One major concern while using a furnace, or any electrical equipment for that matter, is the appliance’s ability to prevent fires. And AFCI is the ideal tool to stop this from occurring. But is it necessary for your furnace?
Yes, it is the answer. For a number of domestic electrical circuits, including furnaces, the National Electrical Code (NEC) requires AFCIs.
Continue reading to learn what an AFCI is and how it operates. We’ll also go over how it differs from a GFCI and why having one is crucial.
AFCI: What Does It Mean?
Arc-Fault Circuit Interrupters is another name for them. Specialized electrical outlets, circuit breakers, and receptacles are used in residential branch wiring in order to identify and respond to potentially fatal electrical arcs.
The Function Of AFCI Circuit Breakers
When an AFCI detects electric arcs, a sign of poor connections in domestic wiring, it shuts off the circuit. Loose connections have a tendency to get hotter over time and occasionally develop the potential to cause a house fire.
When switches, plugs, and brushed motors operate normally, an arc that could be dangerous and one that is not is selectively distinguished by an AFCI.
What Causes Electrical Arc Faults?
An electrical current will ignite, or arc, between metal contact points when there is an intermittent contact caused by corroded or loose wiring connections.
Arcing produces high-intensity heating with a point temperature of 10,000 °F, easily igniting adjacent materials like insulation or wood framing.
Typically, an arc fault can happen in one of two ways:
1. Parallel Arc Fault
Parallel arcing faults can develop in one of two ways: either through a ground fault or a short circuit.
Ground Fault Parallel Arc Fault
A ground fault parallel arc fault is possible even without a ground path. This type of arc fault can be cleared by an AFCI or GFCI. Parallel arc faults will have substantially lower RMS current values than a solid, bolted-type fault.
Therefore, a standard 15A breaker may not be able to fix this fault before a fire breaks out.
Short Circuit Arc
Short circuit arcs erode the dielectric layer insulation between the conductors, permitting the development of high-impedance, low-current arc faults that carbonize the insulation and erode the conductor’s insulation further.
The ultimate effect is an increase in current, dramatically increased heat energy, and an increased risk of fire. The maximum current that can flow in a short circuit, parallel arc fault is determined by the system and the arc fault impedance itself.
2. Series Arc Fault
A series arc can happen if the conductor inadvertently breaks while being connected in series to the load. A few instances include a splice, a worn conductor in a cord that has split, or a loose connection to a receptacle.
It is impossible for the arc current in a series arc to surpass the limit set by the load it is servicing. The root mean square current value with an arc in series is lower than that of current without the arc because of extinction and re-ignition.
Series arcs typically don’t provide enough heat to start a fire.
What Kinds Of AFCI Are There?
There are four varieties of AFCI, which vary depending on the application. They are:
- Combination AFCI: To protect branch circuits and the loads connected to them, this AFCI type is most frequently employed in main distribution panels.
- Outlet Circuit AFCI: This device guards against parallel and series arc faults for chord cables plugged into the outlet for sets and power supplies. However, it does not provide arc-fault protection on feed-through branch circuit wires or parallel arc-fault prevention upstream of the device.
- Branch/Feeder AFCI: Installed at the beginning of a feeder or branch circuit, this component resembles a panelboard. It provides parallel arc-fault avoidance for branch circuit wiring, cord sets, and power supply cords.
- Portable AFCI: An extension cord-like plug-in device known as a portable AFCI can be plugged into any regular outlet or receptacle without AFCI protection. The portable AFCI protects any connected appliances or loads.
What Sets AFCIs Apart From GFCIs?
An AFCI operates very differently from a GFCI in a number of crucial respects, including:
- Ground-fault circuit interrupters simply guard against shock, whereas AFCIs are intended to protect against fire.
- The GFCI’s primary function is to protect people from the potentially catastrophic consequences of electric shock that could occur if a ground fault results in some electrical tool or appliance components turning on.
- The AFCI is designed to prevent hazardous arcing faults that can cause an electrical fire and damage branch circuit wire.
- The AFCI and GFCI technologies can coexist and work very well together to safeguard the circuit to the best extent possible.
Why Is An AFCI Needed?
Arc fault fires can start in places like wall cavities, attics, and other places where a smoke alarm won’t be able to detect them until it’s too late, making them particularly dangerous.
Since AFCIs have been proven to be so effective in preventing electrical fires, the National Electrical Code (NEC) mandates their installation in almost every room of newly constructed residences.
Bathrooms, garages, and unfinished basements—all considered non-living spaces—are among the few exceptions. The NEC also requires the installation of AFCIs whenever a room is built, a circuit is created, or even a new outlet is added to an existing house.
If your wiring is old or you want your electrical system to be as safe as possible, you might consider replacing the critical outlets in each circuit one at a time.
How Do I Install An AFCI?
Here is a quick tutorial on installing an AFCI:
- After installing the breaker, fasten the pigtail to the neutral bar.
- The breaker needs to be activated and, if necessary, reset.
- Depress the test button. The breaker should trip as a result.
- Turn off the breaker.
- Connect the load’s hot (black) and neutral (white) wires to the breaker.
- Switch on the breaker.
Avoid making typical wiring errors including distributing neutrals, grounding the neutral across the system, and connecting the load neutral (white) cable to the neutral bar instead of the breaker’s neutral terminal.
The NEC mandates the installation of AFCI for branch circuits with 120 volts, 15 and 20 amps, and single phase in new residential construction. Additionally, having this device helps to protect you from hazardous arc faults that can cause electrical fire threats.