Introduction
Rewiring a home can seem like a daunting task, but it doesn't have to be if you use some of the obsolete and forgotten methods from decades past. While modern electrical codes and safety standards have made many historical wiring techniques illegal today, learning about these archaic DIY electrical methods can give you inspiration and knowledge to take on your own rewiring project.
In this comprehensive guide, I'll walk through some of the most notable obsolete wiring methods used in old houses. While not advisable to replicate today, understanding the evolution of electrical systems provides context for working onolder homes. I'll also share tips for how to approach a rewiring project using modern materials and best practices.
So if you're a homeowner looking to rewire on a budget, or just fascinated by antique electrical systems, read on!
Knob and Tube Wiring
The earliest standardized method of wiring homes in the late 19th and early 20th centuries was called knob and tube. This consisted of:
- ** porcelain knobs** attached to joists or rafters to hold the wiring up and away from wood
- Porcelain tubes to protect wires through joist and stud holes
- Rubber insulated wiring running between the knobs and tubes
While revolutionary for its time, knob and tube lacks many crucial safety features. It has no ground wire and flammable insulation. Replacing knob and tube wiring is recommended today.
However, you may be able to reuse the existing knob and tube pathways through walls and ceilings when rewiring. Fishing new wires through the old tubes and knockout holes can save a lot of time and damage to your home.
Armored Cable (BX)
Armored cable, sometimes called BX, was an early form of flexible metal jacketed wiring. It emerged in the 1920s as an alternative to knob and tube that was more affordable than conduit.
BX cable consists of:
- An outer flexible metal sheath, usually steel
- Insulated wires inside
The metal sheathing grounds the wiring and resists damage. BX was considered very modern and convenient for snaking wiring through existing homes. It's still legal in some circumstances today.
When rewiring, you may be able to pull new wires through existing BX conduit. The old armored cables make handy pathways to fish wires between floors and through cramped spaces.
Cloth Covered Wiring
From about 1920-1950, a very common wiring method was cloth covered cables. These consisted of solid copper wires wrapped in cloth tape insulation.
While handy for retrofits, the cloth insulation was flammable and deteriorated over time. It emitted toxic fumes when it burned. Aluminum versions were even more fire prone.
If rewiring a home with original cloth wiring, I recommend fully replacing all the existing cables. The insulation is too hazardous to reuse.
Other Notable Obsolete Wiring
Here are a few more important obsolete wiring methods you might encounter in older homes:
- Lead sheathed cables - Used from the 1930s-1960s, prone to fires
- Rubber insulated wiring - Flammable insulation used until the 1960s
- Aluminum wiring - Higher resistance than copper, can be fire risk
My recommendation is to completely replace any old aluminum or rubber insulated wires in your home. Consult an electrician before reusing any unusual old cables or wiring materials.
Tips for Rewiring Your Home
Rewiring with modern wiring methods can make your home much safer. Here are some tips:
- Use copper wiring with up-to-code THHN insulation
- Install a continuous equipment ground wire
- Utilize GFCI outlets in kitchen, bathrooms, laundry, etc
- Consider tamper resistant outlets if you have kids
- Look into AFCI breakers for fire prevention
Follow all current electrical codes for your region. Getting the proper permits and inspections is critical for safety and insurance purposes.
Consider hiring an electrician if you lack experience with home wiring projects. They can ensure your new electrical system is robust, efficient and meets all regulations.
Conclusion
While no longer used today, understanding obsolete wiring methods can help you gain insight into upgrading an older home. Knob and tube, armored cable, and cloth-insulated wiring may be relics of the past, but their remnants still lurk in many old houses.
With proper safety precautions and modern materials, you can leverage these historical wiring techniques to make rewiring your vintage home easier. Just make sure to discard any hazardous old materials and adhere to modern codes.
Hopefully this guide gave you some inspiration and context for tackling your own rewiring project! With the right planning and skills, you can give an old house new life with a refreshed electrical system.