Introduction
Rewiring a home can seem like a daunting task, but with proper planning and precautions, it is possible for a dedicated DIYer to take on. Rewiring without professional help can lead to huge cost savings, as electrician fees often run in the thousands of dollars. However, safety should be the number one priority - working with electrical wiring presents real hazards if proper protocols are not followed.
This guide will walk through the complete process of rewiring a home, from assessing the existing electrical system, planning the rewire, purchasing materials, installing new wiring and components, and finally testing the new system. Critical safety advice is provided for each step. While expertise is required, this shows it is possible to gain the skills needed to rewire your home through research and careful practice. With patience and attention to detail, you can take control of this major home project and avoid paying electrician markup.
Assessing the Existing Electrical System
Before beginning a rewiring project, you must understand the current state of your home's electrical system. This involves both safety considerations and planning how the new wiring will integrate. Key steps include:
Document the Circuit Breaker Panel
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The circuit breaker panel is the central component that connects all home electrical circuits. Open the panel and photo or draw each circuit breaker and what it controls. This provides a reference for the existing wiring system.
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Note any signs of corrosion, heat damage, or broken breakers - these indicate issues to be resolved.
Check Condition of Existing Wiring
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Examine all accessible wiring, including receptacles, switches, and light fixtures. Look for insulation damage, corrosion, and improper connections. These must be addressed before reusing any wiring.
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Verify the wire gauges used - wire that is too small can overheat and cause fires. Recommended gauge depends on circuit amperage and length.
Identify Hidden Wiring Runs
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Use a cable tracer to locate any hidden wiring runs in walls, ceilings, and floors. Map where wiring is present to avoid hazards when making cuts during rewiring.
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Inspect wiring in the attic or basement if accessible. Look for breaches in insulation that may cause shorts.
Consider Adding Capacity
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Evaluate if the existing electrical service provides adequate power for your needs. Upgrading the main service panel may be required to support additional circuits.
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Decide if you want to add circuits to support more lights, switches, and receptacles. This will affect rewiring requirements.
Developing a Rewiring Plan
Careful planning is crucial when taking on a major electrical project. Consider the following when developing a rewiring plan:
Choose a New Service Panel
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Select a large enough main service panel to handle all existing and new circuits you need. Read amperage ratings closely.
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Breakers must match panel brand - choose a common brand like Square D or Eaton for compatibility.
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A 200 amp panel is typical for many homes. Larger homes may require 400 amps or more.
Decide on Wiring Approach
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Running all new wiring is the most thorough approach. However, you can also leave properly functioning wiring and run new wires only where needed. This saves work.
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Upgrading partially may introduce inconsistencies. Balance cost savings against having uniform wiring.
Develop a Circuit Map
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Diagram each new circuit required, including lights, outlets, appliances, and any special purpose circuits.
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Indicate wire gauge and breaker size for each new circuit based on expected electrical load.
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Plan circuit routes from the panel to endpoints for efficient runs.
Consider Installation Order
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Stage the work so you can maintain power to critical circuits like refrigerator and freezers.
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Rewire one circuit at a time to avoid confusion - label each wire as you go.
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Save access challenges like running wires through finished walls for last.
Purchasing Materials
With a rewiring plan completed, now purchase the necessary materials and tools:
Electrical Wire
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Copper wire only - never use aluminum wire for home rewiring.
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Purchase 2-conductor and 3-conductor wires to support typical 120V and 240V circuits respectively.
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The required wire gauge depends on circuit amperage and length. Follow codes for sizing.
Outlet Boxes and Conduit
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Choose metal outlet boxes - they are more durable than plastic.
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Flexible metal conduit allows wires to be snaked through tight spaces.
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Non-metallic conduit can also be used in dry locations. It is rigid.
Circuit Breakers
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Match breaker brand and amperage rating to the service panel.
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AFCI and GFCI breakers provide important shock and arc fault protection. Use where required by code.
Miscellaneous Materials
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Junction boxes, wire nuts, cable staples, faceplates, and other parts.
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Cable ripper, fish tape, multimeter, wire strippers and more tools.
Installing New Wiring and Components
With planning and purchasing accomplished, now the hands-on work begins. Take it one step at a time:
Mount the New Service Panel
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Shut off main breaker and remove old panel. Label existing wires as you disconnect them.
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Install new panel as per manufacturer instructions. Connect grounding and supply wires first for safety.
Run Box-to-Box Circuits
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Start each circuit by installing outlet and junction boxes needed for the run.
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Use conduit between boxes to protect wires. Fish wires through before mounting boxes.
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Always connect wires inside boxes using approved methods like wire nuts.
Connect Switches and Receptacles
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Attach switches in between outlet boxes. Run 3-wire cable to support each switched light.
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Cap all unused wires with wire nuts for safety. Include extra wires in each box for expansion.
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Use pigtails to connect outlets and switches so hot wires remain continuous.
Label all Circuits
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Create a legend showing which breaker controls each run. Include outlet and switch locations.
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Label wires using numbered tape any time multiple wires enter a single box.
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Place legend inside service panel for future reference.
Testing and Validation
With the new wires run and connected, it is time to validate proper function and safety:
Torque all Connections
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Use a torque screwdriver to tighten all new wire connections to spec. Prevent loose wires.
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Over-tightening can also damage wires. Follow torque ratings.
Verify Proper Grounding
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Confirm ground wires are continuous and properly connected for all circuits.
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Test GFCI outlets using the test and reset buttons to confirm grounding function.
Perform Insulation Testing
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Use a megohmmeter to verify insulation resistance on all circuits. Look for damage allowing shorts.
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Minimum resistance should be 1 megohm - investigate any lower readings.
Power-Up and Test
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Energize the main breaker and methodically turn on each circuit, checking for proper function of all lights, outlets, and switches.
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Use a multimeter to verify correct voltage on outlets. Record readings for each circuit.
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Operate all 240V circuits and listen for uneven hum indicating an open neutral.
Conclusion
Rewiring an entire home is a complex project that requires planning, electrical skills, and extreme care. While hiring a professional electrician may be the best option, some homeowners may choose to take on this challenge themselves and reap significant cost savings. This overview provides the key steps involved, with tips to maximize safety and success. Pay careful attention to local building codes and permit requirements as well. With diligence and common sense, rewiring a home without an electrician can be accomplished.