Posted: October 20th, 2009
Many of the homes in Lancaster County are older with great architectural detail and character. However, one of the less attractive historical features, from an insurance perspective, can be the”knob and tube” wiring that is commonly found in homes built prior to the 1930’s. As a result, homebuyers may have trouble finding a Homeowners Insurance carrier that will insure a home with knob and tube wiring.
What is “knob and tube” wiring?
Knob and tube wiring is an electrical wiring method that was commonly installed in buildings between 1880’s to the 1930’s. The system uses porcelain “knobs” to support the wiring and to keep it away from the potentially combustible framework. Ceramic “tubes” are used to run wires through beams, rafters and walls and to prevent the wires from being compressed by wood when the house settles.
Why are insurance companies so cautious about knob and tube wiring?
• General deterioration, since it is 60+ years old
• Knob and tube has no ground wire like modern electrical systems which can be an increased fire hazard
• The original electrical wiring may have had additional branches and outlets improperly installed that may overheat the wiring and disintegrate the insulation protection
• Power demand from modern technology can exceed the original supply design and lead to blown fuses
• Animals love to chew off the insulation protection
• Homeowners install additional thermal insulation in the attic that covers the wiring and suffocates the wiring from the open air needed for cooling
What should a homebuyer do if they are purchasing a home with knob and tube wiring?
• Get your insurance agent involved as soon as possible checking on the situation. Every carrier has different underwriting guidelines and requirements to handle homes with knob and tube wiring. Some carriers may not even insure a home if it has any knob and tube wiring.
• Have a certified electrician inspect the entire electrical system. Not only will this ensure that electrical system meets current code, it will also give a homebuyer the peace of mind that the new house does not have additional fire hazards.
Overall, insurance for a knob and tube home is handled on a case by case and carrier by carrier basis. Find out early what an insurance carrier requires so that you don’t have any surprises prior to closing.
Christopher Vogt, Baron Insurance Group
Address: 20 E High St Manheim, PA 17545
Office Phone: 717-665-2985
Email: chrisv@baroninsurancegroup.com
Twitter: @christophervogt










Active knob and tube wiring is also a road block to energy efficiency upgrades. The BPI (Building Performance Institue) standard calls for it to be removed or disonected prior to insulating those areas.
Good call out, Scott!