# arced out flex



## 1.21gigawatts (Jun 22, 2013)

No egc in this circuit ? You could disconnect and test insulation on other conductors in the system. Sounds like the breakers in the panel may be at the end of use with not triping during a ground faults.


----------



## papaotis (Jun 8, 2013)

ground rod installed at garage, not sure at main building, but ASS-U-ME it is because was told my well know ahj approved


----------



## freeagnt54 (Aug 6, 2008)

papaotis said:


> ground rod installed at garage, not sure at main building, but ASS-U-ME it is because was told my well know ahj approved


Your ground rod would be the GEC, the EGC that 1.21gigawatts is referring to would be the ground wire in your flex.


----------



## chicken steve (Mar 22, 2011)

Assuming your theory of cooked wires in flex is the case, i can understand why you found holes arced in it Papa. 

FMC, like many flexible raceways, usually limited to a 6' rule in the NEC due to it's poor EGC quality. 

Of similar design is all the old BX , predominant on my turf. There have been many instances where it glows away like a toaster element , despite having connection(s) to enclosures one would think would provide a fault path.

It's generally accepted the spiral of flex, once stretched out, can result in 5 or 6X's length, ergo the R factor follows suit.

Meggin' the stuff may be revealing of this as well.

In any case, i take it you've saved Xmas din din for your local diner :thumbsup: ~CS~


----------



## dielectricunion (Nov 29, 2012)

this is unrelated, but, on an old run of greenfield/BX that I had planned to replace, I tried to trip the breaker by arcing to the ground (metal box). I had tested current to ground at 120v so there was an EGC path on the sheath. I arced it 5 or so times and couldnt trip the breaker.

I know this is a lazy and stupid way to find a circuit, but since the box and other parts were going to scrap, i figured it was not a big deal.


----------



## MTW (Aug 28, 2013)

papaotis said:


> ground rod installed at garage, not sure at main building, but ASS-U-ME it is because was told my well know ahj approved


A ground rod does nothing...I repeat NOTHING to aid the overall safety of the system. It sounds like you had a fault somewhere and the impedance of the flex was too high to trip the breaker. Next time, run an EGC with flex.


----------



## aftershockews (Dec 22, 2012)

dielectricunion said:


> this is unrelated, but, on an old run of greenfield/BX that I had planned to replace, I tried to trip the breaker by arcing to the ground (metal box). I had tested current to ground at 120v so there was an EGC path on the sheath. I arced it 5 or so times and couldnt trip the breaker.
> 
> I know this is a lazy and stupid way to find a circuit, but since the box and other parts were going to scrap, i figured it was not a big deal.


Get one of these.


----------



## Vintage Sounds (Oct 23, 2009)

dielectricunion said:


> I know this is a lazy and stupid way to find a circuit, but since the box and other parts were going to scrap, i figured it was not a big deal.


No, it *is* a big deal because breakers are not designed to deal with repeated dead shorts all the time. If you do that then it can potentially affect that breaker's ability to open when it actually counts. Don't just short to the box.


----------



## chicken steve (Mar 22, 2011)

Yeah if one is close enough to the serving Xformer it doesn't take as much AIC to pop a main

But to be honest, it used to be accepted practice to weed out an OCPD via _'grounding out a hot' _

Very much out of vouge these days, from a safety as well as a sensitive equipment standpoint....

~CS~


----------



## papaotis (Jun 8, 2013)

i wsa starting to wonder if was bad timing( the holiday) or no one had a comment on this! doc, didnt need one of those, knew which breakers. like i said in op, i was planning on replacing breakers because i knew they were stressed. maybe if id done it sooner this woulnt have been an issue, BUT then maybe it would have just longer for a problem to arise?


----------



## papaotis (Jun 8, 2013)

i was starting to wonder if it was bad timing( the holiday) or no one had a comment on this! doc, didnt need one of those, knew which breakers. like i said in op, i was planning on replacing breakers because i knew they were stressed. maybe if id done it sooner this woulnt have been an issue, BUT then maybe it would have just been longer for a problem to arise?


----------



## Spark Master (Jul 3, 2012)

The fault current on a dead short, can be 10,000-20,000 amps. I would NEVER do that on purpose.

I've seen phase to phase shorts trip the breaker, and the main. Especially if it's close to the panel, you're asking to blow your face off.


----------

