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Knob and Tube Replacement Wiring


Knob & tube wiring was one of the first kinds of standardized wiring for buildings. It was used mainly between the 1880’s and 1930’s, which makes it one of the oldest forms of electrical wiring. If your home was built before the 1930’s, it likely had knob and tube wiring at some point.

If your home still has knob and tube wiring, you most likely need to have it replaced. At WireOne, our professional Des Moines Electrician can inspect your home’s electrical system and help you determine whether or not you need replace all or part of your home’s wiring, or if you need any repairs.

Knob and Tube Wiring Facts

Some of the safer aspects of knob and tube wiring include:

  • Wires were suspended with porcelain knobs, which can help to dissipate heat.
  • Porcelain tubes added additional protection where it passed through wood.
  • Unless they were near a connection to a box or fixture, hot and neutral wire were usually kept around three inches apart. Where hot and neutral wires connected, they had an additional protective woven sleeve.
  • In some ways, knob and tube wiring is actually superior to modern wiring methods when it’s correctly installed. However, unfortunately, it doesn’t often stay completely intact for long periods of time, and if your wiring was installed nearly a century ago, it most likely has some serious problems. So while your knob and tube wiring used to be very acceptable, if it’s still installed in your Des Moines area home, it can easily cause some serious issues.

The two main reasons that knob and tube wiring is considered unacceptable and often unsafe by modern standards are:

  • Knob and tube wiring does not incorporate a ground conductor, which can be extremely dangerous.
  • Switches were often placed on the neutral wire, which means that they would turn off a circuit, but not turn off the electrical current, which can lead to house fires.

Why Replace it if its Working Fine?

If you have knob & tube wiring in your Des Moines home, it could seem to be working fine right up until the point when something goes drastically wrong. There’s no way of knowing when that might occur, or what kind of hazard it will be.

One of the main reasons knob and tube wiring needs to be replaced is that after being in your home for several years, different people—and not all of them professional electricians—have most likely made improper, unsafe alteration to the wiring. One of the unfortunate things about electrical wiring is that it can operate even when it’s improperly installed, which often creates seriously dangerous circumstances.

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If you’re interested in learning more about your residential electrical wiring or any of our other electrical services, our team is standing by and ready to serve you, 24 hours-a-day, 7 days-a-week.

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