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Tue, Oct. 22

Electrical 101: Breakers, eyeball polishers, and AFI vs. GFCI

I have had several questions recently regarding electrical wiring, panels, breakers, outlets, etc. Some of these I've written about before, but not for several years. I have greatly summarized the questions so I have adequate space for my typically long, wordy and sometimes irrelevant answers.

From a real estate agent: "Why do inspectors mention 'undersized breakers' but make no recommendation, but call 'oversized breakers' a major defect?"

Well, let's say there is 20 amp (12 gauge copper) wire to your bathrooms, which are on the same circuit. That circuit should have a 20 amp circuit breaker to protect it. Now let's say you have a house full of family and guests. It's a little early for Christmas, so maybe someone's getting married. There are two girls in each bathroom. Each girl is using some of those electric appliances I see in bathrooms, such as hair dryers, curler heaters, mascara installers, ear lobe cleaners, eyeball polishers, etc. With four of these appliances in use at the same time, there are more than 20 amps going through the wires. Without a circuit breaker, or if the circuit breaker is too large, the wires will melt and start a fire. So an "oversized" circuit breaker is a major defect because it's a fire hazard.

Now if the circuit breaker was only 15 amp, but the wire/circuit was 20 amp, there is no safety concern. The worst thing that can happen is the circuit breaker will trip off before the girls can turn on all four appliances.

Now before you start sending me emails accusing me of being sexist, let's be totally honest. I've literally inspected 10,000 bathrooms. Men may have up to two electrical appliances in a bathroom (but often none); they may use an electric razor or electric toothbrush. Women have a six-way adapter in their outlet and six appliances plugged in. Most men can only identify one or two of these appliances.

So, an oversized breaker may not trip off when needed, resulting in a fire hazard. An undersized breaker may trip off when the circuit is not actually overloaded, resulting in an inconvenience (to go find the panel and reset the breaker). And the same thing is true for the electrical service (coming into the home) and main breaker. If there is a 200 amp service and a 200 amp main breaker in a 100 amp panel, it is possible that more than 100 amps could go through the panel and something bad could happen. But if there is a 100 amp service and 100 amp breaker in a 200 amp panel, the worse that can happen is the main breaker will trip off.

The next question also came from a real estate agent, wanting to know why inspectors test and recommend GFCI protection in older homes but not AFI protection. A quick summary: GFCI stands for Ground Fault Circuit Interrupter. In most homes the GFCI protection is provided by GFCI outlets, which have a "test" and "reset" button. These are shock-preventing outlets, and are found in kitchens, bathrooms, garages, and the exterior (and a few other places). GFCI has been required in some locations since the 1970s.

AFI stands for Arc Fault Interrupter, which is a fire preventer. These have been required on bedroom circuits for about 12 years. Arc fault protection is provided by AFI circuit breakers in the panel. These breakers have a "test" button just like a GFCI breaker. There is usually one AFI breaker for each bedroom, although it's also common to have one AFI breaker for two secondary bedrooms.

So, why do home inspectors test and recommend upgrading to GFCI protection, but not AFI protection? The simplest answer is that Arizona specifically requires us to test GFCIs, but not AFIs. And there is a reason for this. GFCI protection is easy to test for. GFCI testers are only a few dollars and readily available. Testing the GFCI protection will shut off power to all kitchen, bath and garage outlets. So the seller may find a coffee maker clock flashing "12:00" when they get home. GFCI protection is easy to provide/install where needed. If you have an older home, you can install a GFCI breaker, or a single GFCI outlet, which will protect all the kitchen or garage outlets.

AFI protection is only required on bedroom circuits (so far, that's changing). And AFI protection can only be provided by an AFI breaker. So my policy, like many other inspectors, is to test AFI breakers in a vacant home. But I do not test them in an occupied home because it will shut off all power to all the bedrooms. I may be turning off alarm clocks or VCR timers (all right, DVR timers). I often have not been in the home when I inspect an electrical panel - I could be turning off an aquarium or the seller's oxygen, which would be a little more inconvenient than your DVR not recording your favorite show.

And it is much more difficult to add AFI protection to an older home. You can install GFCI outlets anywhere. In newer homes AFI protection is required for the entire bedroom, which includes all lights and outlets. So most newer homes have a circuit that is only for a bedroom. But in older homes, a circuit may be for some of the bedroom outlets and some of the living room outlets. Or the bedroom lights could be on one circuit, and the outlets on another. So you could end up installing several AFI breakers and still not have full AFI protection in every bedroom.

As usual, I ran out of room before I ran out of words. I'll have to finish the AFI discussion next time.

Randy West owns Professional Building Consultants in Prescott. He is state-certified and has performed more than 7,000 home inspections in the Prescott area. West serves on the Home Inspector Rules and Standards Committee for the Arizona Board of Technical Registration. Contact him at or visit

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