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When Do I Need to Replace Old Electrical Wiring?

Sep 8, 2023 | Electrician Program, News

Faulty wiring was the second leading cause of residential fires between 2012 and 2016, according to a 2019 report by the National Fire Protection Association (NFPA). Knowing when wiring needs to be replaced will help you prevent fires in your home, and it can also help lower your electricity bill. Here are some things to understand when you are considering whether the wiring in your home needs to be updated or replaced.

How to Identify Old Electrical Wiring

If you don’t know when your home’s wiring was installed, there are things you can look for that indicate the age of the wiring.

Here are some signs of old electrical wiring:

  • Outdated electrical panels: Electrical panels are the fuse box of your home, and they distribute electricity received from your service provider. If your fuse box is tripping or failing often, your fuse box is likely old and unable to handle modern power requirements.
  • Aluminum wires: Between 1960 and 1970, aluminum was less expensive than copper, so aluminum was more commonly used for electrical wiring. But aluminum is not as safe as copper, and it has a higher chance of sparking due to overheating. Aluminum wiring can cause dangerous and deadly fires and should be replaced.
  • Cloth insulation: In the 1950s, people used cloth to insulate electrical wiring. If you find looms or pieces of fabric anywhere in your wiring, you should replace your electrical wiring and insulation immediately.
  • Knob and tube wiring: This is an old form of wiring, joined through studs, walls, and floor joists, and it doesn’t meet the modern requirement of three-phase power.

Safety Issues with Old Electrical Wiring

Old electrical wiring can pose an electrocution or fire risk for several reasons. If you did not live in your home when the wiring was installed, you can’t be sure the electrical system is up to code. And materials like wire insulation deteriorate over time.

If you don’t know when your wiring was last inspected, it is definitely worth having a qualified electrician take a look at it, especially if you notice any warning signs of faulty wiring.


Signs of Faulty Wiring

  • Frequent circuit breaker trips: Tripped breakers are not uncommon, but frequent circuit breaker trips should raise a red flag. Either there is an issue with your home’s electrical wiring, or your electrical panel needs to be upgraded.
  • Frayed wiring: Frayed wiring is always a problem. If a wall is exposed in your home and you notice frayed wiring, you should contact an electrician right away because it is a fire and shock hazard.
  • Dimming lights: During a thunderstorm or windy weather, your lights may flicker, possibly because of a tree branch that has fallen on a nearby power line. But if your lights flicker on a clear day, your home’s electrical wiring may need to be upgraded.
  • Smoke and outlet discoloration: If you see smoke, you need to take action right away, because the presence of smoke means there’s a fire. Scorch marks on an outlet also warrant action. There could be loose wiring inside the outlet, causing an arc, which is when electricity jumps from one connection to another. You should contact an electrician and unplug all of your appliances until the electrician arrives.
  • Warm, vibrating outlets: A properly functioning outlet should be cool to the touch. If you notice warmth or vibration coming from an outlet, there is likely damaged wiring inside it. A cord plugged into the outlet can catch fire, so you should address this issue right away.
  • Strange noises from outlets and fixtures: In addition to heat, arcing causes a buzzing sound. If you hear a buzzing or sizzling sound coming from an outlet or light fixture, you cannot rule out bad wiring.

Electrify Your Career: Find Your Path with EIT’s Programs

With a commitment to excellence in education and a curriculum tailored to industry demands, EIT’s programs offer the knowledge and skills you need to electrify your career and make a meaningful impact in the world of electrical engineering.

Do I Need To Replace the Wiring in My Old House?

If you have identified old wiring in your home or noticed any of the signs of faulty wiring, it is in the best interests of your safety and finances to replace the wiring in an old home.

If your home is 30 or more years old, you should consider replacing its electrical wiring. Homes built before 1985 can have old and outdated wiring. Wiring in older homes is often for only 60 amps, and newer appliances require upwards of 200 amps. Not having enough voltage can damage your appliances, computers, and other electronics.

Wiring usually lasts between 50 and 70 years, but many factors can affect the longevity of wiring, including:

  • The installation process
  • Exposure to heat
  • Attacks by rodents and termites
  • Exposure to UV light
  • Excessive flexing
  • Exposure to chemicals

As previously mentioned, frequent breaker trips, dimming or flickering lights, and discolored outlets are all signs that your wiring needs to be replaced.

Here are some other reasons you may need to update your wiring:

  • You’re relying on extension cords—this means you don’t have enough outlets
  • You have two-pronged, ungrounded outlets, which pose a shock risk
  • You don’t have ground fault circuit interrupter outlets (GCFIs) in your kitchen or bathroom—GCFIs are designed to automatically cut off power if there is a spike in current to help prevent fires and electrocution
  • You don’t have arc-fault circuit interrupters (AFCIs) in bedrooms, sleeping areas, kitchens, and laundry areas
  • You get a light shock or tingle when using appliances
  • You have a lingering burning smell
  • Your insurance refuses coverage or charges a higher premium for older wiring


Everything Seems to Work—Why Would I Update My Home’s Electrical Wiring?

Even if you’re not noticing any signs of faulty wiring, there are still reasons why you should update wiring in an old home. If your home is more than 40 years old, you may have knob and tube wiring. This type of wiring has one black charged wire and one white neutral wire. Electrical tape may have been used on ungrounded, soldered wires to form splices and wire connections. And some insulation used before 1960 was made of rubber that was known to crumble and flake. Issues with insulation can be dangerous and not up to National Electrical Code (NEC) standards.

NEC standards are consistently upgraded to provide the latest regulations on electrical wiring, overcurrent protection, grounding, and installation of equipment. Following code doesn’t always require replacement of wiring. If your local code allows it, you can splice old knob and tube wiring with a new, non-metallic cable if you use a junction box, which protects wire connections.

Aluminum wiring is more likely to cause fires, so you should replace aluminum wiring with copper wiring. Even if your house was built as late as the 1970s, you have a safety hazard if your wiring is aluminum.

Understanding the Benefits of Installing Copper Wiring In Your Home

Although aluminum wiring was installed between 1965 and 1973 because it was cheaper than copper, copper wiring is far superior in terms of safety. Here are some of the reasons why copper is the ideal electrical wiring material:
Ductile and malleable: Because copper is ductile, it can be easily hammered into a thin wire for electrical needs. Its malleability allows it to be bent into shape.
Excellent conductor: Copper conducts electricity better than any other non-precious metal. Conductivity is an essential component of electrical wiring.
Non-corrosive: Copper wiring is non-corrosive, meaning it won’t rust or degrade. It can last 40 years or more.

Does Homeowners Insurance Cover Rewiring?

First, it’s important to look carefully at your homeowners insurance policy. Many insurance companies do not provide coverage if your home has wiring that is more than 40 years old or if you have knob and tube or aluminum wiring.

Your homeowners insurance policy may cover damaged wiring, including your electrical panel, but it may not cover certain wiring issues, such as faulty workmanship or repair.

Steps to Update Wiring in an Old House

1. Plan and prepare

A detailed plan of your project will help you keep your drywall on. You should consult a professional electrician to help you design this plan. You’ll need to prepare a detailed plan of the old circuitry, a detailed plan of the new circuitry, and wiring calculations to determine the amount of wires and cables needed and the most efficient routes for the new circuit.

2. Prep work stage

New wires will have to be run through the crawl space or in some cases the attic, which means you need to make room for them to slide through. Doing this will also mark down a clear path for what needs to be removed and for feeding the new wiring to the outlets. You should clear the area around electrical outlets in your home and make sure the electricians will have easy access to install the wiring.

3. Removal stage

Wires are often stapled to the framing, so they can’t just be pulled out of the wall. After your power is off, the electrician may cut the cable and remove the part that’s exposed, leaving the buried cable in the wall. Some cables are in more convenient locations and can be pulled out more easily. In this case, the electrician can tape the new cable to the old one and then pull the old wiring out and allow the new cable to take its place.

As a note, old wiring cannot be discarded in the trash—it needs to be recycled.

4. New wiring stage

Before running a new wire, the electrician will have to pre-cut an opening for each box of the circuit’s electrical devices. Next, a ¾ inch hole will be drilled in the top plate of the wall, directly on top of each opening, or in the bottom plate, under the openings. This is usually a two-man job, as it helps to have another person catch the wire that is being fed through the crawl space.

The wire should feed down straight into the opening in the wall, and the process continues room by room until all wiring is sent down to the correct outlet.


How to Become a Skilled Electrician

If you’re interested in understanding how electrical wiring works, when and why you need to replace it, and how to rewire your home on your own, Erie Institute of Technology offers a 15-month training program that will prepare you for a successful career as an electrician.

During our Electrician Program, you’ll become familiar with national electric code requirements and the tools of the trade while learning how to install and maintain power systems in homes, businesses, and factories.

Invest in your education and your future. Apply online today or visit our website to learn more about our programs.

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