperature rise is often a little below the resistance ratio. Final ratings should be confirmed by calculation or a temperature-rise test to the switchgear standard (for example IEC 61439).
| Bar (mm) | Cross-section (mm²) | Weight (kg/m) | DC resistance at 20 °C, approx. (µΩ/m) at 32 MS/m |
|---|---|---|---|
| 3 × 20 | 60 | 0.16 | 521 |
| 3 × 30 | 90 | 0.24 | 347 |
| 5 × 30 | 150 | 0.41 | 208 |
| 5 × 50 | 250 | 0.68 | 125 |
| 6 × 60 | 360 | 0.97 | 87 |
| 8 × 80 | 640 | 1.73 | 49 |
| 10 × 50 | 500 | 1.35 | 62 |
| 10 × 100 | 1000 | 2.70 | 31 |
| 12 × 120 | 1440 | 3.89 | 22 |
| 15 × 150 | 2250 | 6.08 | 14 |
Weights from 2.70 g/cm³; resistance = 1 / (conductivity × area), ignoring corner radii. Use our electrical resistance calculator for other sizes.
Jointing, plating and insulation
Bolting
Use spring (Belleville) washers or wide washers to maintain clamping force as the joint heats and cools; 6060's higher strength resists creep better than 1xxx bars.
Plating
Tin or silver plating stabilises contact resistance; nickel is used for harsh atmospheres. Plated or bimetallic connections are recommended where aluminium meets copper.
Insulation
Epoxy powder coating, heat-shrink sleeving (PVC, polyolefin or silicone) or insulating paint, chosen to the voltage and temperature class.
Bending
T4 bends most easily; T5 and T6 bend flatwise at about 1 × thickness up to 12 mm and 2 × above, with edgewise bends needing larger radii.
Testing
Conductivity, bend and temperature-rise tests can be specified per order.
6060 busbar sizes and tolerances
Supply range
- Thickness
- about 2 – 40 mm
- Width
- about 10 – 200 mm
- Length
- up to about 6 m, or cut to length
- Edges
- Square, radiused or full-round edges
- Other shapes
- Round, square and special conductor profiles
- Tolerances
- EN 755-5 for rectangular bar (width and thickness tolerance increase with size)
- Certificate
- EN 10204 3.1 with chemistry, tensile and conductivity results
Common flat sizes run from 3 × 20 mm up to 15 × 150 mm and wider. Bars are bundled and boxed with interleaving to protect contact faces.
6060 versus other busbar alloys
| Alloy | Typical conductivity | Strength | Best for |
|---|---|---|---|
| 1350 / 1070 | about 61 – 63 % IACS | Low | Maximum conductivity, short supported runs |
| 6101-T6/T61/T63 | about 55 – 59 % IACS | Medium | High-conductivity structural bus |
| 6060-T5/T6 | about 50 – 58 % IACS | Medium | General structural busbar, cost-effective extrusion |
| 6063-T6 | about 53 % IACS | Medium | Similar to 6060, slightly stronger |
| 6082-T6 | about 40 – 45 % IACS | High | Heavily loaded or long-span bars |
References and standards
- EN 755-2 – Extruded rod/bar, tube and profiles: mechanical properties
- EN 755-5 – Extruded rectangular bars: tolerances on dimensions and form
- EN 573-3 – Chemical composition and form of wrought products
- IEC 60105 – Recommendation for commercial-purity aluminium busbar material
- IEC 61439 – Low-voltage switchgear and controlgear assemblies (temperature-rise verification)
- Copper Development Association – Copper for Busbars (comparative design data)
6060 busbar: frequently asked questions
What is the conductivity of 6060 aluminum busbar?
Typically about 28 – 34 MS/m (roughly 48 – 58 % IACS), depending on temper. Fully aged T5 or T6 bars conduct better than T4.
Is 6060 or 6101 better for busbar?
6101 is designed as a conductor alloy and usually conducts a little better. 6060 is cheaper and more widely extruded and is fully adequate for most panel and trunking busbars.
How much bigger must an aluminium busbar be than copper?
For equal resistance, a 6060 bar needs roughly 1.8 times the copper cross-section. It still weighs about half as much. Confirm ratings by temperature-rise calculation or test.
Which temper should I choose?
T5 or T6 for most bars: good strength and conductivity. T4 if bars are bent tightly during installation. T66 where extra strength is needed.
Can 6060 busbar be connected to copper?
Yes, but use tin- or silver-plated contact surfaces or bimetallic connectors and contact grease to avoid galvanic corrosion at the joint.
Need 6060 busbar for a switchgear or battery project?
Send sizes, temper, finish and quantity. Metline will confirm availability, test certificates and delivery worldwide.
