Wisconsin has some of the oldest housing in the Midwest. Milwaukee bungalows, Madison foursquares, farmhouses across the Driftless and Victorian homes in every river town share one thing: wiring that may be far older than the paint suggests.
Knob and tube wiring
Installed until roughly the 1940s, knob and tube uses separate hot and neutral wires run through ceramic knobs and tubes. Look in an unfinished basement or attic for single cloth-covered wires on white porcelain supports. It has no ground wire, the insulation becomes brittle with age and it was designed to shed heat into open air, which is why burying it in attic insulation is a recognized fire hazard.
Aluminum branch wiring
Between about 1965 and 1975 many homes were wired with aluminum instead of copper. Aluminum expands and contracts more, loosens at screw terminals and oxidizes, and the resulting poor connections overheat. Look for "AL" or "ALUMINUM" printed on cable jackets in the basement or attic. Warm cover plates and flickering lights are warning signs.
Why it matters
Many insurers will not write or renew a policy on a home with active knob and tube, and some surcharge aluminum. Buyers' inspectors flag both. Beyond the paperwork, both types are simply past the point where they can be trusted with modern loads.
Your options
- Full rewire. Whole house rewiring replaces everything with grounded copper circuits. It is the permanent answer for knob and tube.
- Phased rewire. Start with the highest-risk circuits and continue room by room as budget allows.
- Aluminum remediation. Where a full rewire is not practical, approved connectors can be installed at every outlet, switch and fixture to join aluminum safely to copper.
Start with an electrical inspection so you know exactly what is in the walls. Older fuse boxes often go hand in hand with old wiring, and a panel upgrade is commonly done at the same time.