New Arc Fault Circuit Breakers
Summary: Electrical fires happen every day in the United States because of electrical shorts that produce intensely hot arcs. An arc fault circuit interrupter senses these arcs and stops them, making them smarter than traditional circuit breakers.
Related Articles: circuit manufacturers, circuit interrupters
DEAR TIM: There was a house fire on our street last week. The fire investigators traced the cause to a short in an electrical wire. I am terrified that a fire can start in my own home without warning. Why didn't the person's circuit breaker trip as soon as the wire shorted? Is there a way to prevent fires caused by short circuits in electrical wiring? Laura M., Bellevue, PA
DEAR LAURA: Your neighbor's fire was just one of the 115 +/- electrical fires that happen each day in the USA. These fires cause hundreds of millions of dollars in damage, injure thousands of people and are responsible for the deaths of hundreds of people each year. I can see why you are terrified. Ask any firefighter and he will tell you that electrical fires are non-discriminatory. They can strike anywhere and at any time.
The traditional circuit breakers in your neighbor's house did not prevent the fire for a simple reason. They are not designed to sense arc faults. Traditional circuit breakers are actually designed to protect just the wire behind the walls and the switches and outlets that they are connected to. The circuit breakers are designed to trip when they sense a short that causes an avalanche of electricity coursing through a circuit. They also will trip when a constant massive amount of electricity passing through the circuit causes a heat buildup within the breaker. Traditional breakers are not designed to protect lightweight appliance wires and extension cords that are plugged into wall outlets.
Fire producing arcs can occur in wiring before traditional breakers react. Electrical manufacturers recognized this problem and decided to attempt to stop as many of these electrical fires as possible. The result of the hard work of many is a new arc fault circuit interrupter breaker. These devices work and act like a traditional circuit breaker except that they are smarter. Many of these new devices contain small filters and logic devices that allow them to sense an arc just as it is about to produce the sparks and intense heat. If arcing conditions are present, then the breaker trips instantaneously.
Do not confuse these devices with the personal protection ground fault circuit interrupters (GFCI) that have been around for over 30 years. The GFCI circuit breakers, at the present time, do not have the capability to sense arcs.
The new arc fault circuit breakers are identified in section 210-12 of the 1999 edition of the National Electric Code. Beginning January 1, 2002, they were required to protect branch circuits that serve residential bedrooms. These areas of the house have been identified as the source of many electrical arc related fires. The state of Vermont has taken a slightly more aggressive stance. They are requiring that these new life saving circuit breakers be used in all circuits that feed residential living areas. Their regulation went into effect on January 1, 2001.
These new arc fault breakers can be purchased now in every state in the USA. These breakers are the same size as your existing traditional circuit breakers. The new arc fault breakers cost about $25 - $50 each depending upon manufacturer, but it is a very small price to pay for peace of mind. An experienced electrician can install a new arc fault breaker in a matter of minutes. It actually takes longer to remove and replace the cover to the circuit breaker panel than it does to switch out the breaker.
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Comments:
Kevin Jones 04 Dec 2007, 07:09
I have moved into a new home, and
I have one arc falt breaker that keeps on tripping. The builder has sent out (twice) the electrician who wired the house and they cant find anything wrong. What should I do.
Richard Thomas 04 Dec 2007, 07:34
I have just installed new outdoor lighting and outlets on two circuits
using a 3 wire plus ground outdoor cable. Can I protect both circuits with
arc fault breakers in the main supply panel?
AsktheBuilder 04 Dec 2007, 07:44
Ask the builder to find a new electrician who knows how to troubleshoot.
The electrician you have is obviously out of his zone of comfort and
knowledge.
AsktheBuilder 04 Dec 2007, 07:49
Richard,
Since these are outdoors, I would prefer you use Ground Fault Circuit Interrupter breakers, not arc fault. The folks who author the National Electric Code most likely would agree.
ron 07 Dec 2007, 16:23
I have a new home and the electrician installed "arc fault breakers". Since
I connected my thread mill it jumps sometimes when I start. COuld it be
that these breakers are not intended to work with electric motors? Thank
you. Ron
AsktheBuilder 07 Dec 2007, 16:56
Ron,
This is the first I have heard about a reaction like you describe. I would test with an extension cord to a circuit that has a normal breaker.
JAMES MATHIS 11 Dec 2007, 21:25
I AM LEARNING ABOUT ELECTRICAL WORK AND I WOULD LIKE TO BE ON YOUR E-MAIL
LIST.
THANK YOU
RRH 12 Dec 2007, 07:13
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dennis 25 Dec 2007, 19:29
I have a new home and when i turn on the light in my bath room the arc
breaker for 2 of my bedrooms trips,however the light in the bathroom stays
on.When i reset the breaker and leave the bathroom light off as soon as i
put a load on any of the bedroom outlets i trip the arc breaker. Have any
ideas?
AsktheBuilder 26 Dec 2007, 07:32
Dennis,
Yes, since you say it is a new home, file a warranty claim. There is obviously a small short in the circuit. View all comments |



