Fusion Electric Blog

The Many Dangers of Knob and Tube Wiring

Knob and tube wiring was a popular option in American from 1880 until the latter part of the 1940s. It’s an early style of electrical wiring that’s easy to identify by its ceramic, white, spool-like knobs. It’s still found in a number of older homes and presents several dangers to those who live in them. If you still have this type of wiring in your home, it’s time to call an electrician to have it replaced.

Some of the specific dangers presented by knob and tub wiring can be found here.


Generally speaking, knob and tube wiring ranges from 70 up to 130 years old Even if it’s been working for some time, this old wiring doesn’t have the capacity that’s required for modern homes. If this type of wiring is used for all the modern electronics and devices, it may become overloaded and start a fire. Also, the wiring isn’t as resistant damage to modern wiring. This represents yet another risk of fire to homeowners.

No Ground Wire

Modern three-plug appliances aren’t compatible with knob and tube wiring. Due to this, anything that’s plugged into it is very liable for damage because of voltage surges and fluctuations. This is another fire hazard and can also result in electrical shocks.

Not Good with Moisture

In addition to being located underground, knob and tube wiring isn’t rated for moisture. This results in it being especially dangerous when used in wetter areas, such as outside, bathrooms, and kitchens.

Easily Overlooked

In many cases, knob and tube wiring is buried in insulation and then pushed into contact with building materials and all other types of clutter. Since this type of wiring is made to release heat into the air, this presents another fire hazard. In fact, insurance companies may not provide insurance for buildings that have this wiring because the NEC has stated that knob and tube wiring must stay away from the home’s insulation.

Improper DIY Modifications

When it comes to wiring, the most dangerous issue that is found today is DIY modifications that have been made with knob and tube wiring. Some of this is due to how easy it is to access for splicing purposes. It’s actually very common for people to use Scotch and masking tape, rather than electrical tape, for these DIY connections. What’s even worse, DIY fixes can cause serious problems, the risk of shocks, and the risk of fires.

It May be Time to Contact an Electrician

If you have knob and tube wiring in your home or building, then it is a good idea to contact an electrician right away. They can inspect the issue and make recommendations about what needs to be done to help improve the safety of the home and building. It’s a good idea not to put off this call, as the longer knob and tube wiring is left in place, the more likely it is to cause a fire or another electrical problem.