How to Safely Replace Knob and Tube Wiring in Your Historic Home

Introduction

Replacing knob and tube wiring in a historic home can seem daunting, but with proper planning and care it can be done safely. As the owner of a historic home, preserving its unique character while upgrading critical safety systems like electrical wiring is so important. In this article, I'll walk through the key steps I took to successfully replace the knob and tube wiring in my 1920s craftsman bungalow while protecting its historic integrity.

Why Replace Knob and Tube Wiring

Knob and tube wiring was common in homes built before the 1930s. It features individual wires run through knobs fastened to framing and porcelain tubes to keep wires separate. While this old wiring worked fine for smaller electrical loads of the past, it can be dangerous in a modern home:

• Fire hazard - the old, brittle wiring is prone to cracking and sparking. Knob and tube lacks ground wires which are essential for safety.

• Insufficient for modern loads - today's high-wattage electronics, large appliances, and increased lighting needs can overload the small gauge, limited wiring capacity.

• Insurance and resale difficulties - most homeowners insurance policies won't cover homes with knob and tube. Many buyers shy away from homes needing extensive rewiring.

Though inconvenient, upgrading the wiring protects my family and enables us to enjoy modern amenities. The project does require balancing safety with preserving the home's historic finishes.

Finding the Right Electrician

The key is finding an electrician experienced in both historic homes and current code compliance. I asked neighbors for referrals and also consulted our local historic preservation society for recommendations. I made sure to find someone who:

• Has extensive experience rewiring historic homes. Look for 10+ years working on similar vintage homes.

• Will take steps to minimally impact historic finishes like lath and plaster walls. You want someone accustomed to fishing wires through finished walls.

• Is licensed, insured, and pulls all required permits. You want someone who does things by the book.

I ultimately chose a local electrician who specializes in historic homes, which gave me confidence they could do the job while being sensitive to preserving the home's historic aspects.

Creating a Rewiring Plan

Before work began, my electrician and I walked through the home together to map out a rewiring plan. Key factors we considered:

• Scope - Which circuits need upgrading? Prioritize high load areas like the kitchen first.

• Access - How will new wiring be fished through finished walls? Identify routes and access points.

• Original floors/walls - Avoid damaging intact vintage finishes. Using attic access and basement ceiling access points can prevent tearing up original plaster walls.

• Fixtures - Reuse, rewire or replace period light fixtures so as not to change the historic aesthetic.

Careful planning is crucial for smoothly rewiring while protecting your home's historic finishes. Discuss any concerns with your electrician so they can accommodate accordingly.

Protecting Historic Finishes

Rewiring requires cutting into walls and drilling access holes. Special care must be taken around fragile lath and plaster walls, vintage wood floors and decorative trims. My electrician followed these best practices:

• Limit wall damage - Use existing penetrations like vents or ducts to insert wires whenever possible. Fish wires carefully through walls minimizing holes.

• Patch with in-kind materials - Repair lath and plaster properly with similar vintage materials. Match wood floors or trims with equivalent species and trim profiles.

• Restore finishes - Refinish damaged areas to blend with surrounding texture and color. A good plasterer can match existing adjacent plaster.

• Consult on fixture reuse - Properly rewire and reuse period light fixtures to preserve the home's historic look.

Take your time selecting an experienced electrician willing to take extra care. It makes all the difference in maintaining your home's historic charm through an electrical upgrade.

Adding New Circuits and Grounding

Beyond just swapping old wires, a rewiring allows you to add new circuits and additional outlets to support modern electrical needs. It also provides the opportunity to fully ground the electrical system and add arc-fault protection to greatly improve safety. Key upgrades I implemented:

• More 20A small appliance circuits - Added dedicated circuits with ample outlets in the kitchen and bathrooms to handle more devices.

• GFCI protection - Added ground fault circuit interrupters in bathrooms, kitchen, laundry and other wet areas.

• AFCI protection - Installed arc-fault circuit interrupters on bedroom circuits to prevent fires.

• Proper system grounding - Grounded all outlets and circuits back to the main electrical panel for safety.

The full rewire brought our 1920s wiring up to modern safety standards. I now have a safer, more functional electrical system that will meet our needs for decades while preserving the historic ambience we love.

Final Thoughts

Replacing the knob and tube wiring took more time and careful planning compared to a standard house rewire. But protecting the historic finishes while gaining safety and functionality was well worth the investment. By selecting an experienced electrician and involving them in strategic planning from the outset, the project succeeded in upgrading this critical system without sacrificing our home's vintage historic charm and character. If you take similar care to be selective and plan thoroughly, you can confidently modernize while preserving the best of your own historic home.