I have an older home built in the 1920s that still has the original knob and tube wiring. This obsolete wiring system can be a fire hazard and limits my ability to use modern appliances and devices. I want to rewire my home but am unsure of the process. Here is what I learned about safely rewiring a home with old knob and tube wiring.
Understanding Knob and Tube Wiring
Knob and tube wiring was commonly installed in homes built before 1950. It features:
- Ceramic knobs - Used to hold wires apart and prevent contact
- Tubes - Hollow conduits wires pass through for protection
- No ground wire - Only hot and neutral wires
- Wooden sills - Wires often run over sills in walls
Some key problems with knob and tube wiring include:
- Fire hazard - Insulation degrades over time
- Insufficient for modern loads - Not designed for today's electricity demands
- Exposed wires - Knobs and tubes deteriorate leaving bare wires
- Difficult alterations - Hard to splice new wires into old system
Upgrading is recommended. Rewiring increases safety and allows modern electrical use.
Hiring an Electrician
Hiring a professional electrician is highly recommended over DIY. Rewiring a home is complex and potentially dangerous.
Key reasons to hire a pro:
- Experience - They've done this many times before
- Efficiency - It will go much faster with their skills
- Safety - Risk of shock or fire if wiring incorrectly
- Inspection - Often required after upgrades like this
I obtained quotes from 3 licensed electricians before selecting one. They assessed my home's wiring and explained the plan.
Preparing for a Rewire Project
Before wiring, I needed to:
- Clear access - Remove clutter and obstructions along walls
- Create openings - Electricians may cut holes to route wires
- Disconnect knob and tube - Shut off power and remove fuses
- Arrange time off - I needed to be home during work hours for access
- Keep pets and children away from work area
- Avoid using water near exposed wires
- Check credentials of professionals
- Turn power off fully before they arrive
I set aside a full week for the project. Actual rewiring took 3 days with prep work on either end.
New Wiring Installation Process
The electrician team took the following steps to rewire my home:
1. Shut Off Power
They arrived wearing protective gear and verified power was off with a voltage tester. All original fuses were removed to ensure knob and tube wires were not live.
2. Run New Wires
Modern NM cables were routed from the electrical panel through walls and ceilings to each fixture. Existing knob and tube was left in place for removal later.
3. Install Devices
- Outlets - Grounded and tamper-resistant
- Switches - New decorator style switches
- Fixtures - Updated light fixtures with ENERGY STAR models
4. Connect Circuit Breaker Panel
The main panel was upgraded to fit modern breakers. Each circuit was carefully labeled.
5. Remove Old Wiring
Once fully operational, they returned on day 3 to remove the obsolete knob and tube wires. This prevented any risk of accidental shock.
The completed rewire work passed inspection on the first try. The inspector checked all visible wiring as well as outlets and fixtures.
The entire house now has modern wiring ready for today's electricity needs and safety standards. I can use high-power appliances without fear of hazardous overloaded knob and tube circuits. The potential fire risk has been eliminated as well.
Cost to Rewire a House with Knob and Tube
My 1,200 square foot home cost $8,400 in total for parts and labor. This broke down to:
- Labor - $6,000
- Supplies - $2,000
- Permit fee - $400
On average, rewiring a house runs $8-15 per square foot depending on:
- Home size
- Construction difficulty
- Local electrician rates
- Required updates to breaker panel
While expensive, this essential upgrade greatly improved safety. It also increased my home's value and functionality.
- Knob and tube wiring is obsolete and can be a fire hazard
- Hiring a professional electrician is highly recommended
- Extensive access and preparation is required before starting
- Rerouting new wires can take 2-3 days
- Cost ranges from $8-15 per square foot on average
- Results are safer, more functional modern wiring
I am relieved to have full peace of mind knowing my home's electrical system is now completely up-to-date and meets the latest safety codes. The investment was worthwhile. Let me know if you have any other questions!