Arc Fault Circuit Interrupter (AFCI) breakers have been on the rise ever since they were first introduced in the NEC’s electrical code in 1999.
Some will find it interesting that AFCI protection once was only required in bedrooms. However, AFCI protection is now required by the NEC in almost every single room in our homes, including our bedrooms.
But why was AFCI protection required in bedrooms to begin with? The National Electrical Code (NEC) first required AFCI protected outlets in bedrooms in 1999. Industry professionals think that AFCI protection was implemented to prevent house fires caused by electrical arcs in lamps, alarm clocks, and other electrical devices plugged into outlets near flammable materials such as curtains and bedding, which could cause a fire while sleeping.
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Since the NEC implemented AFCI requirements in 1999, their use has been expanded throughout most of the electrical circuits in houses. Let’s examine arc fault circuits further to explain the NEC’s logic in implementing these safety measures.
AFCI circuits are an interesting piece of technology
They have and continue to prevent a large number of house fires from ever happening – essentially saving a lot of lives in the process.
Understanding their function a bit better will help us make sure we have provided the necessary safety for our family and us.
What Is an AFCI Outlet?
An Arc Fault Circuit Interrupter (AFCI) is a device that can be found in electrical outlets and electrical breakers. It protects against electrical fires that can start from electrical faults such as arcing.
The AFCI continually monitors the electrical circuits it is installed on, and if it detects any signs of an electrical arc, it will cut out the power to that circuit. It is thus preventing the arc from happening.
AFCI outlets are an alternative to the AFCI circuit breakers in modern electrical panels. These outlets have “Test” and “Reset buttons, making it easier to test whether they are functioning as intended. AFCIs can be seen as circuit breakers that have a more specific task. See our article on testing AFCI circuits at How to Test AFCI/GFCI Circuits.
AFCIs were first introduced back in the late 90s and, ever since then, have been considered a must-have according to the electrical code.”
And there is a good reason for that as more than 30,000 electrical fires are caused by arc faults each year. (1)
1. What Is an Arc Fault?
An arc fault can happen, for example, if we have two exposed wires close to each other.
In this scenario, the electricity can jump between the two wires using the air as a conductor. This jumping of electricity between two conductors (the two wires) is known as an arc fault.
There are two types of arc faults:
- Parallel arc fault – This is an arc that happens between different wires.
- Series arc fault – This is an arc that is happening along the same wire.
2. Why Is an Arc Fault Dangerous?
An arc fault is dangerous for several reasons:
- GFCI outlets and electrical circuit breakers may not register it and respectively not trip.
- An arc fault produces high amounts of temperature and can lead to electrical fires. (The temperatures an arc fault can reach can be up to 35,000 degrees Fahrenheit.)
3. What Causes an Arc Fault?
Different things can cause arc faults. However, generally speaking, they happen because of conductors that have been compromised in some way:
- Loose wire connection points.
- Damaged appliance cords.
- Damaged electrical wiring.
- Worn out or frayed cable insulation.
- Bad installation of electrical cables.
Why Are AFCI Outlets Required in Bedrooms?
Appropriate arc fault protection needs to be installed in all dwelling rooms.
When the NEC first introduced AFCIs, they were required in all 15 and 20 amp bedroom receptacles.
Since then, the areas and rooms required have constantly been expanding with every code revision. Nowadays, AFCI protection is required in almost every room.
1. But Why It All Started with the Bedrooms in Particular?
We spend a lot of time in the bedroom, much of which is done while sleeping. We all know that people spend one-third of their lives sleeping, so it can be argued that we probably spend one-third of our day in the bedroom.
A high amount of electrical fires start from bad or malfunctioning receptacles or old electrical appliances. Since most people will spend a lot of time in their bedrooms, they will tend to use a lot of different gadgets, appliances, and equipment in their bedrooms.
Thus, it probably is no surprise that a lot of electrical fires start from the bedrooms.
Let’s take a look at the data gathered by the National Fire Protection Association (NFPA) (2):
- 17% of house fires involving electrical distribution or lighting equipment start from the bedrooms. This includes electrical fires that started because of lamps, light bulbs, cords, plugs, and more.
- 12% of the house fires due to electrical failure or malfunction start from bedrooms.
- The highest risk for an electrical fire to start is during the winter months.
Looking at the bigger picture, it is no surprise that one of the rooms that experts focused on first were our bedrooms.
2. Some Additional Details
First, let’s consider the time of the year during the winter.
Many people use different space heaters to keep the bedrooms warm and cozy. All of these, if not handled properly, can pose a latent fire risk.
Second, generally, we might have a lot of different electrical appliances in our bedrooms. We may frequently move them around or have their extension cords plugged into an outlet behind a bed, desk, or wardrobe. This may wear down the cord as they rub against the wire or subject it to bending. All this may cause the cable to get frayed with time.
Third, another reason for arc faults can be, for example, a nail that goes through the wire in the walls.
3. Older AFCI Outlets
It is interesting to note that older AFCI outlets could not provide the best protection against arc faults.
Because they were relatively new technology back, then they were not able to detect series arc faults. They were also known to ghost trip frequently. Which means they tripped without an apparent reason for that.
Later on, that was improved as the newer combination AFCIs were introduced, which offered protection against both electrical arcing types. It is important to keep in mind that a combination AFCI does not refer to GFCI protection but only to arcing types.
Where Do AFCI Outlets Need to Be Placed?
According to the National Electrical Code (NEC), all dwelling room outlets installed on 15 to 20 amperage electrical circuits must be with arc fault protection.
- Living rooms.
- Dining rooms.
- Laundry areas
- Sunrooms, and more.
The only areas where an AFCI outlet is not required are:
- Outside areas*.
*However these areas still need to be protected against ground faults.
What Causes an AFCI to Constantly Trip?
If your AFCI outlet (or breaker) trips frequently, this may signify a potential problem and needs to be inspected as soon as possible. Such signs should never be overlooked or ignored, as this may expose you or your home to risk.
An AFCI outlet may frequently trip due to:
- An arc fault.
- A short circuit.
- An electrical overload.
- Due to damage to the AFCI.
- Bad installation of the AFCI.
Do AFCI and GFCI Offer the Same Kind of Protection?
An AFCI outlet does not offer protection against the same things as a GFCI outlet does.
While an AFCI offers protection against arc faults (or electrical fires), the GFCI protects against ground faults (or electrical shocks).
The NEC has specific requirements for what type of electrical protection needs to be installed in different rooms and areas.
Some rooms and areas may require a GFCI protection but no AFCI and vice versa.
And in some instances, both an AFCI and a GFCI protection can be required for the same receptacle.
This can be done in a couple of different ways:
- Having a GFCI breaker installed with an AFCI outlet.
- An AFCI breaker with GFCI outlets down the circuit.
- Installing a dual-type of receptacles that have both GFCI and AFCI installed. Sometimes referred to as dual-function circuit interrupters (DFCI).
If you’d like to know more about how arc fault circuits work, check out our article How Arc Fault Breakers (AFCI) Work?