Yes, aluminium conducts both electricity and heat, but its conductivity depends on alloy, temper and temperature. A value quoted for high-purity electrical aluminium should not be applied to every structural plate, bar or extrusion. For an electrical purchase, specify conductivity as a requirement rather than assuming it from the word “aluminium.”
The useful comparison is not simply aluminium versus copper. It is the required electrical performance, conductor cross-section, mechanical support, connection arrangement and operating environment of the finished assembly.
What % IACS Means
IACS stands for International Annealed Copper Standard. A conductivity reported as a percentage of IACS compares the material with that reference at a defined temperature. It is not an aluminium purity percentage, nor does 61% IACS mean that only 61% of the current passes through the part.
Electrical Conductivity Changes with Alloy and Temper
| Material condition | Conductivity at 20°C | Data status and scope |
|---|---|---|
| 1350-H111 | At least 61% IACS | Minimum stated in Hydro’s 1350 product information |
| 6101-T6 | 55% IACS minimum | Hydro extrusion data; listed section range 3.20–12.50 mm |
| 6101-T64 | 59.5% IACS minimum | Hydro extrusion data; listed section range 3.20–25.00 mm |
| 6061-T6 / T6511 | 43% IACS | Typical reference value in Hydro’s extrusion data; not a batch acceptance result |
Sources: 1350 information, 6101 data sheet and 6061 data sheet. The values illustrate material-condition differences. They are not measured results for Sasa Aluminum shipments and do not establish that every dimension or product form is available in these conditions.
Keep minimum, typical and measured values separate. A typical conductivity helps initial comparison. A minimum in the governing purchase specification is an acceptance requirement. An actual test result belongs to an identified batch, test method and temperature. One cannot silently replace another.
Does an Aluminium Conductor Need a Larger Section?
For a uniform conductor, resistance follows R = ρL/A, where ρ is resistivity, L is length and A is cross-sectional area. At the same temperature and length, a material at 61% of the reference conductivity needs approximately 1/0.61, or 1.64 times the reference area, to have the same DC resistance.
This is an illustrative resistance calculation—not a cable-sizing rule. Allowable current also depends on heat dissipation, ambient conditions, insulation, installation arrangement and the complete assembly. AC applications may introduce additional effects. A qualified electrical designer must determine the appropriate conductor and protection for the actual installation.
Why Connections Deserve Their Own Review
Bulk conductivity describes the metal along the current path. It does not fully describe a joint. Aluminium’s surface oxide, contact pressure, the connector materials and the service environment can affect contact resistance and heating. A high-conductivity bar can still perform poorly if its connections are unsuitable.
For a bolted busbar or terminal, document the approved connection design, surface treatment, compatible connector and inspection requirements. Do not copy a tightening torque, surface-preparation method or joint compound from an unrelated assembly. Follow the equipment and connector manufacturer’s validated procedure and applicable installation requirements.
Corrosion and mixed-metal contact
Where moisture can reach a joint, the combination of metals and the ability to retain electrolyte matter. A material selection should consider the whole connection, including coatings, fasteners and drainage. Calling aluminium “corrosion resistant” is not enough to qualify an exposed electrical joint.
Electrical Conductivity Is Not Thermal Conductivity
Electrical conductivity describes current flow; thermal conductivity describes heat transfer. They use different units and are not interchangeable design inputs. A heat sink needs a thermal design that accounts for geometry, interface resistance and cooling conditions, while a current-carrying part also needs an electrical and connection assessment.
Do not assign one pure-aluminium thermal value to every alloy. Similarly, a polished surface or an anodized appearance does not establish the bulk conductivity of the underlying metal. When the surface itself must conduct, identify the contact areas and any coating restrictions separately from the base-material specification.
Choosing the Material for a Conductive Component
Start by stating whether the part primarily carries current, transfers heat or provides structural support. A high-conductivity grade may be appropriate when resistance is the limiting factor; another alloy or temper may be necessary where mechanical loading controls. The right answer may also involve changing section geometry rather than simply choosing a higher conductivity number.
For an inquiry involving commercially pure aluminium flat products, the 1000-series aluminium sheet range can help identify possible product forms. Do not assume that any 1xxx sheet is certified conductor stock: the exact alloy, temper and required conductivity still need confirmation.
What to Include in an Electrical-Material RFQ
- Alloy, full temper, product form, dimensions and quantity.
- Required minimum conductivity, reference temperature, test method and governing specification.
- Mechanical-property requirements and critical dimensional tolerances.
- Surface finish, contact-area treatment and coating restrictions.
- Service environment, connection arrangement and required inspection documentation.
If a drawing specifies copper and aluminium is being considered as an alternative, request design approval before ordering. Equal dimensions do not mean equal resistance, and an alloy substitution can affect connections and thermal behaviour as well as material cost.
Discuss the Material Specification
Send your material specification, dimensional drawing, required conductivity and inspection scope. Pricing and material review should be based on the complete requirement, not an unqualified conductivity figure.
Post time: Jul-10-2025