If your home was built before 1965, there’s a chance you have knob-and-tube wiring somewhere. Aluminum branch wiring shows up in homes from 1965 to about 1975. Both are workable but require specific handling.
Knob-and-tube wiring
The original residential electrical — copper wires held in place with ceramic knobs and routed through ceramic tubes. Common in homes built before 1950, sometimes lingering in attics and basements of homes up to 1965.
When knob-and-tube is dangerous
- Buried in modern insulation — designed to dissipate heat through open air. Pack insulation around it and it overheats. Major fire risk.
- Spliced with modern wiring incorrectly — mixing old and new without proper junction boxes.
- Overloaded — original 15A circuits running modern computers, AC units, microwaves.
- Insulation aged out — the rubber insulation crumbles after 60+ years.
When it’s acceptable
Limited knob-and-tube in unfinished basements or open attics, not buried in insulation, not overloaded, in good visible condition. Some insurance companies still accept it; others won’t cover the home until it’s replaced.
What to do
Full rewire to modern Romex / NMD90 is the gold-standard fix. We don’t do full rewires — it’s a specialty that often involves opening walls. We can quote partial rewires (one room, one circuit) and we partner with rewire specialists for whole-home jobs.
Aluminum branch wiring (1965–1975)
Solid aluminum wire used in branch circuits during a copper shortage. Not inherently dangerous — aluminum carries current fine — but the connections to switches, outlets, and breakers loosen over time as the metal expands and contracts. Loose connections heat up. Heat is the danger.
How to make aluminum safe
- CO/ALR-rated switches and outlets — specifically designed for aluminum. Identifiable by “CO/ALR” printed on the device.
- Purple AlumiConn connectors at every junction — properly torque-rated aluminum-to-copper transitions.
- Antioxidant paste on the connections.
- Pigtailing to copper at all device boxes — the modern accepted fix.
What we can do
Whole-home aluminum pigtailing (typically $2,500–$5,000) and panel-level termination upgrades. Outlet-by-outlet swaps when you’re renovating. Start a quote with aluminum wiring noted — we’ll send specific guidance.
Insurance implications
Many insurers ask about both knob-and-tube and aluminum at policy renewal. Some won’t insure homes that have either; others require a clean ESA inspection in the last 5 years. Always tell us if your insurer flagged something — we’ll target the fix to what they want to see.