Copper vs Aluminium Wire for an EV Charger Circuit
Short answer
Aluminium conductors carry less current for a given size, so an aluminium run must be upsized relative to copper. It also requires terminations rated for aluminium, an antioxidant compound at the connections and correct torque. Done properly it is safe and much cheaper on a long run. Done casually it is a known fire risk, which is why this is not a DIY material choice.
At a glance
| 6 AWG THHN stranded copper, 100 ft | 6 AWG XHHW-2 aluminium building wire, 50 ft | |
|---|---|---|
| Cost per foot | High | Much lower |
| Size needed for the same current | Smaller | Larger, must be upsized |
| Termination requirements | Standard | Lugs rated for aluminium, antioxidant, correct torque |
| Best use | Short and medium runs | Long runs where cost dominates |
| Expansion and contraction | Less | More, which is why torque matters |
| Who should specify and install | A licensed electrician | A licensed electrician |
Choose the 6 AWG THHN stranded copper, 100 ft if…
Copper is the simpler choice and the usual one for a typical garage run. It needs no antioxidant, terminates on any rated lug, and the sizing is straightforward. On a run of twenty or thirty feet the cost difference is not large enough to be worth introducing a material with more requirements attached. Your electrician will usually default to it for this reason.
Check 6 AWG THHN stranded copper, 100 ft on Amazon
Choose the 6 AWG XHHW-2 aluminium building wire, 50 ft if…
Aluminium becomes attractive on a long run, for instance to a detached garage, where the cost difference is measured in hundreds of dollars. It must be upsized, terminated on lugs listed for aluminium, treated with an antioxidant compound, and torqued to specification. All of that is normal work for a licensed electrician and none of it is optional.
Check 6 AWG XHHW-2 aluminium building wire, 50 ft on Amazon
Related
Comparison based on published manufacturer specifications and the general consensus of owner reports. We have not tested these products side by side. Confirm current specifications and prices before buying. As an Amazon Associate we earn from qualifying purchases, at no extra cost to you.
Common questions
How much do you upsize aluminium?
Typically by two sizes relative to copper for the same ampacity, and the exact figure comes from the ampacity tables in the code for the conductor type, the insulation temperature rating and the installation conditions. The wire gauge calculator on this site gives a planning figure. The conductor your electrician installs is sized from the code tables and the inspection confirms it.
Is aluminium wiring dangerous?
Modern aluminium building wire installed with rated terminations, antioxidant and correct torque is accepted by code and used routinely, including in service entrances. The bad reputation comes from older small gauge branch circuit aluminium and from poor terminations. The risk is in the workmanship rather than the metal.
Does a long run need thicker wire anyway?
Yes, because of voltage drop, which is separate from ampacity. A long run at high current loses voltage along its length, and the usual target is to keep the drop within a few percent. The voltage drop calculator on this site shows the effect for a given length and current, and it often drives the conductor size on a detached garage run.
Can I buy the wire and have an electrician install it?
Some will and many will not, because they are responsible for the installation and want to control the materials. Discuss it before buying anything. Buying the wrong conductor type, insulation rating or size is easy, and an electrician who has to reject it has cost you money rather than saved it.
Getting your own panel and load numbers ready for an electrician? The EV Home Charging Install Planner is the paid version of these pages: 8 printable worksheets you fill in with your own numbers, plus the full PDF, $29.
How this page was researched
Specifications come from manufacturer documentation, listed safety certifications and verified owner reviews. We do not perform hands-on product testing and never claim to. Figures are researched planning information, not professional electrical advice. Last reviewed 2026-08-17.