Knob-and-Tube Wiring

Vintage knob and tube wiring

Was your home built before 1950? There’s a good chance you have knob-and-tube (K&T) wiring. This early method of wiring was most common in North America from around the 1880s to the 1940s. While it’s not necessarily dangerous, the system has been considered obsolete for decades and, in some cases, can pose a safety hazard.

What is Knob-and-Tube Wiring?

K&T wiring is self-explanatory. It consists of wiring protected by rubber and porcelain or ceramic tubes for support when passing through wood framing. The ceramic knobs are nailed or screwed to wooden structural components and support the tubes.

Is K&T Wiring Safe?

It can be. This is almost impossible to answer until inspecting the existing system. While your K&T system may be in great shape, there’s an equal chance it needs to be replaced immediately. Why?

  • Inefficient Electrical Supply. K&T simply wasn’t designed to power modern-day homes, and for good reason. There was no way to foresee the amount of electricity we currently use daily. Back then, the system powered toasters, coffee percolators, clothes irons and light bulbs (and later refrigerators and small black and white TVs). Demand has increased significantly over time.
  • Damage and/or Poor Connections. Over the years, previous owners may have added onto the existing systems. Often, these connections were made by splicing wires together and may be dangerous. Essentially, the age of the system increases the likelihood that improper modifications were made.
  • Age and Brittleness. Time takes its toll on all things, and K&T wiring systems are no exception. The wires back then were insulated with rubber, which can become brittle and deteriorate. Conductors can also stretch and sag over time, and old, damaged wiring can be a fire hazard if installed near insulation.
  • No Ground Wiring. Modern wiring systems consist of black, white and ground wires bundled together and encased in plastic. The K&T system has separate tubing for black and white wires, and no ground wire exists. This is obviously a safety hazard, especially in areas close to water.
  • Uninsurable? Some insurance companies will not insure homes that use K&T wiring, no matter its condition. Other companies do not mind or will only insure the home if a licensed electrician gives it a passing grade.

What Should I Do if I Have K&T Wiring?

First, don’t panic. No codes or regulations specifically require K&T wiring to be removed from your home. Many homeowners replace room-by-room as they remodel or update the home. Your K&T wiring may be completely safe, but considering its age and possible safety concerns, we highly recommend having it inspected and evaluated annually.

Call the Experts!

Don’t let fear keep you up at night but be aware that your K&T wiring potentially places your home and its inhabitants at risk. You owe it to yourself and your loved ones to have it inspected, at the very least. Give the pros at Milton Electric a call and let us give you an expert analysis. We’re here to help!