How to Replace Knob-and-Tube Wiring in Your Home

If you’ve spotted knob-and-tube wiring, which will look like black cables wrapped around white or gray knobs or posts and running through tubes of the same color, you’re likely in your basement, as this is where the most exposed wires lay. This typically means most of the home contains knob-and-tube wiring. While it’s visible, do not touch the wiring to inspect it.

Instead, you should shut off the breaker to these areas where the exposed wiring is and look from a safe distance for any noticeable damage. This damage would include cracks along the knobs and tubes of the wiring. Any exposed wiring is another sign of damage. The fabric insulation covering the wires may also be frayed or disintegrating.

Beyond damage to actual wiring, you should also check that there is no insulation near the wiring. If there is insulation around the wiring, do not turn on the breaker in these areas until you call a local electrician.

K&T wiring surrounded by insulation is one of the biggest fire hazards to have in your home. Insulation causes the wiring to heat up too much, which can cause it to catch fire.

Knob-and-tube wiring came to popularity when the highest electricity consumption in the household came from a radio. So the electrical panels for knob-and-tube wiring are typically 60 amps, whereas most electrical systems in today’s homes are at least 100 amps. That’s because the appliances and devices we use today consume much more electricity and require an electrical system capable of supporting these needs. 

The outlets connected to this wiring can’t necessarily handle the electricity pull needed for items such as computers, appliances, heating and cooling, and large TVs. Small items such as a lamp, alarm clock, or vacuum cleaner might not have the same problem. This strain and potential for shorting and overheating makes replacing your knob-and-tube wiring an urgent matter.

If it’s not possible to unplug all of these items, try to spread out outlet usage and limit their usage to two electronics at a time. You may still want to use surge protectors, but apply the same principle of limiting it to two electronics at a time.

Please note that doing electrical work yourself, including removing the existing wiring, is not advised unless you are a licensed electrician. Working on any electrical system without proper training can lead to damaging your home and even injury or death. The typical steps for removing the existing knob-and-tube wiring are as follows.

1. The electrician would use a voltage meter or voltmeter to check the lines and confirm that the power is indeed shut off. Never check wires by hand or by touching wires together. If the voltmeter does not stay lit or show indications of being electrified, then the line should be dead.

2. Next, an electrician would begin at the electrical panel and cut the wiring with wire or bolt cutters that are made for cutting this wire gauge. Coming to a porcelain knob, the electrician will cut on either side of it and continue on.

3. Once the wire is cut and removed, an electrician will remove the knobs with either a hammer, prybar, or screwdriver, depending on how the items are fastened to the wood framing, taking care to avoid shattering the porcelain.

4. When the electrician reaches a tube, they pull the wire through the tube. Depending on the electrician’s recommendations, they may remove the tubes or leave them in place.

Before you take any steps on your own to directly test or work on your knob-and-tube wiring, it’s highly recommended to call in a nearby electrician for a professional inspection and guidance on possible next steps for rewiring your house. They’ll look into the severity of the problem and talk about the methods of changing the wiring to a modern standard. 

Because this is a large and costly project, you may only want to replace K&T wiring in certain areas of the home at first. The major areas you should focus on include the bathroom, kitchen, and laundry rooms. These areas have high amounts of water running through them, increasing the potential for electrical shocks and fires.

Other areas like the living room and bedroom may be able to forgo the upgrade, so long as the electrician deems them safe. Protecting yourself and the people in your home as well as your investment in your home will be well worth the call to an electrician.