Knob-and-tube and aluminum wiring: what older-home owners should know

Lancaster County has no shortage of older homes, and with them come wiring methods that aren’t used today. Two come up often: knob-and-tube and aluminum branch wiring.

Knob-and-tube wiring

Common in homes built before roughly 1950, knob-and-tube wiring uses single insulated wires run through the walls on ceramic knobs and tubes. You may spot it in attics and basements. It has no ground wire, its insulation can become brittle with age, and it wasn’t designed for modern electrical loads. It becomes a particular concern when it’s buried in insulation or has been modified over the years. Many insurers ask about it.

Aluminum branch wiring

Used in some homes built from the mid-1960s to the mid-1970s, aluminum branch wiring expands and contracts more than copper. Over time that can loosen connections at outlets, switches, and fixtures and lead to overheating. Warning signs include warm outlets or switch plates, flickering lights, and a burning smell.

What to do

Don’t panic, but don’t ignore it either. Have a qualified electrician look at the wiring. Depending on what’s there, the fix might be targeted repairs or a full rewire, and we’ll explain the choices and what each involves.

See our home wiring and rewiring page, or call or text for a free quote.