Knob and tube wiring was commonly installed in homes built before 1950. The system of copper conductors, held down by porcelain knobs, started being used in the late 1800s. It is risky to have in modern homes. Aside from degradation from age and wear, knob and tube wiring lacks a ground wire, which increases the risk of shock and appliance damage. Heat can be trapped under high loads, so an electrical fire is a risk if wiring is located near insulation.

However, there are benefits to knob and tube wiring that were once practical in the average home. The reasons this arrangement was so common in the past include:

  • Wires Could Be Hidden Out of Sight: It was easy to install wires where they couldn’t be accessed or cause potential harm, including under floors, within the linings of walls, or in ceilings.
  • Affordable Installation: The materials were cheaper than others available at the time, while labor was more affordable too. Labor costs have increased dramatically over the years. One reason knob and tube wiring became less popular was because it is very labor intensive to install.
  • Heat Dissipation: At loads up to 10 amps, heat generated by current was quickly dissipated, which kept the wires cool. Compared to other types of wiring available at the time, it could support a higher amp capacity.
  • Longevity: Porcelain components are highly durable and have a long lifespan. It wasn’t likely that a homeowner would have to replace their wiring system anytime soon. Porcelain knobs, while resilient, are both insulating and prevent over-tensioning so wires last longer.
  • Supported the Basic Electrical Needs of Homes: During the times knob and tube wiring was used, homes didn’t have as many electrical appliances. But it was just fine for lighting. Such is not the case for 60-amp electrical systems, let alone homes using 150 to 200 amps, as any modifications to knob and tube systems to adapt to this could have been done improperly.

Are There Still Any Benefits to Knob and Tube Wiring?

This old arrangement poses a fire risk, so it’s a safety hazard that should be addressed. While no building code requires the complete removal of knob and tube wiring, insurance companies may deny coverage to homeowners because of the fire risk it presents. If you have knob and tube wiring, at the very least have it inspected right away to ensure it was installed properly and hasn’t been unsafely modified.

But leaving the system in place restricts what you can use it for. It will not support rooms with multiple appliances. Nor is it suited for kitchens, bathrooms, or laundry rooms. The lack of grounding makes it too dangerous. If you are considering a knob and tube upgrade, it is best to consult a professional electrician.

Contact Express Electrical Services

At Express Electrical Services, we specialize in knob and tube wiring upgrades and replace outdated systems with modern electrical wiring, high-capacity circuits, three prong outlets, and arc fault protection. Our technicians can install whole house surge protection as well. We provide same-day service and can enable you to safely run modern-day appliances such as central air conditioners, washers and dryers, jacuzzis, as well as computers and entertainment systems. To learn more about what we can do and schedule service to prevent power outages, shocks, fires, and electrical damage, call us at 323-727-7799 today.