DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (
-   Electrical (
-   -   Afci & gfci (

secutanudu 10-11-2009 09:10 PM

Afci & gfci
I understand the difference between GFCI and AFCI.

I have GFCI protected a few circuits in my house, particularly the ones that lead to outside fixtures, basement receptacles and bathrooms. These circuits also have some other stuff (including my master bedroom lighting/outlets). I did this by installing GFCI outlets near the beginning of each circuit (I didn't put in GFI breakers).

I am thinking of getting some AFCI breakers for the living area of my house, since the wiring is very old and there is a decent potential for arcing.

Is it OK to put an AFCI breaker on a circuit that also is GFCI-protected via a GFCI receptacle?

Is there any reason not to replace ALL breakers with AFCI?


joed 10-11-2009 10:57 PM

It is fine to put the AFCI onthe GFCI circuits.

secutanudu 10-12-2009 12:39 PM

Thanks. Is there anything in particular that you should NOT protect with either GFCI or AFCI?

I know things like a fridge, computer (i think) should not be on GFCI, but is it basically ok to put everything on AFCI?

gregzoll 10-12-2009 01:31 PM


Originally Posted by secutanudu (Post 339619)
Thanks. Is there anything in particular that you should NOT protect with either GFCI or AFCI?

I know things like a fridge, computer (i think) should not be on GFCI, but is it basically ok to put everything on AFCI?

In theory it is not, since they would fight against each other, causing Nuisance trips.

secutanudu 10-12-2009 01:35 PM

oh, how would they fight against each other? Assuming there is no arcing or ground fault, wouldn't they both stay closed?

gregzoll 10-12-2009 01:42 PM

Because they both use electronics, and any time there is a chance that the GFCI would see a possible short to ground or Neutral, the ACFI would see the short to Neutral as a potential problem. The key is to not mix the two, and my personal opinion, is to use as the NEC code states, not change things. Now, if there is a chance that someone comes up with a dual use ACFI/GCFI device, they will be rich.

JonboyAU 10-12-2009 04:27 PM

AFCI and GFCI Protection
An AFCI can be used in conjunction with GFCI protection to provide both arcing fault protection as well as 5mA ground fault (people) protection. A common way to provide both types of protection is to use an AFCI circuit breaker and a GFCI receptacle. AFCIs can also incorporate 5mA GFCI protection into the same package. This solution for AFCI and GFCI on the same circuit can be useful where the circuit design requires both types of protection or where the installer (or user) wants to have both types of protection.
Top of page
What is the difference between and AFCI and Ground Fault Circuit Interrupter (GFCI)?
There is a major difference between the functioning of an AFCI as compared to a GFCI (Ground Fault Circuit Interrupter). The function of the GFCI is to protect people from the deadly effects of electric shock that could occur if parts of an electrical appliance or tool become energized due to a ground fault. The function of the AFCI is to protect the branch circuit wiring from dangerous arcing faults that could initiate an electrical fire.
AFCI and GFCI technologies can co-exist with each other and are a great complement for the most complete protection that can be provided on a circuit.

philS 10-12-2009 04:35 PM

What about the problem of any kind of large motor tripping AFCI breakers? I can tell you from personal experience that I can't run my chopsaw on a circuit that's AFCI protected (Sq D Q panel). I'd expect vacuum cleaners, 120 V air conditioners, even large fans to be just as much of a problem.

gregzoll 10-12-2009 04:55 PM

That would be a nuisance trip caused by the ACFI thinking that there is a arc, which the motor brushes do cause. Also, keep in mind, that the circuit may already be within its limits, when the trip occurs. There are just too many factors here for each home owner, for any one person to determine why your circumstance is different then others.

gregzoll 10-12-2009 04:56 PM

That is what I was wondering about, with the combo circuit. That would defiantly work in a "Wet" environment, but costs come into play with anytime the breaker goes nuts up, you pay more.

philS 10-13-2009 05:22 AM

Gregzoll - Was that my situation you were referring to? If so, I had nothing else plugged into the circuit when the chopsaw tripped the AFCI, not even a light. When I mentioned it to my pals at my electrical supply store, they laughed and said, "Yup, take out the AFCI as soon as the inspector signs off, put it back in whenever he's due to come back". I've still got trim to do in the bedroom. Once that's done I'll put the AFCI back in, because basically I like the extra safety factor, but if the vacuum cleaner trips it, it's going to sit on top of the water heater until next time I get inspected.

Scuba_Dave 10-13-2009 07:00 AM

There are some vacuums that will trip an AFCI
They have (supposedly) since fixed that problem
Not sure if Vacs were fixed or AFCI

Square D had a recall on AFCI breakers - blue button (not all), mine went back


sold the AFCIs between March 2004 and September 2004

All times are GMT -5. The time now is 06:01 PM.

vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

Search Engine Friendly URLs by vBSEO 3.6.1