5 Things to Do if You Have Knob-and-Tube Wiring in Your Home

Matt Marandola
Written by Matt Marandola
Updated September 23, 2021
An electrician checking wiring in a house
Halfpoint Images/Moment via Getty Images

These five tips can help you determine your next steps if you find knob-and-tube wiring in your home

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While not common in houses built after 1950, those built before and a little after may have knob-and-tube wiring. Knob-and-tube wiring, otherwise known as K&T wiring, doesn’t have a grounding wire, so it poses an increased chance of shocks and fires. If you’re concerned there is knob-and-tube wiring in your house, here are five things you’ll want to do to handle the situation.

1. Determine If There’s Damage Near the Wiring

If you’ve spotted K&T wiring, which will look like black cables wrapped around white or gray tubes, 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.

2. Ensure There’s No Insulation Near the K&T Wiring

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 an electrician.

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

3. Unplug Most Items Connected to the K&T Wiring If Possible

K&T wiring came to popularity when the highest electricity consumption in the household came from a radio. The outlets connected to this wiring can’t necessarily handle the electricity pull needed for items such as desktops, large TVs, and video game consoles. Small items such as a lamp, alarm clock, or vacuum cleaner might not have the same problem.

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.

4. Call an Electrician ASAP

A worker on a ladder checking electricity wiring in a construction site
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Once you’ve taken these precautions, it’s time to call in a local electrician. They’ll look into the severity of the problem and talk about the methods of changing the wiring to a modern standard. 

The cost to replace wiring around the house can range depending on how big the home is and how much wiring they’ll need to switch out, but it typically ranges from $2 to $4 per square foot. Because of the safety risks associated with K&T wiring, it’s almost always worth it to upgrade your wiring, and you’re going to see a decently high ROI.

5. Determine the Best Course of Action

Because this is a large 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, leading to 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.

DIY vs. Hiring a Pro to Install New Wiring

You should never, under any circumstances, handle knob-and-tube wiring on your own. Replacing K&T wiring is one project that can quickly lead to serious injury and fire if not handled correctly. Instead, hire a licensed electrician who can inspect the wiring and how it will hold up over the coming years.

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