Here is some basic information about knob and tube:

Knob-and-tube (K&T) wiring was an early standardized method of electrical wiring in buildings, in common use in North America from about 1880 to the 1940s. The system is considered obsolete and can be a safety hazard, although some of the fear associated with it is undeserved.


Facts About Knob and Tube Wiring:

  • Knob and Tube Wiring is not inherently dangerous. The dangers from this system arise from its age, improper modifications, and situations where building insulation envelops the wires.
  • It has no ground wire and thus cannot service any three-pronged appliances

Problems with Knob and Tube Wiring:

  • Unsafe modifications are far more common with K&T wiring than they are with Romex and other modern wiring systems. Part of the reason for this is that K&T is so old that more opportunity has existed for improper modifications.

  • The insulation that envelopes the wiring is a fire hazard.

  • It lacks a grounding conductor. Grounding conductors reduce the chance of electrical fire and damage to sensitive equipment (like computers of really nice televisions) 

 How does Knob and Tube Affect the Potential Homeowner?:

  • Many insurance companies refuse to insure houses that have knob-and-tube wiring due to the risk of fire.  A good idea is to check with your insurance company BEFORE you put the offer in to see what their policies are regarding insuring a home with Knob and Tube.


Advice for those with K&T wiring:


  • Have the system evaluated by a qualified LICENCED electrician. Only an expert can confirm that the system was installed and modified correctly.
  • Do not run an excessive amount of appliances in the home, as this can cause a fire.
  • Where the wiring is brittle or cracked, it should be replaced. Proper maintenance is crucial.
  • K&T wiring should not be used in kitchens, bathrooms, laundry rooms or outdoors. Wiring must be grounded in order to be used safely in these locations.
  • Rewiring a house can take weeks and cost thousands of dollars, but unsafe wiring can cause fires, complicate estate transactions, and make insurers skittish.


REMEMBER! Electricity has become an important element of every home. Electricity can provide: heat, lighting and provides power for all the electronic and gadgets in our homes. Electricity and your home electrical system is dangerous and the best advice is to always contact a Licenced Electrician before working on your own home.

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