The National Electrical Code decreed in 1987 that it would not permit insulation contact with knob and tube wiring systems, though some jurisdictions still allow it if the wiring is in good condition. You might notice parallel strands of wire running to and fro across your attic floor or in the rafters.

Can you insulate around knob and tube?

K&T wiring is designed to dissipate heat into free air, and insulation will disturb this process. Insulation around K&T wires will cause heat to build up, and this creates a fire hazard. The 2008 National Electrical Code (NEC) requires that this wiring system not be covered by insulation.

Can you put blown in insulation over knob and tube wiring?

Currently the United States NEC forbids use of loose, blown-in, or expanding foam insulation over K&T wiring. This is because K&T is designed to let heat dissipate to the surrounding air.

Where should you not put insulation?

Do not use fiberglass insulation in basements. Fiberglass traps mold well and basements are notorious for having moisture problems. Instead, use closed cell foam board and spray for basement installation. Never place insulation close to water heaters, oil burners or anything hot.

How do you protect knob and tube wiring from insulation?

Insulating Knob and Wire System

Any type of insulation is possible if the existing knob and tube wiring is protected by a box large enough to provide 3 inches clearance around the conductors.

Can fiberglass insulation touch electrical wires?

It is perfectly safe for household insulation to touch wires provided the wires or cables are electrically insulated. There also are techniques to make insulation fit better around wires. However, under no circumstances should thermal insulation make contact with live uninsulated wires and cables.

How many house fires are caused by knob and tube wiring?

In this article, we dispel the myths of wiring and uncover the truth about outdated knob and tube wiring that contributes to more than 28,000 fatal house fires per year.

Is knob and tube safe?

Knob and tube wiring is not inherently unsafe. Rather, it can become hazardous due to age, improper modifications and situations where building insulation envelops its wires. Because it has no grounding conductor, knob and tube wiring is also more vulnerable to fires than modern electrical wiring.

Can you touch knob and tube wiring?

The best way to handle knob and tube wiring is to get it replaced and updated with new, safe electrical in your home. DO NOT attempt to DIY any knob and tube wiring fixes or installs. Knob and tube electrical systems are at their highest risk of failure and fires when people attempt to fix it themselves.

Does knob and tube wiring meet code?

The NECĀ® requires that attics and walls with this type of wiring not be insulated in such a manner that the insulation envelopes the wire. However, the California Electrical Code has amended section 324-4 to allow insulation in contact with knob & tube provided 6 conditions are met.

Can you leave knob and tube wiring in the walls?

A: All visible knob and tube wiring will need to be removed in spaces like unfinished basements and attics. Basically, anywhere the knob and tube wiring is visible it must be completely removed. In walls and ceilings where the KT wire is concealed, it does not need to be removed, just deactivated.

What year did they stop using knob and tube wiring?


What is Knob and Tube Wiring? Knob and Tube wiring is the wiring technique that was most commonly used in United States homes from 1880 to 1940, according to the International Association of Certified Home Inspectors.

Can you get a mortgage on a house with knob and tube wiring?

Yes, you can get approved for a home with Knob and Tube wiring. The underwriting guidelines for all of the major mortgage agencies (Fannie Mae, Freddie Mac, FHA, VA, and USDA) all allow for Knob and Tube wiring as long as the system is deemed to be safe, functional, and typical for the area.

Can insulation catch on fire?

Can it burn? Yes, it actually can! Although most insulation materials are extremely fireproof, a myriad of issues can cause your insulation to burn. Fiberglass insulation is made of glass combined with plastic polymers and is naturally fire-resistant.

Can you put insulation around electrical outlets?

Quote from Youtube video: Take a marker make them up line where the top and the bottom of the electrical. Box are. Put the insulation on the ground compress it and put this line exactly on the edge of the insulation.

Can you put insulation around wires?

Quote from the video:
Quote from Youtube video: It put it over the top and drape. It down when you come into account with the wiring that's run on the outside.

Can wiring go behind insulation?

Wiring should be installed before any insulation. When building a home, everything needs to be done in the correct order. For instance, after the framing is complete and the exterior walls have been put up, you need to consider the inside of the wall cavities before you drywall the interior.

Can you put expanding foam around wires?

You have to consider if using foam is safe if you have anything routed inside the cavity, such as electrical wiring. So, if you were wondering whether expanding foam damages wiring the answer is yes. Expanding spray foam without carefully planning can damage electrical wiring.

How do you install insulation around an outlet?

Another simple step for better outlet insulation is to apply foam or caulk into the gap around the flush-mounted box, behind electrical cover plates. After foam hardens, you can slice off the excess with a serrated knife. To seal wall boxes, first seal the cable intrusions and then the gap around the box.