petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
what is a flying splice?
what is a flying splice?
No junction box....."flying" in midair (often found buried inaccessible toohmy
why would that cause an AFCI to trip?
Exactly, there was likely something else that was never seen as he abandoned concealed wiring when he assumed there was a flying splice somewhere, but the flying splice itself likely was not a problem for the AFCI breaker.baffles me.
Wouldn't in itself cause AFCI to trip, but maybe added stress pulling connection apart?
Personally, if I find a flying splice on a job it sets off a red flag. Makes me scrutinize everything else on the property.
Now you have given us much better reason to just abandon it even if you don't know exactly what was concealed or even if AFCI were not involvedLoose connection under wire nut assuming wire nuts were used is the most likely cause.
PS the home had aluminum wiring.
View attachment 9572
View attachment 9573
*puts on electri-snob hat*
A concealed flying splice will cause the AFCI to trip because any electrician that would conceal a flying splice probably didn't twist the splice together tight enough, nor installed the wirenut properly, and probably nicked the conductors while stripping the sheathing and possibly left it near the stud so the drywaller drove a screw through the whole thing anyway.
That is still a AFCI trip condition because of a bad connection and not because it isn't in a junction box.
It is also questionable whether or not a loose connection will even trip an AFCI, search this site for discussions on glowing connections and you will find AFCI generally will not recognize that condition, yet it is supposedly one of the things they are in existence for:huh:
....by someone other than a manufacturer of AFCI devices.I have played with them and made lots of sparks (intentionally) under a load and the AFCI held fast. I was told that the duration of the sparks weren't long enough to trip the breaker. The little voice in my head was saying 'yeah, right'.
Like many others, I really doubt the effectiveness of the arc sensing devices. I haven't looked yet, but I wonder if there is a YouTube video that shows an AFCI actually tripping on an intentionally created arc.
....by someone other than a manufacturer of AFCI devices.
Sorry, you didn't complete your last sentence.:happyyes:
I wonder if anyone here has actually found a real incipient hazard that was detected by an AFCI that tripped.
We find them all the time that GFCI's detect.
I am talking about in real life. As an example, a customer calls with an AFCI that is tripping and the electrician actually locates a place on the circuit or in a device that has physical evidence of an arc where one should not have been.
I will give you one out of two for that. The plug was probably a series arc, which the AFCIs are not good at. But it might have been a parallel arc as the receptacle melted.
But the screw was definitely a ground fault which ordinary GFCI or even GFP protection would catch. And an AFCI without GFP would not have.
Literally it was the first 6' of the branch circuit before the GFCI receptacle (the line side), it would not have been protected by the GFCI receptacle only the AFCI breaker.
When I was a teen, we removed carbon from D cells, put 2 nails in a piece of wood, the nails in salt water. The salt water as series resistance allowed making an arc light. That should be a good series arc ...Eaton pushes their AFCI's hard.
The most credible YouTube video that I can find is by them, but then again, they are the interested party: http://www.youtube.com/watch?v=uqZfuRDNz04
There will always be a nagging doubt over efficacy of AFCI's, simply because to test them you have to safely produce a real and sustained arc on demand, which is a tall order..
The only more or less reliable testers that I know of are the Ideal 61-164 and 165, and even those don't produce an arc-- just waveforms that imitate the line noise characteristic of one.