Replacing Knob-and-Tube Wiring in Hidden Wall Cavities

I recently decided to replace the old knob-and-tube wiring in my home's hidden wall cavities. This antiquated wiring system can be dangerous and needs to be upgraded to modern standards. Here's what I learned through the process:

Evaluating the Scope of the Project

The first step was to evaluate how much of the wiring needed replacement. I had a home inspector identify all areas where knob-and-tube wiring was still present. He looked in the attic, basement, and used inspection cameras to peer inside the walls.

• In total, knob-and-tube spanned three floors and was used for nearly half of my home's circuits.
• Replacing all of this would be a major undertaking, but essential for safety.

I also had an electrician do a thorough assessment. Key aspects he checked:

• Condition of the wiring: Brittle, cracked, or otherwise damaged insulation can be a fire hazard.
• Branch circuit capacity: Knob-and-tube is often undersized for modern electrical loads.
• Grounding: Old systems typically have no ground wires.

Hiring the Right Electrician

This would be a large project, so I wanted to find the right electrical contractor. I got estimates from three local electricians.

Key factors in my decision:

• Experience with knob-and-tube replacement - this is complex work.
• Understanding of old wiring systems - to trace circuits and reuse wiring where possible.
• Skill working in tight spaces - fishing new wires through walls.
• Attention to minimizing damage - patching holes, matching textures.

I selected a contractor who had tackled many whole-house knob-and-tube replacements. The estimate was reasonable and included patching walls/ceilings.

Running New Wires Through Hidden Wall Cavities

The most challenging part of the project was extending new wiring through inaccessible wall cavities. The electrician used a few techniques:

• Fishing wires by accessing walls through light fixtures, vents, etc. This requires patience!
• Removing baseboards or ceiling trim to create access points along the cavity.
• Cutting access holes in walls and ceilings where needed. Holes are patched once wiring is complete.

I'm glad I hired a pro who knew tricks for fishing wires through challenging areas. He was able to avoid major demolition.

Key Elements of the New Electrical System

The electrician upgraded my wiring in several important ways:

• Grounded circuits: Installed grounded Romex wiring to replace old knob-and-tube.
• AFCI protection: New breakers help detect dangerous arcs and prevent fires.
• More circuits: Added circuits to reduce voltage drop and meet current electrical code.
• Higher capacity: Upsized wiring where needed to handle modern loads.

Overall, the new system is much safer and designed for modern energy demands.

Repairing Walls, Floors, and Ceilings

Once the knob-and-tube was removed and new wires installed, it was time to repair the structural damage. The contractor:

• Patched holes with matching drywall, plaster, or wood pieces.
• Refinished areas with texture and paint to blend the patches.
• Re-installed baseboards and trim work.

I'm satisfied with how clean the repairs turned out. You'd never know walls were cut into from how seamless the patches blend.

Lessons Learned

This major electrical upgrade was definitely worthwhile for safety, but taught me some lessons for future home projects:

• Get multiple quotes - I saved money with the third bid.
• Inspect beforehand - Know the full scope before starting.
• Hire experienced pros - It's worth it for complex jobs.
• Communicate clearly - Discuss access points and damage repair expectations.

For any homeowner considering knob-and-tube replacement, be prepared for a process. But you'll gain invaluable peace of mind knowing your electrical system is safe and modernized.