Knob & Tube Wiring Replacement

What Is Knob-and-Tube Wiring?

Knob-and-tube wiring (K&T) is an electrical wiring system that was commonly used in residential and commercial buildings from about 1880 to the 1930s. It consisted of single-insulated copper wires passing through joists and studs via porcelain insulating tubes, and supported by porcelain knobs.

What Are the Hazards Associated with Knob-and-Tube Wiring?

• Simply put, age! K&T wiring (and similar ungrounded wiring) is old, and the copper conductors deteriorate over time. The substandard cloth insulation degrades, which can lead to short circuits and fires.

• Knob-and-tube wiring is outdated. It was not designed to handle the electrical demands of modern homes and buildings. Because of its limited capacity, K&T wiring can become overloaded and may not provide enough power for appliances and other electrical devices, in turn leading to voltage drops, overheating, and other problems.

• It’s difficult to update. Knob-and-tube wiring is not compatible with modern electrical devices and appliances, which causes difficulty when updating the electrical system in a building. The cotton insulation crumbles when touched, necessitating replacement of that cable from its source. Several dangerous and illegal “solutions” exist; one common “shortcut” is junctioning the old wiring to modern and hiding the splice behind the wall. This is against electrical code. If you are having K&T wiring updated but not replaced, ensure that your electrician is NOT using this or similar methods! 

• There is no grounding. K&T wiring does not have a safety grounding conductor, which can increase the risk of electrocution and damage to electrical appliances.

• Safety codes. K&T wiring does not meet modern safety codes and standards. Ignoring these puts homeowners and building occupants at risk.

We strongly recommended that K&T wiring be replaced with modern wiring to ensure the safety of a building and its electrical system. An electrician should assess the condition of K&T wiring and determine if it needs to be replaced.

Why Should I Replace My Knob-and Tube Wiring? 

There are several benefits of replacing K&T wiring. Insurance is a big one - most home insurance companies will not cover fires caused by knob-and-tube wiring. While you might be able to get insurance on a home with knob and tube wiring, your options will be limited, and the company will charge a premium to inspect your home before deciding to offer coverage or not. Is it worth it to pay so much money for less-than-ideal, risky wiring? Replacing your outdated knob-and-tube wiring brings your home up to modern safety standards. And of course, there’s a lot to be said for peace of mind!

Interested in further reading? This article offers more insight into K&T wiring, as well as a helpful list of insurance companies and their recent (December 2022) policies.  Knob and tube wiring concerns: safety and insurance 

How Reamco Electric Does It

At ReamCo Electric, we offer several options for protecting you from ungrounded knob-and-tube wiring. We often use a combination of methods when rewiring a house. 

1. Installing modern cables with ground wire to connect the ungrounded devices.

2. Running a ground wire to accessible receptacles and fixtures. 

3. Putting GFCI protection on the ungrounded circuits by means of GFCI breakers and/or GFCI receptacles. A GFCI breaker or receptacle measures the power going through the hot and neutral line. If it senses an imbalanced load, such as a short circuit or any current leakage, it will trip and shut the circuit off.