Home Wiring 101

Close-up of the ends of several exposed copper wires in colored insulation, including blue, yellow with green stripes, black, and brown, against a dark background. The wire strands are neatly bundled and visible.

On average, outdated and faulty wiring causes 25,900 electrical fires per year. These fires lead to 280 deaths, 1,125 injuries, and about $1.1 billion in property damage. It’s important to make sure that your wiring is up to date and operating safely to prevent this from occurring in your home.

If your house was built before 1950, or if your wiring hasn’t been upgraded since then, odds are you have a system of wiring called “knob and tube.“ Knob and tube wiring consists of ceramic knobs to hold the wires in place and ceramic tubes that insulate wires through walls studs and floor joists. You can tell this is the system installed in your home if you see a lot of two-pronged outlets around. This system only employs two wires instead of three, leaving your electricity ungrounded. The two wires are also insulated with rubber instead of plastic. Rubber degrades over time which leaves your wires exposed to air and moisture, increasing the opportunity for corrosion as well as shorts and fires.

Knob and tube wiring is worth replacing for financial reasons as well. Some insurance companies will refuse to insure your home if you have this wiring system. Others might charge a higher premium because of the relative dangers of the system.

If your house was built between 1962 and 1972, it’s very likely that you have aluminum instead of copper wiring installed due to how expensive copper was at the time. This is dangerous because aluminum is much more prone to corrosion. Corrosion is a fire hazard and only gets more dangerous as time passes. Your best bet is to replace all of the wiring in your home with copper wires. If this isn’t a possibility, installing copper connectors, or “pigtails,” at receptacles and circuit breakers can mitigate the risk of fire.

Other ways to tell if you need to upgrade your wiring are: frequently blown fuses or tripped circuit breakers; a tingling sensation when you touch appliances; flickering or dimming lights; too few switches, outlets, and lights; and/or frequent extension cord use. Any of these could signal a multitude of problems, all of which are dangerous and should be remedied as soon as possible.

Upgrading the wiring throughout your home isn’t a small undertaking, but it’s one worth doing. Rewiring a 1,500 to 3,000 square foot home can cost between $8,000 and $15,000. It can take anywhere between 5 and 14 days and is a very invasive undertaking since the electrician will have to open your walls to do it. It’s best to rewire during another remodeling project, as they generally already require opening up walls and can expedite the process. You can also opt to install structured wiring when you rewire, which includes heavy-duty data cables. This will prepare you for the demands of future appliances and even some already on the market such as TVs and smart thermostats. Also, installing wire that is one size larger than required will pay for itself and begin providing savings after about two years.
In order to ensure the safety of your family and property, make sure that the wiring in your home is up-to-date. Doing so will save you money down the road, and potentially your life.

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