A GFCI Guy joins the community.

[Spieg]

All my GFCI are built into circuit breakers in the power cabinet in my basement. Can't even get cell service down there, so I doubt RFI is even a valid concern in this case.

 

[SoggyNW]

Sorry, it’s late where I am. I have to admit it’s concerning to hear a residential electrician ask this question. You certainly must know the difference since code requirements are very different.
They are completely different and no, it is not redundant because they have completely different functions. Simplified, GFCI’s are detecting a difference in current between the hot and neutral, if this difference becomes dangerous ( around 5mA but before 6mA) the the circuit is interrupted. AFCI’s are designed to detect arc flash within a circuit. It does this by reading or monitoring the “noise” created when arcing occurs. Because our current (North America) operates at 60 hertz is possible to compare the harmonics on a circuit and detect a difference. The two devices couldn’t be more different. However, it’s possible one day that (wink wink) someone will come up with a combination device to do both.

Sorry I didn't mean to say that I was ignorant of the way they work. Of course they each have their application in the code and we use them as required, I don't take that lightly. My experience in the field is that anytime we have an AFCI breaker followed by a GFCI device, the breaker will trip on a GFCI test before the GFCI itself will. That doesn't mean we are covering all our bases, And I don't want to put out bad information because I'm miss understanding the details so I'm going to stop here.

 

[Steve Zee]

Sorry too that I misunderstood your question. In the case you described, it could be that the arc is past the GFCI (on load side) and the circuit is arcing to a source other than the Neutral. This causes the GFCI to trip. However, if the arc is on the load side of GFCI and the arcing is between the hot and neutral then the GFCI does nothing. AFCI's are great at protecting heat and fire hazards because they can detect arcing between HOT and Neutral or Ground that may be hidden behind walls or conduit. But have nothing to do with safety from electrical shock... well, not directly. Hopefully you can see what I'm getting at and this makes more sense.

 

[Jeeperz]

Ferrite cores/chokes worked well for a t5 fixture I used to have...

I'm interested in these. I have replaced more GFCI outlets that failed for no good reason, some quit working without anything on the circuit. I 100% refuse to use GFCI for anything important, they are very unreliable, even the premium ones from home Depot.