An Introduction to Knob and Tube Wiring

Knob and tube wiring was commonly used in homes built in the early 1900s up until the 1940s. This type of wiring consists of individual wires that are run through ceramic knobs and tubes, usually in between walls and ceilings. While knob and tube wiring was safe when it was first installed, it often does not meet today's electrical code requirements and can pose a safety hazard. However, many homeowners with vintage homes want to preserve the original knob and tube wiring for historical accuracy. This article will explore how I rewired my 1920s home while keeping the existing knob and tube wiring intact.

Reasons to Rewire With New Wiring

There are several important reasons to rewire a home with new wiring while preserving the original knob and tube wiring:

Pre-Rewire Inspection and Planning

Before starting any rewiring project, it is important to do thorough inspection and planning:

Running New Wiring Next to Old Knob and Tube

The easiest way to rewire while preserving knob and tube is to run the new wiring alongside the old. Here is how to do it:

Repurposing Existing Knob and Tube Wiring

For certain short wiring runs, you may be able to carefully remove the old knob and tube wiring and install new wiring in its place:

Matching Old and New Wiring Aesthetically

To create a seamless look, choose new wiring components that match old ones in style:

Maintaining Safety With Old Wiring

It is crucial to maintain safety when old wiring remains in place:

When to Remove Knob and Tube Entirely

In some cases, completely removing all old wiring may be necessary:


With careful planning and execution, rewiring a 1920s home without harming original knob and tube wiring is definitely achievable. The most effective approach is running new wiring alongside the old, taking advantage of accessible spaces like basements and attics when possible. Maintaining safety with the existing wiring should always be the top priority. With some upgrades to electrical capacity and safety, while keeping beloved vintage wiring aesthetics intact, you can give your historical home the best of both worlds.