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

Why Replace Knob and Tube Wiring?

Knob and tube wiring was commonly installed in homes built before the 1940s. While it was suitable for the electrical needs of the time, knob and tube wiring can be dangerous by today's standards for several reasons:

• Fire hazard - The old, brittle insulation can crack and expose bare wires, increasing fire risk. Knob and tube wires are often spliced together in concealed spaces, creating potential fire hazards.

• Insufficient for modern loads - Knob and tube wiring was not designed to handle the amount of electricity that modern appliances require. Overloaded circuits can overheat, arc, and cause fires.

• No grounding - Knob and tube systems have no equipment grounding, increasing the risk of shock and damage to connected devices during surges or faults.

• Insurance issues - Many insurance companies will not insure a home with knob and tube wiring or charge a higher premium. Fixing wiring issues may be required for coverage.

• Resale value - Knob and tube wiring can make homes difficult to finance or sell. Many buyers will not consider purchasing a home without modern, grounded wiring.

For safety and to protect your investment, replacing knob and tube wiring is highly recommended.

Dangers of DIY Knob and Tube Wiring Replacement

While replacing knob and tube wiring yourself may seem like a way to save money, it is extremely dangerous for those not trained as electricians to attempt. Hazards include:

• Electrocution - Old, brittle insulation increases the risk of exposed live wires. Working on live circuits can result in serious injury or death by electrocution.

• Fire - Improper connections, overloaded circuits, or damaged wires can arc, spark, and cause electrical fires in walls and ceilings.

• Shock and electrocution risks - Lack of training in safety procedures like de-energizing circuits, testing for live wires, and proper grounding increases risk.

• Damage to home - Mistakes during installation can require extensive repairs to walls, ceilings, and other surfaces damaged during electrical work.

• Insurance issues - Any home electrical work done improperly may nullify your homeowners insurance if hazards result. Liability for injuries also becomes your responsibility.

Unless you are a licensed electrician, replacing knob and tube wiring yourself is extremely dangerous for you and your home. The risks far outweigh any potential savings.

How Professional Electricians Replace Knob and Tube Wiring Safely

Hiring licensed, insured electricians to replace knob and tube wiring is strongly advised. Here is how they will safely upgrade wiring in your home:

Evaluation and Planning

• Thorough inspection to locate all knob and tube wiring runs, splices, and junction points.
• Evaluate condition of existing insulation, circuits, and electrical loads.
• Create a detailed plan for new wiring routes and required materials.
• Obtain proper permits and approvals before starting work.

Prep Work

• Turn off power at main breaker panel and verify circuits are de-energized.
• Remove any accessible knob and tube wiring like in attics and crawlspaces.
• Identify potential hazards like asbestos which may require abatement.

Installing New Wiring

• Fish walls with protective conduit to pull new wiring between access points.
• Maintain fire separations and avoid spreading fire hazards in walls.
• Connect new grounded wires to circuits at junction boxes and outlets.
• Install GFCI outlets anywhere wiring passes near water sources.
• Repair all holes or damage from electrical work.

Completion

• Reconnect power and meticulously test each circuit for faults.
• Verify proper grounding and bonding of outlets and electrical panels.
• Provide documentation of completed work and dispose of old wiring properly.

Replacing knob and tube wiring is extremely dangerous for untrained homeowners. Hiring professional electricians following safety procedures is strongly advised. The cost is well worth eliminating the very real hazards posed by defective vintage electrical systems.

Questions to Ask Electricians About Knob and Tube Wiring Replacement

When obtaining quotes for rewiring your home, asking the right questions ensures you choose qualified, experienced professionals.

• Are you licensed, bonded, and insured?
• How long have you been replacing knob and tube wiring?
• Will you provide a detailed quote for the project scope?
• Do you obtain proper permits for electrical work with the city?
• What safety procedures do you follow?
• How do you ensure new wiring is properly grounded?
• How and where will you run new wiring through the home?
• How long will the project take until completion?
• What work is done to repair walls, ceilings, etc. after install?
• Do you guarantee your work if issues arise later?

Thoroughly vet any electricians before hiring them to replace knob and tube wiring. Check reviews and references to verify they consistently do professional, safe electrical work at fair prices. Never attempt DIY electrical work in your home unless you are a licensed electrician.

Cost to Replace Knob and Tube Wiring

Exact costs to rewire a home depend on factors like:

• Home size and wiring complexity
• Accessibility to wiring runs (attics vs buried in walls)
• Amount of drywall work and repairs needed
• Local electrician labor rates

According to HomeAdvisor, typical costs fall in these ranges:

• Small home (under 1500 sq ft): $4,000 to $8,000
• Medium home (1500 - 2500 sq ft): $8,000 to $12,000
• Large home (over 2500 sq ft): $12,000 to $15,000

Upgrading from knob and tube wiring can be a significant investment. However, it may be required by your insurance provider and is strongly recommended for safety. Many homeowners consider the cost well worth it for peace of mind.

Alternatives to Full Rewiring

If the full cost of rewiring your entire home is prohibitive, alternatives like a partial upgrade may suffice:

• Prioritize problem areas - Focus first on circuits with heaviest loads like kitchens or laundry. Also replace wiring near plumbing, in attics, or with damaged insulation.

• Isolate unused circuits - Replace wiring to outlets, lights, and appliances you actively use. Remove unused, hazardous knob and tube runs.

• Implement overcurrent protection - Fuses or circuit breakers that shut off power during overloads can improve safety if replaced selectively.

• Use GFCI outlets - Replacing ungrounded outlets with GFCI outlets can help mitigate shock risks inexpensively.

While a full rewiring is best, prioritizing the highest risk wiring for replacement can be a less costly compromise, if done by an electrician.

In Summary

Here are key points to remember about safely replacing knob and tube wiring:

• Knob and tube wiring poses significant fire, electrical shock, and insurance risks. Replacement is highly recommended.

• Never attempt DIY electrical work unless you are a licensed electrician. Dangers include electrocution, fires, shocks, and costly damages.

• Hire licensed, insured electricians to perform wiring replacements safely following proper procedures.

• Thoroughly vet electricians and get multiple quotes before selecting one for the job.

• Rewiring costs vary based on home size and complexity but typically range from $4,000 to $15,000.

• Partial upgrades are a less expensive alternative but a full rewiring is best for safety.

Replacing hazardous, outdated wiring requires electrical expertise. With proper professional help, you can make your home safer and more valuable for years to come.