# Combination Arc-Fault Breakers?



## calimurray (Apr 29, 2007)

Has any one heard of this? Combination Arc- Fault breakers Required by 2008 electrical code. We have to install these on this job in Arlington Hts. Il. , the inspector says they are required by the 2008 NEC.

The supply house has heard of them twice. Us being second. Supposably they have blue trip reset button and what is there purpose I mean how are they different from regular AFCI breakers?


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## calimurray (Apr 29, 2007)

Combination AFCI circuit breakers provide an added dimension of safety for homeowners by sensing and responding to both parallel and series arcing incidents. Series arcing is often associated with damaged devices or cord sets. A series arc is an arcing incident across a break in a conductor. A common example is a cut across one of the two wires in a lamp cord, with a dangerous arc forming in the gap. Combination AFCI circuit breakers detect the arcing condition and turn off the circuit, thus providing the enhanced protection.
View an animated example of a series arc and a parallel arc by clicking this link - www.afcisafety.org.



I guess I found an answer, any one have good or bad experiences with these?
http://www.afcisafety.org


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## JohnJ0906 (Jan 22, 2007)

FWIW, the combination AFCIs are required under the 2005 NEC. The requirement wasn't set to take effect until January 1st, 2008. See 210.12(B), last sentence, in the 2005 NEC.


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## nap (Dec 26, 2007)

How about we use the UL definition because it is not what calimurray posted.



> • *Branch/Feeder AFCI *– This device is installed at the origin of a branch circuit
> or feeder, such as at a panelboard, to provide protection of the branch circuit
> wiring, feeder wiring, or both, against unwanted effects of arcing. This device
> also provides limited protection to branch circuit extension wiring (e.g. cord
> ...





> downstream branch circuit wiring, cord sets and power-supply cords.
> ​​




the intent is to provide arc-fault protection to both the premises wiring for the concerned branch circuit as well as the cords of the devices plugged into the concerned circuit.

devices that are not "combination" were designed to protect one or the other but not both.

this is a note of explanation from UL:​

> The NEC and AFCIs
> 
> During the revision process for the 2002 NEC there were several proposals to
> revise Sec. 210-12 to require both a branch/feeder and outlet circuit AFCIs in
> ...





> entire branch circuit.”
> ​​


​​


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## waco (Dec 10, 2007)

I must admit, I can't envision a technical reason why a device that can sense arcing in a branch circuit wouldn't sense arcing in something attached to that circuit, so, I'm confused.

I suspect it is about money.


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## nap (Dec 26, 2007)

I don;t either. Dang, I'm still trying to figure out how they work at all.


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## frenchelectrican (Mar 15, 2007)

Nap .,

I did see them work { AFCI } They are pretty close to simauir to the GFCI breaker fuctionwise but a nice gotcha is they come in two verison parallel arc fault or combation which it mean both parallel and series arc fault.

Yes they do have somesorta of CT coil inside the breaker and with whatyacallit circuitboard.

I have limited experince with this due my State ( Wisconsin ) have optional use of AFCI ( our code did push the AFCI requriement back to 2011 Code cycle :huh and some are fine and some are peice of crap.

To trobleshooting them they are dang picky and it is not 100% reibale due some new items show up and get it screwup.

Merci,Marc


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## nap (Dec 26, 2007)

Luckiliy (to date) Indiana has not accepted them yet although the '08 code takes effect in a couple weeks. Haven't heard if they excepted them out yet.

I have had folks try to explain exactly how they work but the problem is tha person did not really know how they worked and they were trying to explain things to a person that did not know how they worked.

basically we had a conversation with a LOT of speculation and no facts to support any of it. 

I was told many moons ago that these things somehow read the waveform of the power. An arc will cause the waveform to change to some predictable form and that is what the circuit board "sees" and utilizing whatever disco method involved (sounds like a small solenoid type unit), the unit is de-energized.

So, one of my many questions is: often, when you plug in a device/appliance with the switch on (loading the circuit), a recep will arc. Is that going to trip the dang things?


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## 2towbot (Nov 19, 2008)

Yes it will trip the Device , they can be very very sensitve.
I have had arcs detected in Filaments on luminaires


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## nap (Dec 26, 2007)

Hoping hoping hoping that Indiana excepts AFCI out of the code again.

they sound like real PITA's


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## macmikeman (Jan 23, 2007)

Honestly, I have had to put in several dozens of them so far this year and haven't seen any difference in problem rates from the older style of afci breakers. I have had maybe one or two times I had to go find the neut/ground connection mistake. One I remember was at light fixture -neutral wire pinched by mounting screw on incandescent ceiling light. Other one was ground wire touches neut at receptacle outlet. Other than that- zero problems. I have accepted them to the same degree as bedroom smoke alarms, - required, but occasionally a pain in the rear....


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## BWA (Jan 20, 2010)

waco said:


> I must admit, I can't envision a technical reason why a device that can sense arcing in a branch circuit wouldn't sense arcing in something attached to that circuit, so, I'm confused.


What I just read said the difference is in the AMPs of the fault. They say corded items have lower AMPs for such faults than the branch circuit.


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## BWA (Jan 20, 2010)

nap said:


> So, one of my many questions is: often, when you plug in a device/appliance with the switch on (loading the circuit), a recep will arc. Is that going to trip the dang things?


"Depends."


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