Introduction
Rewiring a home can be an intimidating task, but with proper research, safety precautions, and attention to detail, it is possible for a dedicated DIYer to take on this project. In this guide, I will walk through some of the obscure wiring methods used in old homes and give tips on how to safely update the wiring in your vintage home.
I must stress up front that working with electricity carries inherent dangers if not done correctly. Any home electrical project should only be undertaken with proper precautions, research, and ideally with permits and inspections from your local building department. If you are uncomfortable working with electricity, I strongly recommend hiring a licensed electrician.
Know Your Home's Electrical History
Before beginning any rewiring project, it's important to understand the type of wiring that exists in your home currently.
Knob and Tube Wiring
One of the earliest and most dangerous forms of wiring, knob and tube consists of individual wires run through ceramic knobs and tubes, often without a ground wire. This type of wiring was phased out in the 1930s. If your home contains original knob and tube wiring, I strongly recommend hiring an electrician to replace it, as it can be unsafe.
Armored Cable (BX)
BX cable was an early form of flexible metal clad wiring that provided some protection for the inner insulated wires. It was used from the 1920s-1950s. BX can be safe if in good condition, but the metal sheathing can become brittle over time. Inspect carefully before reusing.
Cloth-Covered Wiring
Early wiring often used cloth insulation wrapped around individual wires. This provides little fire resistance. Any original cloth wiring should be replaced.
Other Obsolete Wiring
Some other early wiring types like asphalt-coated wire and rubber-insulated wire are also potentially unsafe. Know what you have before proceeding.
Safety Gear
Electrical work requires proper safety equipment including:
- Insulated tools - Never use metal tools which could contact live wires
- Voltage tester - Test wires before touching to be sure power is off
- Safety goggles & gloves - Protect your eyes and hands
- Face mask - Avoid breathing dust or fibers from old insulation
I also recommend having someone present in case an emergency arises.
Turn Off Power
The most important safety step is to turn off power to the circuits you'll be working on. Turn off the main breaker or pull the main fuse to be safe. Double check with a voltage tester that the wires are de-energized.
Remove Old Wiring
Once the power is off, you can remove any outdated, hazardous wiring. Knob and tube wiring often has insulation that contains asbestos, so take precautions against breathing any dust.
Be careful to note any wiring connections before removing old wires. Take photos or draw diagrams to use for reference when rewiring.
Properly dispose of old wires, either at a hazardous waste facility or sealed in bags for regular trash pickup, depending on your municipality's rules.
Install New Wiring
When installing new wiring, be sure to follow local building codes. Use the proper wire gauge for the amperage on the circuit. Here are a few tips:
- Use only copper wiring, not aluminum
- Run wires through non-metallic sheathed cable
- Use wire nuts or terminal blocks for connections
- Include a ground wire on all circuits
- Stagger connections across multiple outlets on long runs
- Use junction boxes to house connections
Avoid kinking wires and secure cables properly. Leave plenty of extra wire at connection points.
Inspect and Test
Before turning the power back on, have an electrician inspect your work and fix any issues. They can also perform important safety tests:
- Continuity test - Confirms proper end-to-end connections
- Polarity test - Verifies hot and neutral wires are correct
- Ground test - Checks for appropriate grounding
- Insulation test - Makes sure there are no bare wires touching
Only once everything checks out should you restore power. Turn it back on at the main breaker or fuse panel and test each circuit before completely finishing the rewiring project.
Conclusion
While rewiring an older home is ambitious, it can restore your electrical system to modern safety standards. But this is not a project to undertake lightly. Only do so with the proper safety gear, research, permitting, and if you feel confident in your electrical skills. When in doubt, hire a professional electrician to avoid deadly mistakes. Stay safe!