Electrical materials
Most residential branch circuits use copper conductors in nonmetallic sheathed cable (commonly called Romex). Aluminum is standard for large service-entrance and feeder conductors, where it is engineered for the job, but aluminum branch-circuit wiring installed in many homes built roughly 1965-1972 is a known concern that usually needs remediation rather than being left alone.
Materials are where quotes quietly differ. Wire gauge is dictated by the circuit's ampacity and the run length, not by preference, so a contractor undercutting on wire size is not saving you money - they are creating a hazard an inspector should catch.
The copper-versus-aluminum question splits by application. On the service and feeder side, aluminum is normal, cheaper, and used with the correct connectors and anti-oxidant treatment. On branch circuits, older solid aluminum wiring behaves differently from copper at connections, which is why remediation focuses on the terminations. HomeGuide's 2026 data notes copper pigtailing at connection points runs about $50-$75 per outlet, which is dramatically cheaper than a whole-house rewire at $12,000-$36,600. If someone quotes only the rewire without mentioning remediation as an option, ask why.
Conduit versus cable is largely driven by location and local rules - some jurisdictions require conduit where others permit NM cable, and exterior, garage, and unfinished-basement runs have their own requirements. This is another place where the adopted local code, not a general rule, decides.
One thing you can check without any trade knowledge: everything installed should be listed by a recognized testing laboratory. Ask that the quote specify listed materials and that any unusual product be named.
Choosing electrical materials
The judgement calls that decide the bill, before anyone quotes you.
- Ask for aluminum remediation as an option, not just rewiring If aluminum branch wiring is found, a connection-level remediation is often available at roughly $50-$75 per outlet versus a five-figure rewire. Get both priced.
- Wire gauge is not negotiable It follows the breaker size and run length. If a contractor offers a cheaper price by using smaller wire on the same breaker, walk away.
- Confirm materials are listed Ask the quote to state that all devices, breakers and cable are listed by a recognized testing lab. Unlisted imported breakers are a real problem in online marketplaces.
- Local rules decide conduit vs. cable Do not assume what your neighbor's house has is what yours can have. Your building department's amendments govern.
- Ask what happens to the walls Rewiring in finished walls means drywall or plaster repair, which HomeGuide puts at $1,000-$5,000. Confirm whether it is in the quote or your problem.
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Where these figures come from
Sources last checked
- HomeGuide - Cost to Replace Knob and Tube Wiring (2026) · retrieved 2026-07-25
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