you’re paying off a legacy—knob and tube wiring everywhere, until it’s too risky to ignore

Tue, 05 May 2026 16:34:17 +0000

You’re Paying Off a Legacy: Knob and Tube Wiring Everywhere—Until It’s Too Risky to Ignore If you own an older home—say built before the 1950s—chances are, hidden behind the walls, beneath the floors, and behind doorplates, you’re walking through a legacy of knob and tube wiring. Once considered state-of-the-art in its time, this outdated electrical system now poses significant safety risks—and opening the walls to pay it off is often the smart, necessary step. ### What Is Knob and Tube Wiring? Knob and tube (K&T) wiring was the dominant electrical system in homes across North America from the late 1800s through the mid-1900s. It consists of individual insulated copper conductors run through ceramic knobs and tubes, suspended in wall cavities or runs—no conduit, no sheathing, and minimal grounding. While innovative when first introduced, K&T lacks modern safety features such as circuit breakers, grounded circuits, and robust insulation.