By Matt Menke

Matt Menke lives in College Park and is a licensed Maryland home inspector.

 This month, we’re talking about the electrical wiring that powers everything in your house. In the last few decades, new technology such as three-prong plugs, grounded outlets and ground fault interrupters (GFIs) have reduced the chances of getting a shock or having a fire. But unless your home has been professionally remodeled or rewired in the past few years, it may have many outdated features that you should understand for your protection.

Two-prong outlets in a three-prong world. Older two-prong outlets are not as safe as three-prong outlets and get even worse when people try to get around them by cutting off the third prong off an appliance cord to make it fit an old outlet. An adapter with a little wire that screws into the faceplate might work to ground the cord, but only if there is an uninterrupted connection all the way back to the breaker box. Wiring in many mid-century homes had no dedicated ground wire. It is required now, and old, ungrounded wires should be upgraded whenever you remodel. Most rooms these days are on multiple breakers with more outlets, making it less tempting to overload single outlets and less likely to leave you in the dark. 

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A ground fault interrupter outlet with test buttons and green indicator light
Courtesy of Nancy Welch

 Old/full circuit breaker boxes. Years ago, most people had fewer appliances. Modern refrigerators, air conditioners and washing machines are much more efficient, but your home’s main electrical panel might not be big enough to handle all the circuits you need. In the 1960s it was common for fuse boxes (and later circuit breaker panels) to be wired for 100 amps or fewer, which could only handle about six to eight circuits. These days, a large, luxury home might require 400 amps. 

 In this area, it would be common for a 2,000-square-foot home with central air or electric heat to have a 200 amp breaker box with space for 24 or more 15 and 20-amp breakers because the circuits are not all used at the same time. But some items like a garbage disposal should have their own circuit, and an electric hot water heater might take up two spaces for a 30-amp breaker. Resist the temptation to use half-size breakers to squeeze in a few more circuits or to run extension cords. With stoves, hot water heaters and furnaces moving away from gas to electricity, you will probably need more room in the near future. Time for a new, larger electrical box or at least a sub-panel.

Beware of hanging new ceiling fans from old fixtures. Ceiling fans are great for circulating air and cutting utility bills, and it seems easy to install one using the power from an overhead light fixture. Bad Idea. That old light might only weigh a pound or so, and one nut might be enough to support it. But fans can easily weigh 25 pounds, and they spin and vibrate, so they need to be mounted on the wood joists in the ceiling, not on a tiny electrical box that might be ok for a light. There are mounting kits available that attach between joists and can be installed through the little hole in the ceiling.

 Faulty ground fault interrupters. GFI outlets can save your life. They usually have a tiny green light and a reset button, and will instantly cut the power if you accidentally drop a toaster into the sink or a hair dryer into a tub. They began to be required for outdoor receptacles in 1971 and should be installed anywhere something electrical might get wet.

Many of our homes were built before GFIs became common, but they’re legally required upgrades when renovating bathrooms, kitchens and other areas. The problem is that some electricians have become very creative in finding ways to keep costs down by not replacing all the outlets required but adding a single GFI outlet between the electrical panel and the other regular outlets in the circuit. This might not protect you or it could cause frequent tripping. It can also make it very frustrating to track down exactly where the reset button actually is when the GFI trips and all the other outlets in the circuit stop working. 

Switches that play tricks. The lights over most hallways and staircases usually use what are called three-way switches. They have an extra wire running between them so as you walk through the house, you can turn the light on from one place and switch it off from another. Unfortunately, there are many ways that homeowners or inexperienced electricians can wire these switches that might work but are not up to code. Switches can also wear out to the point they get floppy rather than make a good connection and then stay in the proper position up or down. When a switch flops it can allow sparks to jump between the wire connections. If you ever see dark char marks on the cover plate, a visible spark or hear a loud pop, replace that switch.

Upgrading old switches and circuits is always the safe choice, but the high cost makes it tempting to take shortcuts. The best advice is to find a licensed electrician with a solid local track record who is familiar with vintage homes. Dodgy wiring is never the charming part of our quirky old houses.