Basics of AFCI Circuit Breakers

Basics of AFCI Circuit Breakers

A quickSTEP Online Course

? Siemens industry, Inc.

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Trademarks

Siemens is a trademark of Siemens AG. Product names mentioned may be trademarks or registered trademarks of their respective companies. National Electrical Code? and NEC? and NFPA 70? are registered trademarks of the National Fire Protection Association. NEMA? is a registered trademark and service mark of the National Electrical Manufacturers Association. UL? is a registered trademark of UL, LLC. Other trademarks are the property of their respective owners.

? Siemens Industry, Inc. 2017

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Course Topics

Welcome to Basics of AFCI Circuit Breakers. This course covers the following topics:

? Introduction ? AFCI Circuit Breakers ? Intelli-ARC Diagnostic Tool ? Final Exam

If you do not have an understanding of basic electrical concepts, you should complete Basics of Electricity before attempting this course.

? Siemens Industry, Inc. 2017

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Course Objectives

Upon completion of this course you will be able to... ? Define the term arc fault. ? Describe the potential danger of arc faults. ? Identify the some common causes of arc faults in residential and light commercial

applications. ? List the basic recommendations for reducing arc faults. ? Differentiate an AFCI circuit breaker from a standard circuit breaker. ? Differentiate an AFCI circuit breaker from a GFCI circuit breaker. ? Briefly describe the evolution of the NEC? as it relates to AFCI circuit breaker use. ? Differentiate a branch/feeder AFCI circuit breaker from a CAFCI circuit breaker. ? List the residential AFCI circuit breaker types sold by Siemens. ? Describe the diagnostic features built into Siemens AFCI circuit breakers. ? Describe the basic features of Siemens Intelli-Arc Diagnostic Tool. ? Briefly describe how an electrician uses Siemens Intelli-Arc Diagnostic Tool when

troubleshooting a branch circuit.

? Siemens Industry, Inc. 2017

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SITRAIN? Training for Industry

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How-to Video Library - Quick, affordable, task-based learning options for a broad range of automation topics for training or purchase

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This course also describes learning options available from the Siemens SITRAIN USA organization and our global SITRAIN partners. For additional information: usa.sitrain

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Arc Faults

? Siemens Industry, Inc. 2017

Arc faults are electrical arcs between or along conductors or from a conductor to ground. In residential and light commercial applications, these arc faults are not as dramatic as those that occur in large commercial and industrial applications where higher levels of voltage and current are present.

However, it is important to understand that despite the relatively low levels of energy typically associated arc faults in residential and light commercial applications, the danger associated with these faults is significant.

Every year in the U.S. alone tens of thousands of fires resulting in hundreds of deaths, over a thousand injuries, and a billion dollars or more in property damage are caused by electrical failure or malfunction. A significant percentage of these fires are caused by arc faults.

Because of this danger, it is critically important to detect arc faults and to interrupt the flow of current when they are detected. In that regard, this course focuses on arc fault circuit interrupter (AFCI) circuit breakers, with emphasis on Siemens products.

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Common Causes of Arc Faults

? Siemens Industry, Inc. 2017

There are numerous causes of arc faults in residential and light commercial applications. The accompanying graphic shows a few common examples. With these examples in mind, there are some common sense recommendations to consider.

? Do not run power cords in areas where they can be damaged by doors, furniture, equipment, or foot traffic.

? Do not push furniture or equipment up against electrical plugs. ? When unplugging an electrical cord, pull with your hand on the

plug rather than with your had on the cord. ? If blackened plugs, damaged wires, or noisy circuit breakers

are discovered, contact a licensed electrician. ? Take care when using drywall screws, nails, staples or similar

items to ensure that they do not damage electrical conductor insulation. ? When making minor electrical repairs, make sure that you familiarize yourself with good electrical practices. ? When more significant electrical repairs or other electrical work is required, contact a licensed electrician. ? If an arc fault circuit interrupter circuit breaker trips, check for defective power cords and make sure that all light bulbs on the circuit are fully screwed into their sockets. If no problems are found, and the circuit breaker trips again, contract a licensed electrician.

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AFCI Circuit Breakers

? Siemens Industry, Inc. 2017

Like standard circuit breakers, AFCI circuit breakers are designed to open a circuit when an overload or short circuit is sensed. However, an arc fault typically will not generate enough fault current to trip a standard circuit breaker. Only an AFCI circuit breaker incorporates circuitry that continuously monitors voltage and current to arc faults. When it detects an arc fault, an AFCI circuit breaker opens the circuit, stopping the flow of current.

There are two categories of AFCI circuit breakers, branch/feeder AFCI circuit breakers and combination AFCI (CAFCI) circuit breakers.

Branch/feeder AFCI circuit breakers, in addition to providing overcurrent protection, are intended to protect branch and feeder wiring from the damaging effects of line-to-ground arcs and high energy parallel arcs. High energy parallel arcs are line-to-neutral arcs of at least 75 amps.

CAFCI circuit breakers, in addition to providing overcurrent protection, are intended to protect downstream wiring from three categories of arc faults: line-to-ground arcs, high energy parallel arcs of at least 75 amps, and series arcs of at least 5 amps. Series arcs are arcs on a single conductor.

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