How to Replace Old, Outdated Wiring in Your Home

Introduction

Replacing old, outdated wiring in your home is an important project that can significantly increase your home's safety and value. With wiring that is many decades old, you may be at risk of electrical fires or other dangers from deteriorated insulation, improper grounding, or insufficient capacity to handle your home's electrical needs. Thankfully, with careful planning and some basic electrical skills, I can tackle this project myself in a weekend. In this article, I will walk through all the key steps involved in replacing old wiring, from deciding which circuits need an upgrade and mapping out a plan, to installing new wires, outlets, switches, and service panels. Let's get started!

Assessing Which Circuits Need Upgrading

The first step is to inventory all the wiring in my home to decide which circuits need upgrading. I'll make a list of all the rooms and label which circuits power each one. For any circuit that is:

Two-pronged (no ground) - These older circuits need upgraded to current three-pronged grounded wiring.
Cloth-insulated - Outdated cloth wiring without proper insulation is a major fire hazard.
Small gauge - Thin 12 or 14 gauge wiring that lacks capacity for higher power needs.
Aluminum - Aluminum wiring requires special connections to avoid corrosion and overheating issues.

I'll mark down any circuits showing these red flags. I'll also consult an electrician if I have any concerns about the overall condition, capacity, or safety of my electrical service panel and main feeds. They can provide professional advice on any service upgrades needed.

Mapping Out a Wiring Plan

Next, I'll map out a plan for running new wiring to replace the outdated circuits. I'll sketch out each room and trace where the old wiring runs through walls, floors, and ceilings.

For each circuit:

I'll note the wire gauge so I can match it for the new wiring.
I'll label all the outlets, switches, lights, and appliances powered by the circuit.
I'll chart the most efficient path to run the new wires to each device. Sometimes it's better to take a different route than the old wiring.
I'll verify I have enough capacity on my main electrical service for any circuit upgrades to a higher amperage.

Careful planning at this stage will make the rewiring go smoothly and minimize opened walls. I may also consider relocating outlets and switches to more convenient locations during the process.

Gathering the Right Materials

Before getting started, I'll make sure I have all the necessary materials on hand:

NM-B electrical wire with ground - getting the appropriate size for each circuit.
Breakers - standard and GFCI types for circuits requiring them.
Junction boxes - for splicing wires and making connections.
Conduit - flexible plastic conduit for covering new wire runs.
Outlets and switches - match the number of old outlets and style.
Wire strippers, needle nose pliers, screwdrivers, and other hand tools.
Drywall repair materials - joint compound, tape, mud pan, sandpaper.
Wall fish tape - for running wires inside finished walls.

Getting all the supplies organized ahead of time will prevent delays once the rewiring work begins.

Shutting Off Power and Removing Old Wiring

Before removing any old wiring, I'll go to the main service panel and shut off the breaker for the circuit I'm working on. I'll double check that power is off using a non-contact voltage tester. Safety first!

I'll remove any wall outlet and switch cover plates and unscrew the devices to disconnect the old wires. For runs that are easily accessible, I can pull the old wiring out. For finished walls, I may need to carefully cut out sections of drywall to access the wiring.

If the old wiring has insulation in good condition and is not cloth-insulated, I may be able to use it to help pull the new wire into place. I'll cut back the old wires and secure the new ones to the ends with electrical tape for this "pulling" process.

Running New Wires

Now the fun part begins - running the new replacement wiring!

I'll start by routing the new wires through holes I've cut to access each point along the circuit. For finished walls, I'll use a fish tape to snake wires through voids in the framing.

At each junction box, I'll use wire nuts to connect the incoming and outgoing new wires properly. I'll match all wire colors consistently and ensure firm twist-on connections.

For new outlet and switch boxes, I'll carefully strip the ends of the new wires and connect them to the device contacts - hot (black), neutral (white), and ground (green or bare).

If the circuit requires a GFCI outlet, I'll take care to connect it at the start of the run to protect the whole string of outlets. The same goes if AFCI breakers are needed.

Installing New Outlets, Switches and Breakers

After all the new wires are run, connected, and secured, it's time to finish things up:

I'll securely mount the electrical boxes and reinstall the outlets and light switches in place.
I'll label each new circuit at the service panel and install the appropriate amperage circuit breaker.
For any sections of drywall I had to remove, I'll patch these areas and blend with paint when dry.
I'll use electrical tape to cap off any ends of old wiring until it is fully removed.
Lastly, I'll turn the power back on and do some tests - flipping switches, plugging in devices, checking for proper grounding.

Once everything checks out, my home's electrical system is safer and up to current code! Replacing the outdated wiring went smoothly thanks to proper planning and safe installation practices.

Hiring an Electrician

While a diligent DIYer can replace old wiring, it's smart to know when to call in a professional electrician:

If dealing with aluminum wiring, as it requires special handling.
For a new circuit panel or electrical service upgrade.
If you need to run new wiring routes involving heavy demolition.
Where electrical work would require a city permit and inspection.
If the scope of work is beyond your skill level and experience.

Professional electricians have the expertise to fully assess your electrical systems and execute complex upgrades properly. They can ensure all work adheres to local codes.

Replacing outdated wiring takes time and diligence, but brings your home's electrical system up to modern safety standards. With good planning and safe installation practices, you can tackle this essential upgrade project and get peace of mind. If the scope grows beyond DIY work, don't hesitate to call in an electrician.