Introduction
Rewiring a home from the 1920s can be a daunting task, but with proper planning and safety precautions, I was able to rewire my entire house without any major issues. In this comprehensive guide, I'll walk you through all the steps I took to upgrade my wiring to modern standards, from assessing the existing system to installing new circuits. I learned a lot through trial and error, so hopefully my experience will help simplify the process for you.
Dangers of Old Wiring
Before diving into a rewiring project, it's important to understand why it's necessary in the first place.
Outdated Materials
Homes built in the 1920s likely have knob and tube wiring, which has insulation that easily cracks and fray over time. This can lead to exposed wires that present a fire hazard. Additionally, the wiring may contain cloth insulation that disintegrates when exposed to heat.
Insufficient Circuitry
Older homes often have fewer circuits than are necessary for modern households with numerous appliances and electronics. Overloaded circuits can overheat, also creating fire risks.
Lack of Grounding
Proper grounding provides a safe path for electricity to follow in the event of a fault. Older wiring often lacks grounding, meaning there's greater risk of shocks or electrocution.
While rewiring may seem intimidating, the dangers of outdated wiring make the project absolutely necessary for safety.
Developing a Rewiring Plan
Careful planning is crucial when taking on a major rewiring endeavor. Here are some key steps:
Consult an Electrician
While a skilled DIYer can rewire a home, it's wise to consult a licensed electrician first. They can assess your existing system and provide rewiring recommendations tailored to your house.
Choose a New Panel
Upgrading your electrical panel provides more capacity for new circuits. Talk to your electrician about the ideal panel setup. 200 amps is common for modern homes.
Map Out New Circuits
Decide where you want new lighting, outlets, appliance circuits, etc. Create a circuit plan noting the wire size, breaker amperage, and outlets for each new circuit.
Purchase Materials
You'll need various gauges of copper wiring, junction boxes, receptacles, breakers, conduit, and tools. Buying everything ahead of time makes the job smoother.
Create a Timeline
Rewiring a whole house could take several weeks to months. Make a realistic timeline outlining which circuits you'll tackle first.
Safety Tips for Rewiring
Electrical work presents serious hazards if proper precautions aren't taken. Here are some key safety measures:
- Turn off power at the main panel before working. Verify it's off by testing outlets with a multimeter or voltage tester.
- When turning the power back on to test, only energize the individual circuit you're working on.
- Wear insulating rubber gloves and boots when handling wires. Never work on live wires.
- Use fiberglass ladders and insulated tools. Never use aluminum ladders which conduct electricity.
- Install GFCI outlets as an extra protection against shocks.
- Keep flammable materials away from work areas in case sparks occur.
- Work with a partner who can shut off power or call 911 in an emergency.
- Cover or take down any hanging wires you're not actively working on.
Removing Knob and Tube Wiring
Let's get into the actual rewiring process, starting with removing the old wiring. Here are the steps:
Locate all Access Points
- Remove cover plates to find where wiring enters electrical boxes.
- Inspect the attic, basement, and crawlspaces for additional access points.
- Look for knob and tube wires along joists, studs, and rafters.
Take Detailed Photos
- Thoroughly photo document the wiring routes before disturbing anything. This provides a reference later.
- Label the photos to identify locations.
Disconnect Old Wiring
- Starting at the panel, disconnect the old circuits you'll be removing.
- At each box and access point, disconnect and remove the old wires.
Remove Knob and Tube Fixtures
- Take down any porcelain knobs, tubes, and junctions.
- Remove or scrap any old light fixtures on outdated wiring.
Cap Off Wires
- Place wire nuts on the disconnected wire ends so they don't fray.
- Wrap electrical tape around the nuts for extra protection.
Fishing New Wires
With the old wiring out of the way, it's time to run new wire through the house:
Plan Circuits and Wire Routes
- Have your circuit plan available to follow. Verify you have enough wire on hand for each run.
- Map out the exact route through walls, joists, and studs for each circuit.
Select Appropriate Wire Size
- For 15 amp circuits, use 14/2 gauge wire with ground. For 20 amp circuits, use 12/2 wire with ground.
- Using overly thin wire can lead to overheating, so stick to standard sizes.
Cut Access Holes
- Use a drywall saw to cut rectangular openings where you need to route wire between rooms.
- Drill holes in studs and joists following your wire routing plan.
Fish Wires Through Walls
- Use fish tape to thread new wires through walls and ceilings between access holes.
- Have a partner feed the fish tape and wire from the other access point.
Label Wires
- As you pull new wires into boxes, label each end identifying the corresponding circuit. This avoids confusion later.
Installing New Electrical Boxes
Properly installing electrical boxes takes precision - here are some tips:
Choose Appropriate Boxes
- Use metal new work boxes when installing receptacles and switches in new drywall.
- For existing walls, old work boxes fit between studs or joists.
Position According to Code
- Outlets must be 12-18 inches above floor level based on location.
- Light switch boxes go 48-60 inches above floors. Consult electrical code.
Securely Fasten Boxes
- Anchor new work boxes by tightening clamps against studs or joists.
- Old work boxes should be screwed into place for stability.
Connect Grounding Wires
- Attach a ground wire to each box using the green screw inside.
- Connect all ground wires at outlets using wire nuts.
Connecting Switches and Receptacles
The fun part is installing shiny new switches, outlets, and light fixtures:
Install Neutral and Hot Wires
- Connect the white neutral wires in the back of each box using wire nuts.
- Connect hot wires to switch or outlet brass screws.
Attach Devices to Boxes
- For outlets, feed wires through the holes and tighten side screws to secure.
- Light switches screw directly to the switch box.
Use Device Plates
- Screw on wall plates to cover electrical boxes and prevent shocks.
- Use extra-duty plates where outlets are lower than normal.
Test Each Device
- Turn the circuit on and plug in a lamp or tester at outlets.
- Flip switches to verify lights turn off and on properly.
Troubleshoot Any Issues
- If outlets or lights are unresponsive, check all connections and verify wires are intact.
Wrapping Up the Project
You're almost done! Here are the final steps:
Insulate Wires
- Place fire resistant insulation like fiberglass batts or foam around new wires.
- This prevents inadvertent wire damage and meets fire codes.
Patch Holes
- Repair any drywall holes from fishing wire using joint compound and drywall tape.
- Sand smooth and repaint patched areas.
Label New Panel Circuits
- Creating a circuit list noting which breaker controls each outlet or light.
- Place the list on the inside of the electrical panel door for easy reference.
Hire an Inspector
- Schedule an inspection by your city or county to verify all work meets electrical code.
- Make any corrections noted and get final approval.
Congratulations, your home's electrical system is now as modern and safe as it gets! Be sure to take precautions like turning off power and wearing PPE whenever modifying wiring in the future. You should now have confidence to take on additional upgrades like installing a new ceiling fan or adding outdoor lighting. Just follow proper safety procedures and your 1920s era house will keep shining bright for decades to come!