Though old Knob and Tube may have been ‘working’ in your home for a while, today’s homes require much more electricity than 1940's homes, before refrigeration, TVs, and phone chargers and smart home devices became standard electrical use in a home. Thus knob-and-tube is frequently overloaded, posing a fire hazard. Also the casing around the wire is old and vary brittle that make it easy to breakdown, expose wires over time, and in some cases, corroding copper wire due to insulation additives. Less resistant to damage than modern wiring, as components breakdown, stretch and sag over time, Knob and Tube can also suffer unintentional contact with surrounding materials, resulting in serious fire and electrical hazards.
It’s Lack of Ground Wire
Incompatible with 3-prong appliances Knob and tube lacks grounding, providing only a hot and neutral wire. This puts electronics at increased risk of damage as voltage fluctuations and surges have nowhere to go, putting your valuables, family and home at risk of shock and fire.
It’s Incompatibility with Moisture
Already underground, knob-and-tube is not rated for moisture and exceedingly dangerous when used in wet locals such as kitchens, bathrooms, laundry and utility rooms, and outdoors.
It’s Tendency to Be Overlooked
Knob-and-tube is frequently buried with insulation and pushed into contact with building materials and storage clutter. Designed to dissipated heat freely into the air, this results in a fire hazard. National Electric Code (NEC) requires Knob&Tube not be covered by insulation, or used in the hollow spaces of walls, ceilings, or attics where insulating materials can come into contact with the wiring and conductors. Just one of the many reasons most insurance companies refuse to cover houses with knob-and-tube.
The Frequency of Improper Modifications with Knob and Tube
Improper and unsafe DIY modifications are much more frequently found with knob-and-tube wiring than with modern wiring systems. Part of this is increased opportunity due to its age, as well as due to ease-of-access for splicing. Amateur modifications to Knob and Tube are so common, connections made with masking or Scotch tape (instead of electrical tape) are frequently encountered. Worse, the insufficiently trained frequently install fuses with an amperage too high for the wiring of Knob and Tube (to pair them with newer electronic appliances and devices), overloading and resulting in damage to wires, which over time breakdown, greatly increasing fire risk.
Live in an older home? Don’t assume safety. Schedule an electrical safety inspection with Mr. Electric today.
This blog is made available by Omega Electric for educational purposes only to give the reader general information and a general understanding on the specific subject above. The blog should not be used as a substitute for a licensed electrical professional in your state or region. Check with city and state laws before performing any household project.