Updating Knob and Tube Wiring

If you are doing some kitchen remodeling in a pre-1950's house that has not been previously remodeled, you will most likely have Knob and Tube Wiring. This is an obsolete form of wiring. Though it is not inherently dangerous, it is often considered hazardous, and you should seriously consider replacing it. Local codes might even require it once you open up the walls. Of course, you should always have electrical work done by a licensed electrical contractor.

Knob and Tube (K&T) wiring is insulated copper wire which passes through holes drilled in studs. The wires are protected from chafing by porcelain tubes. Periodically, the wires are supported by and passed through porcelain knobs that are nailed down and keep the wire suspended. These are single copper wires so current passes through in one direction, the hot wire, and returns through a separate neutral wire. There is no ground wire.

Knob and Tube Wiring

During the first half of the twentieth century, homes were wired with electricity primarily for electric lights. The only appliances found in most homes consisted of small appliances such as tea kettles or toasters. Therefore as refrigerators, televisions, and other electrical devices came along with their increasing electrical amperage demands homes often received a patchwork of modifications to their K&T wiring as each new device was added. Many of these modifications were improperly done, resulting in shock and fire hazards caused by reverse polarity, crossed neutrals, and overloaded circuits.

Knob and tube wires are insulated with a rubberized cloth or fiber that can deteriorate over time. Even if your local code does not require replacement, it is a very good idea to do so because of the age of the system, the possibility of deterioration, and the fact that grounded appliances with 3 prong cords are not designed to operate on K&T wiring. There are also insurance companies that will refuse to provide insurance for a home with knob and tube wiring.

How can you tell if you have knob and tube wiring in your kitchen? If your wall switches are push button, that would be one indication of K&T wiring. If your receptacles do not accomodate a grounded plug, that is another indication. However, there have been modifications that have updated electrical receptacles, switches, and even junction boxes but left the K&T wiring in place inside the walls. Sometimes, the only way to know for sure is to open up a wall or check in the attic.

How much will all of this cost? It depends on whether just the kitchen needs to be rewired or the entire house. It also depends on what modifications might have already been done, and if they were done properly. An entire house could cost as much as $8-10 thousand dollars. If just the kitchen needs to be rewired you must consider that some wiring expense would be incurred in your kitchen remodel anyway, so an additional $2000 or so might not be out of line to replace some old K&T wiring.

The GOOD news is knowing that you have done what is necessary to protect your house for your safety and enjoyment, and preserve the resale value as well. As a reminder, make sure that your work complies with all applicable codes and is done by a licensed and bonded electrical contractor.

Now that you've got your wiring issues resolved, be sure to contact the professionals at Universal Appliance and Kitchen Center to save money on your appliance purchases.

Universal Appliance and Kitchen Center
12025 Ventura Blvd. Ste B-105
Studio City, CA 91604
PH 877 696-2987
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