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AFCI circuit breaker connection points (C) Daniel FriedmanArc Fault Circuit Interrupter AFCI Installation, Testing, Recalls
How to wire-up & test a residential-use AFCI, AFCI recalls

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Arc Fault Circuit Interrupter Installation, Wiring, Testing, Recalls:

This article describes how to install AFCIs & how to test AFCIs. We also explain the difference between an arc fault circuit interrupter (AFCI) and a ground fault circuit interrupter. The article also describes AFCI Recall in 2004 & provides a Square-D & Federal Pioneer AFCI Notice. Here are tips for wiring & using AFCI's for arc fault protection to help reduce fire risk in homes.

This article series, adapted and expanded from a US CPSC article on AFCIs is supplemented with additional details and commentary answers most home owner and home inspector questions about installing, testing, and inspecting AFCIs - arc fault protectors in homes.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

How to Install an Arc Fault Circuit Interrupter (AFCI)

AFCI wiring hookup diagramAFCI circuit breakers should be installed by a qualified electrician. The installer should follow the instructions accompanying the device and the panel box.

In homes equipped with conventional circuit breakers rather than fuses, an AFCI circuit breaker may be installed in the panel box in place of the conventional circuit breaker to add arc protection to a branch circuit.

[Click to enlarge any image]

The AFCI installation wiring diagram shown here and others are available from GE, General Electric Corporation and GE circuit breaker distributors.

Homes with fuses are limited to receptacle or portable-type AFCIs, which are expected to be available in the near future, or AFCI circuit breakers can be added in separate panel boxes next to the fuse panel box.

An AFCI hookup wiring diagrams and detailed instructions from GE is available in these GE AFCI INSTALLATION INSTRUCTIONS. Other manufacturer's Arc Fault Interrupter installation guidelines will be similar.

Safety Warning: Do not attempt to work on your electrical wiring, switches, or outlets unless you are properly trained and equipped to do so. Electrical components in a building can easily cause an electrical shock, burn, or even death. 

Even when a hot line switch is off, one terminal on the switch is still connected to the power source. Before doing any work on the switch, the power source must be turned off by set­ting a circuit breaker to OFF or removing a fuse.

See SAFETY for ELECTRICAL INSPECTORS and also see these ELECTRICAL WIRING BOOKS & GUIDES

Three Wire Connections on a Typical AFCI Circuit Breaker

Typically for an electrical circuit to be protected by AFCI, in the electrical panel the circuit hot and neutral wires are connected to marked terminals on the AFCI circuit breaker and a third wire connects the AFCI breaker to the neutral bus in the electrical panel.

You can see my connections in the process of installing an AFCI in the photograph. (Your AFCI device terminals may differ but will be marked)

  1. Load power wire (black) connects to the upper screw marked on this AFCI.
  2. Load neutral wire (white) connects to the center scfrew on this model AFCI.
  3. Coiled white wire that is factory-connected to this AFCI is connected from the AFCI to the neutral bus in the electrical panel.

AFCI wiring details showing the black  and white circuit and white breaker wire connectcions (C) Daniel Friedman at InspectApedia.com

[Click to enlarge any image]

An AFCI circuit breaker, because it is monitoring the neutral wire in the circuit as well a the hot wire, will have three wires connected to it even if it's just a 120Volt single pole breaker. Follow the installation wiring details given by the manufacturer.

Our photos show a Square-D AFCI on which the wire connections are also embossed into the circuit breaker's molded case.

AFCI wiring details showing the black  and white circuit and white breaker wire connectcions (C) Daniel Friedman at InspectApedia.com

On these special circuit breakers you will see

  1. the circuit hot wire, normally black, occasionally red, typically as the second hot wire on a 240V circuit breaker or on a multi wire branch circuit sharing a common neutral wire. (MULTI-WIRE CIRCUITS)
  2. the circuit white wire, the neutral wire for the circuit
  3. a third white wire that is permanently connected to the AFCI breaker and whose other end is to be wired to the neutral bus in the electrical panel to complete the neutral wire part of the circuit that now passes through the AFCI breaker.

Usually this third wire is a multi-strand coiled wire like the one in my photo.

In sum, to install this AFCI you will need to properly connect all three wires: the circuit hot and neutral wires are are connected to screw terminals on the circuit breaker.

The third white wire that is permanently connected to the circuit breaker and whose other end connects to a screw terminal on the neutral bus in the electrical panel.

How to Test an Arc Fault Circuit Interrupter (AFCI)

AFCI circuit breaker at InspectApedia.comUsing the test button on an AFCI

AFCIs should be tested after installation to make sure they are working properly and protecting the circuit.

Subsequently, AFCIs should be tested once a month to make sure they are working properly and providing protection from fires initiated by arcing faults.

A test button is located on the front of the device. The user should follow the instructions accompanying the device. If the device does not trip when tested, the AFCI is defective and should be replaced.

InspectAPedia Notes: How the AFCI Test Button Functions

Because it has been misunderstood and criticized it's worth noting that the test button on an AFCI does not simply force the mechanical internal switch of the AFCI to trip.

Rather, the test button on an AFCI tests the arc fault detection circuitry to be sure that it is working properly, that it will respond to an arc fault, and that the circuitry will in turn cause the mechanical internal switch to open.

This is an important distinction to remember, since the Ground Fault Circuit Interrupter (GFCI) has faced similar criticism. We've certainly found lots of GFCI's which exhibited an error when the GFCI test button was pressed: the button caused the GFCI to trip but the device was defective or improperly wired so that it would not protect the circuit.

Using AFCI indicator tools vs AFCI "test tools" - AFCI Indicators is not recommended

As of September 2008 we have found no test tool that reliably and completely tests the function of an AFCI. Only the integral test button tests the circuitry of the device as well as the trip mechanism. UL classes these "test" devices not as "testers", but as "indicators".

A problem is that some devices used to "inspect" an AFCI, in trying to produce a simulated arc fault condition, may fail to cause the AFCI device to trip even though it is perfectly fine.

Literature from the manufacturer of a popular "test tool" tells the user of the tool to go to the electric panel and use the test button on the AFCI device to make sure it trips. In other words the inspector cannot rely on the separate test tool. For this reason you will see such tools referred to as "indicators" rather than "testers": they are not a complete and reliable test instrument for AFCIs. -- Mike Holt

See important safety and electrical procedure details at AFCI GFCI TESTING & SAFETY

AFCIs vs. GFCIs: What is the difference between an Arc Fault Circuit Interrupter and a Ground Fault Circuit Interrupter?

AFCI Interior components (C) InspectApedia.com Jess AronsteinWhat is the difference between an AFCI Arc Fault Circuit Interrupter and a GFCI Ground Fault Circuit Interrupter? The AFCI should not be confused with the GFCI or ground fault circuit interrupter.

An AFCI is a device intended to prevent a fire. It detects a type of arcing in the electrical circuit that can lead to overheating and a fire.

An AFCI can protect against some types of shock by detecting a short circuit if the short is also affecting an individual, but it is not designed as a shock protector and will not detect all of the same faults as a GFCI.

Photo: a view of the interior components of an AFCI circuit breaker, courtesy Dr. Jess Aronstein.

[Click to enlarge any image]

A GFCI is a device intended to prevent electrical shock. A GFCI will not necessarily detect the type of electrical arcing that can cause a fire.

The GFCI is designed to protect people from severe or fatal electric shocks while the AFCI protects against fires caused by arcing faults. The GFCI also can protect against some electrical fires by detecting arcing and other faults to ground but cannot detect hazardous across-the-line arcing faults that can cause fires.

A ground fault is an unintentional electric path diverting current to ground. Ground faults occur when current leaks from a circuit.

How the current leaks is very important. If a person’s body provides a path to ground for this leakage, the person could be injured, burned, severely shocked, or electrocuted.

The National Electrical Code requires GFCI protection for receptacles located outdoors, in bathrooms, garages, kitchens, crawl spaces and unfinished basements; and at certain locations such as near swimming pools.

A combination AFCI and GFCI can be used to satisfy the NEC requirement for GFCI protection only if specifically marked as a combination device.

InspectAPedia Note: don't confuse this "combination" with the "Combination AFCI described earlier in this article.

While we're discussing the 2008 electrical code changes for AFCI's let's also update ourselves about GFCI's:

2008 Code Changes Affecting Ground Fault Circuit Interrupters GFCI's

This text is now found at GFCI PROTECTION, GFCI CODES

AFCI Square D Arc Fault Circuit Breaker Recall

In 2004 Schneider Electric issued a recall of early model Square D® AFCIs manufactured between March 1 2004 and September 23, 2004 because tests indicated that "... arc detection in these breakers may become inoperable due to an issue with a third party-supplied internal component in the electronic detection unit."

Schneider's letter emphasized in an opening statement that "... Square D Company, the leading manufacturer of electrical equipment, is committed to the safety of our people, our customers, and our products." The company's letter provided additional detail:

While these circuit breakers will continue to function normally, providing short-circuit and overload protection, a small percentage of the breakers may not function as an arc fault circuit breaker (AFCI) and detect a high-resistance low-current arc fault.

The unique role of an AFCI is its ability to detect an electrical arc and shut down a circuit before a fire can start or spread. It is important to note that the affected circuit breaker itself does not pose a hazard.

[The company was concerned about inaccurate and misleading information in the electrical products market and asked that concerned parties turn to them for information regarding their products, including AFCIs.]

The positive responses we have received from electrical inspectors regarding our honest and direct approach to resolving this issue have been appreciated. Many inspectors have been working actively with us as well as their local electrical contractors and builders to minimize the disruption in the construction process.

Those combined efforts have been successful at a vast number of localities.

[...]

We believe that we can accept nothing less than excellence when it comes to safety. For more than 100 years, our customers have associated the Square D brand with industry leadership, safety, quality, and reliability. We intend that our efforts through this AFCI program will continue those qualities.

See FREEZE-PROOF A BUILDING where we describe GFCI protection on heat tape circuits powering heat tapes for manufactured and mobile homes. Similar issues regarding building water entry control are discussed at Sump Pump Inspection.

How to Report an AFCI or other Electrical or Product Failures or Incidents to the U.S. CPSC

Please use the CPSC form found at https://www.saferproducts.gov/CPSRMSPublic/Incidents/ReportIncident.aspx

To comment on or suggest additions to this article use the Comments Box found below, or use our email found at CONTACT

Question: can AFCI's be used in place of GFCI's and vice versa?

(Aug 10, 2015) M Schultz said:

Can GFCIs be used instead of a AFCI?

Can AFCIs replace GFCI?

Why not just have all AFCI breakers or all GFCI plugs?

Reply: no

No M.S.

These devices provide quite different safety protections and cannot be substituted for one another.

GFCI's detect a fault or short from hot to neutral or ground.

AFCI's detect arcing in the electrical receptacle.

I pose that the reason that there is not a combined device in widespread use is cost.

...


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