Rewiring your home can seem like a daunting task, but with the right preparation and safety precautions, it's possible to do it yourself without professional assistance. Here's a comprehensive guide on how to safely rewire your home on your own.
Understanding Home Wiring Basics
Before attempting to rewire anything, it's crucial to understand some basic home electrical principles. Here are the key concepts you need to know:
Electrical Current and Circuits
- Electricity flows in circuits. A circuit is a closed loop that allows current to flow from the power source to the electrical device and back.
- Current is the rate of flow of electrons in the circuit. It is measured in amps.
- Most household circuits are 120 volts. Higher voltage circuits are used for large appliances like stoves, ovens, etc.
Wiring Types
- Romex - The most common type of wiring used in homes today. It's flexible plastic-sheathed wiring that contains 3 insulated copper wires: hot, neutral, and ground.
- BX (Armored Cable) - Has an outer flexible metal covering for extra protection. Used for exposed wiring.
- Conduit - Metal or plastic tubing that protects wires routed through walls and ceilings.
Key Electrical Components
- The circuit breaker panel is the central distribution point for electricity in the home. It contains multiple circuit breakers that serve different areas.
- Receptacles (outlets) deliver electricity to devices plugged into them through hot and neutral wires.
- Switches control lights and fans by interrupting hot wires.
- The ground wire provides a safe path for electricity in case of faults, short circuits or surges.
Gathering the Right Tools and Materials
Rewiring requires working with dangerous high voltage electricity. Make sure you have these essential safety gear and tools:
- Wire stripper - For stripping insulation off wires
- Voltmeter - To test for live wires
- Clamps and staples - For securing wires
- Fish tape - For routing wires through walls
- Electrical tape - For insulating wire connections
- Cable ripper - For pulling out old wires
- Ladder - For accessing ceilings
- Safety glasses, gloves and boots - For protection
For the new wiring itself, make sure you have enough:
- Romex cable of the right gauge (10, 12 or 14 AWG depending on usage)
- Electrical boxes
- Receptacles and switches
- Circuit breakers if adding new circuits
- Conduit and fittings if using conduit
Shutting Off Power and Testing for Live Wires
Before doing anything else:
- Shut off the main breaker in the panel to cut power to the whole house.
- Turn off individual breakers for the circuits you'll be working on.
- Use a contactless voltage tester to confirm wires are dead. Test wires before touching them to avoid getting shocked.
- If you have to work close to live wires, turn off power at individual outlets by:
- Unplugging devices
- Removing outlet/switch cover
- Pulling out hot wire from the receptacle
- Place a piece of electrical tape over the breaker handles to indicate they should not be turned on.
Removing Old Wiring
To remove existing wiring:
- Review building plans to understand how wiring runs through walls and ceilings.
- Remove existing receptacles, switches and light fixtures from the walls.
- Carefully pull out old wires from boxes and conduits. Don't just cut them.
- Use a cable ripper if wires are stuck.
- Coil up and store any wires still in good condition for reuse.
- Inspect conduits to see if they can be reused. Clean out conduits with a pipe brush if needed.
Running New Circuits
Map out new circuit runs before installing anything:
- Decide locations for switches, lights, receptacles, etc.
- Plan circuit paths from the panel through walls, ceilings and conduits.
- For new receptacle circuits, do not exceed 10 outlets per 20A circuit to avoid overloading.
- When running multiple circuits, keep wire runs at least 6 inches apart for safety.
- Use cable staples every 4.5 feet and at least 1 foot from boxes when securing cables to framing.
Some tips for pulling wires:
- Use fish tape to route cables through walls and conduits. Have a partner feed the cable while you pull the fish tape.
- Lubricate cables and conduits with wire pulling lubricant for smooth pulling.
- Carefully bend cables around corners. Keep minimum 6 inch bend radius for Romex.
- Pull all wires of a circuit together. Don't pull one at a time.
Installing Receptacles, Switches and Lights
Follow these steps to properly install electrical boxes and devices:
- Choose right size electrical box for number of wires and devices. Use handyman boxes for retrofitting.
- Mount boxes flush with finished wall surface and nail to framing members.
- Install cables into the box with a minimum 6 inches of slack and secure with clamps.
- Use correct wire connectors - twist-on for Romex cable, set-screw for armored cable.
- Match wire colors - white (neutral), black (hot), green (ground).
- Ground the box itself by attaching a pigtail ground wire.
- Carefully fold in and push wires firmly into the box before installing the receptacle.
- Attach receptacles and switches securely with mounting screws.
For lights:
- Install approved lighting boxes secured directly to ceiling joists if using heavy fixtures.
- Connect the fixture ground wire to the grounding screw or wire in the box.
Connecting New Wiring to the Panel
Follow these best practices when connecting new branch circuits to the main panel:
- Shut off the main breaker! Verify there is no power before touching any panel wires.
- Identify the neutral and ground bus bars in the panel. Never mix them up or combine them.
- Route circuit wires neatly through knockouts and secure with cable clamps.
- Label both ends of wires clearly indicating their destinations.
- Use bolt-on or set-screw breakers. Push all the way in before tightening terminal screws.
- Verify black (hot) wires land on breaker terminals and white (neutral) wires land on neutral bus bar.
- Connect ground wires to the ground bus bar.
Testing New Circuits
Thoroughly test all new circuits before turning power back on:
- Do a final check for stray exposed wires or loose connections.
- Verify neutral and ground wires are properly landed in the panel.
- Inspect each box to ensure wires are properly secured and connected.
- Replace all covers on boxes before testing.
- At the panel, turn the new breaker on and individual breakers for each outlet.
- At each receptacle, plug in a tester to confirm hot, neutral and ground connections.
- Check each switch controls the correct lights.
- Fix any issues. Repeat tests until circuits are 100% working.
- Only after thorough testing should full power be restored to the panel.
By following these comprehensive steps, you can safely upgrade the wiring in your home. Always put safety first - if at any point you don't feel completely confident, it's best to call a licensed electrician. But with proper precautions, the right tools, and testing, this is a DIY project a homeowner can certainly take on.