Rewiring a home can be an intimidating task, but with the right knowledge and preparation, it is very doable as a DIY project. While modern electrical methods make rewiring easier and safer, there are some obsolete and forgotten techniques that the daring DIYer can employ for a unique rewiring project.

In this article, I will provide an in-depth look at obsolete electrical wiring methods that have been replaced by more modern techniques. We will cover materials, safety considerations, step-by-step installation, and pros and cons of using these outdated wiring methods to rewire your home.

Knob and Tube Wiring

Knob and tube (K&T) wiring was commonly installed in homes built prior to the 1940s. This wiring method utilizes insulated copper conductors that are suspended between ceramic knobs and through porcelain tubes attached to framing members.

While obsolete, K&T can still be safe if undisturbed and unmodified. However, it does not meet modern electrical codes and has some drawbacks:

If attempting to reuse K&T wiring, extreme care must be taken to avoid overloading circuits, provide GFCI protection, and prevent hazards with insulation, splices, and clearances. Upgrading the wiring is recommended whenever possible.

Materials Needed

To properly install new K&T wiring, you will need:

Safety Tips

When working with open conductive K&T wiring, exercise extreme care:

Installation Steps

Rewiring a room with new K&T wiring involves:

  1. Turn off power at the main breaker panel and verify it is off.

  2. Remove existing wiring if present.

  3. Map out wiring runs from the panel to outlets and fixtures.

  4. Mount ceramic knobs at appropriate intervals.

  5. Run the new insulated wires through porcelain tubes where passing through framing.

  6. Twist wires together with wire nuts at junction boxes. Connect to devices.

  7. Attach wires to ceramic knobs to support the run. Keep spacing as required by code.

  8. Label circuits clearly in the panel and junction boxes.

  9. Carefully re-energize the main power and test operation of all lighting/outlets.

Always follow electrical codes and best practices for safety. Carefully plan the wiring runs and do not overload circuits.

Gas Pipe and Tube Wiring

From the 1890s until the 1920s, a peculiar obsolete wiring method used existing gas piping to provide the wiring runs throughout a house. Insulated wires were pulled through the gas pipes, which provided protection and a ready-made conduit system.

This method has some advantages but also serious safety concerns:

- Utilizes existing piping runs throughout home.
- Protective enclosure for wiring.

- Extreme fire and shock hazard if piping is energized.
- Wiring is difficult to inspect inside pipes.
- Very small conductors must be used, limiting capacity.

While evocative of an older era, rewiring or modifying gas pipe wiring is not recommended. Modern electrical conduit or armored cable is a much safer approach.

Armored Cable Wiring

Armored cable (AC) consists of insulated wires wrapped in a spiral metal casing. The metal armor provides protection and acts as the ground path.

AC wiring was an early form of flexible wiring for lights and outlets. Two main types were used:

AC wiring has largely been replaced by modern NM cable (Romex) which is cheaper and easier to install. However, reproduction armored cable is available.

Pros and Cons of AC Wiring


- Heavier and harder to install than Romex
- Can be unsafe if modified incorrectly
- Old BX may contain lead or asbestos

If reusing original vintage armored cable, have it professionally inspected. New repro AC cable can be installed by a competent DIYer following standard wiring practices.


While rewiring a home using obsolete methods like knob-and-tube can be an interesting novelty, it requires extreme care and diligence. Modern electrical wiring is far safer and offers greater capacity and flexibility.

Always consult local inspectors and ensure any work meets the National Electrical Code. For a safe rewiring project, hire a licensed electrician whenever possible. By understanding obsolete wiring methods, you can better evaluate your home’s existing wiring and electrical safety hazards.