Upgrading Knob-and-Tube Wiring in Older Homes

What is Knob-and-Tube Wiring?

Knob-and-tube wiring was commonly installed in homes built before the 1940s. It features insulated wires running through open air, Supported by ceramic knobs and tubes.

This old form of electrical wiring has some notable drawbacks:

• Fire hazard - The insulation on old wiring can become brittle and crack over time, exposing bare wires that can spark and cause fires.

• Insufficient for modern loads - Knob-and-tube wiring was not designed to handle the amount of electricity used by modern appliances and devices. This can lead to overloaded circuits.

• Difficult to modify - It is challenging to tap into knob-and-tube circuits to add new wiring. Retrofitting additional circuits requires running all new wiring.

• Inefficient - These older systems lose more energy than modern wiring due to lack of insulation around wires.

Why Upgrade from Knob-and-Tube Wiring?

There are several compelling reasons to upgrade old knob-and-tube wiring:

• Safety - Replacing knob-and-tube wiring eliminates fire hazards from degraded insulation and overloads. Modern wiring is intrinsically far less prone to sparking and ignition.

• Reliability - New wiring will provide steady, dependable power for today's electricity needs. You'll avoid flickering lights and overloaded circuits.

• Efficiency - Upgrading to modern wire with intact insulation boosts energy efficiency and can reduce electric bills.

• Expandability - It's easy to tap into modern wiring to add new circuits. You'll have flexibility for remodeling projects and adding outlets.

• Insurance - Many insurance providers won't cover homes with knob-and-tube wiring. Upgrading may be required to get coverage.

• Resale value - Knob-and-tube wiring can decrease property value and turn away potential buyers. Updated wiring makes your home more attractive.

Options for Replacing Knob-and-Tube Wiring

You have two main options when upgrading old wiring:

Complete Rewiring

This involves removing all the old knob-and-tube wiring and installing entirely new wiring throughout the home.

Pros:

• Provides optimal safety and reliability
• Allows reconfiguring wiring layout for greater efficiency
• May be required by insurance providers

Cons:

• Most expensive option
• Very disruptive - walls and ceilings need to be opened up

Pigtailing

With this approach, the existing wiring is left in place. New wiring is run alongside it, connecting to the old wiring via junction boxes.

Pros:

• Less expensive than full rewire
• Less intrusive installation

Cons:

• Old wiring remains in place as fire hazard
• Existing wiring limits reconfiguration options
• May not satisfy insurance requirements

I recommend getting quotes from licensed electricians for both options. While pigtailing is cheaper upfront, a full rewire may pay off long-term in safety, efficiency, and resale value.

Cost to Upgrade Knob-and-Tube Wiring

The cost to replace knob-and-tube wiring ranges from $3,000 to $15,000 depending on:

• Home size - More wiring required for larger homes
• Accessibility - Easier to run new wires through unfinished basements and attics
• Full rewire vs pigtailing - Pigtailing typically costs 50-75% less than a full rewire
• Electrician rates - Get estimates from multiple licensed pros
• Specialty circuits - Upgrades like 220V for laundry add cost
• Permit fees - Varies by municipality, averages $200

Many homeowners spread out the wiring upgrade over time to save on costs. Prioritize high-load circuits like kitchens first.

Electrical Code for Knob-and-Tube Wiring

The National Electrical Code (NEC) contains regulations related to knob-and-tube wiring:

• Not permitted in new construction - Has been banned from new builds since the 1962 NEC

• Must be in good condition - Wiring must lack cracks, breaks, or deterioration

• Junction boxes required - When pigtailing, junction boxes must isolate old and new wiring

• Overcurrent protection - Fuses or breakers must match wire size

Work with certified electricians to ensure any knob-and-tube upgrades meet all applicable codes. Permitted work can add value by making the home safer and more sellable.

Is DIY Wiring Replacement Possible?

I do not recommend DIY electrical work when upgrading knob-and-tube wiring. The risks of improper installation are too great, including:

• Fire hazards from imperfect connections
• Damage to your home's structure and finishes
• Failing to meet code requirements
• Voiding your insurance coverage

Electrical work also requires permits and inspections. Licensed electricians have the experience, tools, and know-how to safely replace old wiring. The peace of mind is well worth the investment. Attempting DIY wiring upgrades can endanger your most valuable asset - your home.

Finding Professional Help

Start by getting quotes from multiple licensed electricians when replacing knob-and-tube wiring. Look for these key qualifications:

• Licensed and insured - Verify they meet state requirements

• Experience with old homes - Ask about previous knob-and-tube projects

• Commitment to safety - They should prioritize permits, inspections, and code compliance

• Attention to detail - Neat, careful wiring work minimizes safety risks

• Responsiveness - Quickly return calls and provide clear estimates

Check reviews and ask for referrals from past customers. A little research helps find the best electrician for your wiring replacement needs.

Upgrading outdated knob-and-tube wiring improves safety, reliability, and efficiency. By following the guidance in this article, you can successfully modernize the wiring in your older home.