Everything to know about GFCI
When people are buying a home one of the most common things an inspector will point out is "you are missing GFCI". This poses a lot of questions. I mean after all, you're a home buyer, not an electrician. Why do I care about GFCI? I commonly get the following questions, and I hope to answer all of them for you.
Is GFI the same as GFCI?
GFI stands for ground fault interrupter. GFCI stands for ground fault circuit interrupter. It is 2 ways of describing the same thing. Different codes and jurisdictions name it differently though.
What is GFCI?
A GFCI is a device integrated into outlets and breakers that monitors the current coming in and out of the circuit. All power must return to its source, so if more power is leaving the device than returning it means the power is finding another way back to its source. This is very likely through a person, so the GFCI will "trip" cutting the power to the outlet or breaker. potentially saving the user's life.
With that in mind, a GFCI is not an excuse to be reckless with electricity, because you can have a pretty serious shock before it trips. They are designed to trip within 1/10th of a second if a drop of more than 5 mA (Milli Amps) is detected. This sounds fast, and 5mA sounds like a small tolerance, but it can still be deadly. In addition, if it is seized or defective it may not trip at all. About 5% of the GFCIs that I test don't trip, and I would not bet my life on those odds, but if I would get shocked accidentally I sure want a GFCI there.
Do GFCIs need maintenance?
Now, what can cause a GFCI to cease or fail? Some of them come defective from the factory, but most electricians will test them after installation. Another large failure is improper installation, which is why it's so important to hire a qualified contractor. But the most common issue is that they seize up from lack of use. Thankfully the average person does not get shocked enough to exercise the mechanism, so the manufacturers had that in mind and designed a way that tests, and exercises the mechanism at the same time. When you push the "test" button on a GFCI, it sends some power to bypass the outlet, simulating a shock. This will cause it to trip (making a popping noise), in the same way as if someone is getting shocked. This test should be performed once a month to ensure you're being protected, and to exercise the mechanism. After you push the "reset" button it will continue to work as usual. If it does not trip you will need an electrician to replace it.
How do I identify a GFCI?
A GFCI can easily be identified by its "Test" and "Reset" buttons. But don't let the lack of them fool you. Sometimes a seemingly normal outlet can be protected by a GFCI "upstream". This means if any of the outlets sense a shock it will turn off the power for all of them. This can be tested by pushing the "test" button on all of the GFCI outlets and breakers in your house and seeing if it still has power. If it does not have power, it is under that GFCI and you can reset them and know you are protected.
[For more technically inclined people, you can try it in reverse. Buy an outlet tester (around $10 on Amazon), plug it into the outlet, and push the test button on the tester. If the outlet loses power it is protected, and all that's left is to find the GFCI that tripped. But the risk of doing this is the GFCI that tripped can be powering important electronics, such as computers, or refrigerators, and it can be on the other side of the house, or behind a built-in cabinet. it can be extremely difficult to locate or reach.]
Where do I need GFCI?
If this device is so amazing why don't we have them everywhere? Let's first talk about your skin for a minute. Your skin is your first layer of defense against electricity, and it does a decent job at protecting you when it's dry. (Not to say you can't get killed if you are dry, but it's less likely). When your skin gets wet it takes a lot less current to get through your skin. An example of this would be a 9-volt battery. If you touch both ends with your skin, it's not going to hurt you, but I'm sure you all remember your friends as kids betting you to lick it, and you get that tingle on your tongue. Now a 9-volt battery is only around 9 volts, a household outlet in the US is 120 volts, over 13 times more powerful than a 9-volt battery. So if it can get through your skin it can easily kill you. In addition, electricity can travel through water very easily, meaning if you drop a toaster into a sink full of water, all you have to do is stick your finger in to get shocked. Knowing how much more dangerous electricity is when you are wet, any outlet that can come in contact with water should be GFCI protected, including any outlet near a sink, bathroom, exterior, garage, pool equipment, jet tubs, laundry rooms, vehicle chargers, and any wet area.
How does electricity kill you?
there are 2 main ways electricity can kill you. Your body uses electrical pulses to communicate to your muscles, and a shock can cause you to lose the ability to control them. If someone grabs an electric wire it can cause your mussels to tense up and they will be unable to let go. The whole time it is shocking you, it is burning you, and if you are unable to let go it will eventually cook you alive. The 2nd way it can kill you is if the electricity goes through your heart. The electricity can confuse your heart and cause it to stop beating. (This is why if someone is having a cardiac arrest, and their heart is beating in an unregular way, shocking them through the heart can reset it and give it the opportunity to start beating again).
If I have an older house that is "grandfathered" in should I upgrade to GFCI?
Older houses may have been built before GFCI was required, and technically there is no code requiring you to install them. But the same can be said with cars. Most newer cars come standard with numerous airbags, seat belts, backup cameras, crumple zones, automatic emergency braking, and more. If you have a car built before 1968 it is not required to have seat belts, however, that does not mean you will be safe in an accident. The same thing is true with GFCI, your house may be legally "grandfathered" in, however, it does not mean you will be safe if you get shocked.
In summary, GFCIs are cheap, extremely effective devices that save lives every day. It's always a good idea to upgrade older houses with them, and test them on a regular basis.