What older wiring looks like
- Knob-and-tube. Separate wires on ceramic knobs, common in homes from before the 1940s. No ground, ageing insulation, and it should not be buried under attic insulation.
- Two-prong outlets. Usually means no ground wire. Swapping in a three-prong outlet without a ground is unsafe.
- Aluminum branch wiring. Found in some homes from the mid-1960s to the mid-1970s. Connections can loosen and overheat without the right repair method.
- Fuse boxes and cloth-insulated cable often come with the above.
Full rewire or partial?
A full rewire replaces every circuit and usually the panel. A partial rewire tackles the riskiest parts first: kitchen, bathrooms, laundry and anything still on knob-and-tube. Your electrician will inspect and tell you which circuits matter most.
Where a full rewire isn’t possible yet, code allows GFCI protection on ungrounded outlets, labelled accordingly. That is a safety step, not a replacement for a ground.
Plaster walls
Good electricians rewire old houses by fishing new cable through walls, floors and attics, with small openings rather than open walls. Ask who handles patching and painting afterwards.
Insurance and selling
Many insurers ask about knob-and-tube and fuse boxes, and inspectors flag them when you sell. A rewire with a permit and a passed inspection gives you paperwork to show.