How to Know if Your House Has Knob & Tube

Indicators

• 1

  Note the age of your home. If it was built after 1950, it is less likely to have knob-and-tube.

• 2

  Check the household for push-button style light switches instead of modern toggle, dial or sliding bar styles. Surface-mounted, porcelain light fixtures with exposed light bulbs and pull chains instead of wall switches are another indicator.

• 3

  Determine whether any outlets have two prongs instead of three. Modern electrical outlets include openings for at least three prongs, sometimes more, one of which is a ground. Two-prong outlets have no ground and were used with knob-and-tube wiring.

• 4

  Locate the load center, which is a fuse box in some homes and a breaker box in others. Load centers are usually large, rectangular metal boxes that are recessed in a wall. If your load center is a fuse box, knob-and-tube wiring may be present. Do not disassemble or remove the fuses and covering inside the box.

Confirmation

• 5

  Put on a pair of electrician’s insulating gloves, which will help protect you from accidental shocks.

• 6

  Access the attic or basement, or open a panel in the ceiling. Many older homes have access panels in closet walls or ceilings. Some are small, hinged doors and others are panels that pop out when you push on them.

• 7

  Shine a flashlight along the ceiling or floor joists.

• 8

  Look for thick, fabric-covered wires and ceramic knobs or tubes that are mounted to the joists. Knobs and tubes are most often white ceramic, and the wiring is black or a dark color. Do not touch the wiring or any parts of the knobs and tubes.