How To Rewire Your Home’s Electrical System For Safety And Efficiency (With Pictures!)

Introduction

Rewiring your home's electrical system can greatly improve its safety, efficiency, and functionality. While it's a major project that requires permits and inspections, with proper planning and precautions it can be a very doable DIY task. I'll walk through the complete process of rewiring a home step-by-step, from deciding when it's time to rewire to installing new circuits, outlets, switches, and service panel.

When Is It Time To Rewire?

There are several signs that indicate your home's electrical system needs rewiring:

Old and Outdated Wiring

Homes built before 1960 likely have outdated 60-amp electrical service with ungrounded two-prong outlets. Rewiring upgrades the service to 100 amps or more and adds grounded three-prong outlets. Newer wiring is safer and meets modern electrical needs.

Frequent Tripped Breakers and Blown Fuses

If breakers trip or fuses blow regularly, it likely means the circuits are overloaded from additional appliances and devices. Rewiring allows creating dedicated circuits to evenly distribute the electrical load.

Flickering Lights and Dimming Lights

Flickering or dimming lights when appliances turn on indicate the electrical service can't handle the load. This brownout effect stresses the system and wiring. Upgrading the service capacity solves this.

No Grounding or Faulty Grounding

Ungrounded two-prong outlets don't safely divert electricity in a short circuit. Proper grounding is essential for safety. Rewiring upgrades ungrounded wiring and outlets.

Aluminum Wiring

Aluminum wiring was used in the 60s and 70s before being discontinued due to fire and safety concerns. Replacing old aluminum wiring with new copper wire removes the risk.

Gather Supplies and Tools

Rewiring requires a full assortment of electrical supplies and tools:

• Wire - I recommend THHN/THWN-2 copper wire; both solid and stranded wire are fine. Match wire gauge to circuit amperage.

• Conduit - Use EMT metal conduit for exposed areas; flexible PVC conduit works for buried feeders.

• Breakers - Choose breakers matching the amperage of the circuits. AFCI and GFCI breakers provide extra protection.

• Outlet and switch boxes - Use steel boxes for durability; plastic works too. Make sure they are rated for the number of wires inside.

• Outlets and switches - Buy extra capacity 20A receptacles and quiet switches. Include GFCI outlets near wet areas.

• Service panel - A main breaker panel with enough spaces for all circuits is ideal. Select appropriate amperage.

• Label maker - This helps label all wires and breakers cleanly.

• Electrical meter - An AC/DC clamp meter checks voltages and diagnostics.

• Safety gear - Wear insulated gloves, glasses, sturdy shoes, hard hat, and FR clothes.

• Hand tools - Lineman's pliers, cable cutters, strippers,screwdrivers, saws, hammers, tape, and more.

• Power tools - A rotary hammer drill expedites conduit and box installation.

Take Proper Safety Precautions

Electrical work poses serious hazards including electrocution, shocks, burns, and explosions. Follow these precautions:

• Turn off power at the main breaker before starting. Verify it's off with a voltage tester.

• Disconnect the grounding wire last when removing wires. Reconnect it first when wiring up boxes and appliances.

• Wear insulating gloves and shoes. Make sure there are no exposed conductors.

• Use GFCI protection whenever possible. GFCI outlets and breakers cut power if a current leak is detected.

• Work on only one circuit at a time. Label wires clearly and keep different circuits isolated.

• Use circuit testers to verify wires are dead. Check wires with a contact voltage tester before touching them.

• Keep the workspace clear of debris. Prevent slips, strips, or pokes that could make you contact live wires.

• Take regular breaks. Electrical work fatigues the body and mind quickly.

Obtain Permits and Schedule Inspections

Check with your local building department about permit requirements for rewiring a home. Provide your scope of work and they'll confirm what permits are needed.

Electrical and building permits are commonly required, involving plan reviews, inspections at several stages, and final approval. Having permits ensures your rewiring meets all codes - very important for safety and your home's market value.

Design and Plan New Wiring

Good design is crucial for an effective, efficient system:

• Evaluate electrical needs - Consider family size, appliances, electronics, and future expansion. This determines the service panel size and number of circuits needed.

• Choose wire size and type - Larger wire is better as it allows more power flow. Using only copper wire avoids aluminum wire issues.

• Plan circuit layout - Determine what rooms and uses each circuit will serve. Avoid overloading any one circuit.

• Include extra capacity - More outlets per room and thicker wire gauge prevents future issues. Build for next 50 years.

• Sketch a wiring diagram - Map out the service panel, wire runs, breaker assignments, and outlet placements for reference.

• List all materials needed - Accurately calculating materials for the job helps minimize costs. Order 10-20% extra.

Remove Old Wiring

The first step of the actual rewiring is removing the old wiring:

• Turn off main breaker and verify it's dead. Check with a contact voltage tester.

• Remove cover plates from outlets and switches. Take note of wiring connections.

• Disconnect all wires from outlets and switches. Carefully label wires as you remove them.

• Detach wires from service panel. Be methodical in labeling breakers.

• Pull wires out of boxes and conduit. For buried cable, clip it flush with wall studs.

• Remove abandoned junction and outlet boxes. Patch over holes or install blank cover plates.

• Vacuum boxes and conduits clean. Remove all old insulation, clips, staples and debris.

Install New Service Panel

Upgrading the main service panel is often part of a rewiring project. Key steps include:

• Choose a service panel location - Garages, utility rooms, and basements are convenient spots.

• Mount the new panel securely - Follow manufacturer clearance requirements. Keep 6.5 ft minimum head space.

• Run conduit and wires to panel - Use appropriate gauge wires for the amperage. Include separate neutral and ground.

• Install a main breaker - Match the amperage of the main breaker to the service panel rating.

• Ground the panel properly - Bond the panel to ground rods driven into soil or connect to water pipes.

• Connect all grounds - Splice ground wires to the ground bus bar in the panel. Keep them isolated from neutrals.

• Double check connections - Verify proper wire stripping, tight terminal screws, and tight cable clamps.

Run New Circuit Wiring

Running new wiring is the most labor intensive phase:

• Plan each circuit's route - Visualize the most efficient path using minimal conduit and boxes.

• Mount outlet and switch boxes - Position at standard heights based on use. Spacing varies by locale.

• Install conduit between boxes - Run through stud bays or use surface mounted conduit. Avoid tight bends.

• Pull wires through conduit - Use wire lube if pulling through multiple bends. Don't exceed bend radius.

• Pull extra wire length - Provide 8-12 inches of slack in the box for connections.

• Label wires clearly - Use wire number or color tapes to identify hot, neutral, ground.

• Connect wires securely - Wrap solid wires clockwise, stranded wires counterclockwise around screws.

Install Devices and Covers

The final major task is installing all the outlets, switches, cover plates, and lighting:

• Strip wires properly - Match strip length to outlet terminal openings. Avoid nicking copper.

• Connect outlets and switches - Follow manufacturer wiring diagrams. Use stranded wire for plug-in appliances.

• Install cover plates - Check for correct fit over outlets and switches.

• Mount lights and fans - Use fixture boxes rated for weight of ceiling fans.

• Group rooms on circuits - Avoid crossing hot wires between rooms.

• Balance circuit loads - Mix lighting, outlets, and appliances across circuits.

• Link smoke detectors - Connect so if one alarms, they all do.

Inspect and Test the Electrical System

Thoroughly test all wiring before closing up walls:

• Turn power back on - Restore power at the main breaker once everything is complete.

• Check all outlets and lights - Verify proper operation of every outlet, switch and bulb.

• Test each circuit's load - Plug high wattage heaters into outlets to confirm no tripping or heat rise.

• Fix any loose connections - Check wires for warm spots and tighten terminals as needed.

• Confirm proper grounding - Test each outlet's ground using a circuit tester.

• Check for continuity - Verify all connected devices share common hot, neutral, and ground.

Schedule Final Inspections

The final step is coordinating official inspections:

• Call for rough-in inspection - This checks that wiring is properly secured, labeled, and functional before it gets covered by insulation and drywall.

• Request final inspection - After all switches, outlets, and fixtures are installed, the final inspection verifies proper operation and safety.

• Complete any final checklist items - Make any corrections the inspector identifies before approval.

• Obtain certificate of occupancy - Once the electrical rewiring is fully approved, the city will issue an occupancy certificate.

Rewiring a home is a major undertaking but pays big dividends in electrical safety, performance, and peace of mind knowing your home's power system is modernized for decades to come.