Arc breakers....

[mrcaptainbob]

Didn't want to hi-jack Jack-of-all-Trades post on this. HayZee, you affectionatley referred to the 'new fangled arc breakers'...what are these?

[OMKEN]

I am a Master electrician and will tell you that my personal house has these in my loadcenter for all 15 and 20 amps 120V circuits. Simply put.... A typical circuit breaker is designed to trip the circuit in either of the following 2 conditions. The first a short circuit (usually the current carrying conductor..hot wire... either shorts out to the neutral... white wire... or directly to ground) which is called an instantaneous trip. The other is a thermal overlaod which is heat buildup on the conductors over a short period typically due to overloading the circuit. Example of this is powering a 1500 watt hair dryer and an electric iron on the same 15A circuit.

OK...so what does an AFCI do that is different. It protects for the two situations listed above PLUS for an arc fault condition. Arc Faults could be a frayed extension cord or a damaged piece of Romex behind a wall caused by a nail or metal staple that accidently pierced the romex cable. These arc faults will intermittently spark ( not enough to trip a typical breaker ) but enough to build up enough heat to start a fire over time. An AFCI, through it's electronics will sense these arc faults and trip the breaker to prevent a potential fire.

Yes they cost more than a typical breaker....but after I saw a demonstration of how these really work, I sleep a whole lot better at night knowing that these are protecting the circuits in my kid's bedrooms.

Hope that helps !

[HayZee518]

CaptBob read omken's response. covers all bases. arc-fault breakers.

[tom31415926]

Greetings,

I believe that I understand the functions of these two types of breeakers.

The GFCI detects and trips on ground fault current; that is, if any current supplied by the circuit does not return on the corresponding neutral.

The AFCI detects the characteristics of an arc in the circuit, and trips on that.

I searched the web concerning AFCIs a while back and recall some mention that a particular GFCI outlet "was not for use" in a circuit protected by an AFCI. Or was that vice versa? I can't recall.

Anyway, I'd like to know if there are any compatibility issues if both types of protection are desired.

I guess that the best way to go would be to use AFCI breakers and put GFCI outlets where desired. Any thoughts?

Tom

[mrcaptainbob]

Great info! What an education this forum presents! Thanks...

[OMKEN]

Tom,

Two totally different types of protection, but yes they can and should be combined under the right conditions. Ground Fault breakers provide "people" protection in that they will trip if 5ma or more is leaked to ground. Arc Fault, as I described earlier protects the branch circuit conductors from overheating due to arc fault conditions.

So by all means you can and should use both in wet / outdoor locations where ground fault protection is required. Not sure they are released for sale yet, but the people who first introduced ground fault breakers.. Eaton / Cutler-Hammer are coming out with a combination AFCI/GFCI breaker. If not available yet, you can always use an AFCI breaker and a GFCI receptacle.

Good luck !