Knob-and-tube wiring (often abbreviated K&T) was the standard residential electrical method in the United States from roughly 1880 to the 1940s. It is still found in many NYC pre-war homes — Brooklyn brownstones, Queens single-family, Bronx multi-families, Manhattan townhouses, and older Nassau County homes. If you have it, you almost certainly need to replace it.
The reason K&T needs to be removed: it was designed for a different era. The original installations had no ground wire (a major safety issue with modern appliances), the rubber insulation has dried out and cracked over 80-100 years of service, and the system can't safely handle modern electrical loads. Most insurance companies now refuse to insure a home with active knob-and-tube wiring, or they charge significantly higher premiums until it's removed.
Common signs you have knob-and-tube: porcelain "knobs" and ceramic "tubes" visible in your basement or attic where wires run through joists, fabric-wrapped or rubber-insulated wiring (rather than modern plastic-jacketed Romex), two-prong outlets throughout the home (no ground), and home built before 1950 without a documented full rewire.
We do whole-home K&T removal and rewiring as one of our specialty services. The process: full home survey to identify every K&T circuit, NYC Department of Buildings permit, room-by-room rewiring (we work to minimize wall and ceiling damage — most cases are wire fishing through existing walls rather than opening them), upgrade of any associated panel/outlets/switches, and final DOB inspection.
Pricing varies enormously depending on home size and how much existing wiring is reachable through accessible spaces vs. requires opening walls. A typical Brooklyn or Queens single-family rewire runs $8,000-$25,000 depending on size. A larger brownstone or multi-family can run $30,000+. We provide detailed written estimates after a free in-home survey.
Common timing: customers do K&T removal during other major work — kitchen or bath renovation, full home renovation, pre-sale to make the home more marketable, or after an insurance company refuses to renew. We coordinate with general contractors regularly.
Three generations of our family have done this work. We know NYC pre-war housing inside and out. Free estimates: (718) 525-8200.