AFCI troubleshooting

Poweranytime

FL EC
Location
Nature coast Fl
Occupation
Master EC
Probably for all you service and punch list folks. Trying to find some thoughts and tactics to find root cause of problems with an arc fault circuit without having to open a bunch of back stabbed devices, fans, lights etc. This is of course when it's already verified that it's not the breaker.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Troubleshooting is a process of elimination. You may well have to check every connection; start with the easiest

The best intermittent-problem tool is a high-wattage incandescent bulb in line with the load wire at the breaker.

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You will likely have to tap or wiggle devices you suspect, while watching the bulb for variations of brightness.

Either have a fast helper monitor the light, or use a receptacle and extension cord to carry the light with you.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
This would be taking the afci out and putting a regular breaker in while doing the test you speak of?
I hadn't thought of it, but now that you ask, I'd say yes, if the AFCI still won't hold.

Do your AFCIs show that an arc fault is what it detected and responded to?
 

ActionDave

Chief Moderator
Staff member
Location
Durango, CO, 10 h 20 min without traffic from wing
Occupation
Licensed Electrician
... This is of course when it's already verified that it's not the breaker.
How do you know it's not the breaker? There is almost zero chance 120V is sustaining an arc. My test procedure is to swap the breaker out with a GFCI to rule out any wiring errors and then start replacing breakers with the newest model that has more filtering programmed into it.
 

ramsy

Owner/Operator
Location
LA basin, CA
Occupation
Service Electrician 2017 NEC
I've been surprised the last few months by different experiences with AFCI's.

Case 1:
1P GE 15A AFCI trips on switched outlets, until un-tying 20A plug neutrals from 15A lighting neutrals at half-hots.

Later, a painter's spray compressor trips GFCI outlet only, not this AFCI breaker feeding garage & all half hots. Owner brings compressor ext.cord to other side of wall inside house at switched half-hot outlet, which immediately trips the panel AFCI, no longer monitored by garage GFCI on same circuit.

Client then plugs problem compressor into kitchen's Leviton AGTR1 Dual Function AFCI/GFCI outlet on STD breaker, and it holds all day long, with no complaints from 2 separate GE AFCI's in that panel.

For other clients, this same model AGTR1 outlet demostrated extraordinay sensitivity with cord damage, smoldering wires, devices & upstream bus smoldering. I had no explanation, except maybe some kind of proprietary filters not available in most AFCI breakers yet.
 

Poweranytime

FL EC
Location
Nature coast Fl
Occupation
Master EC
How do you know it's not the breaker? There is almost zero chance 120V is sustaining an arc. My test procedure is to swap the breaker out with a GFCI to rule out any wiring errors and then start replacing breakers with the newest model that has more filtering programmed into it.
So that is an interesting take. Usually we will steal an AFCI from another circuit in the panel that is clear to rule out Breaker or downstream then proceed.
 

ramsy

Owner/Operator
Location
LA basin, CA
Occupation
Service Electrician 2017 NEC
Case 2:
Client burns up 15A NM cable after 40yrs of 20A laundry loads when Wash & dry ran together. Client calls plumber who explodes 15A Zinsco, while forcing closed breaker on energized bus during this short-circuit cable condition.

An electric oven cable was found abandoned under house by remodelers. So laundry gets 50ft 6/3 cu with concentric EGC, wires terminated to #10 stranded at both 2P 20A breaker, and 2 AGTR2 devices at end of line. Low impedance with utility.

A few weeks later both AGTR2's nuisance trip with laundry appliances unplugged, no un-listed gadgets from Amazon, no other occupant activity, and a clean branch ckt tested @ 2G-ohm, with replacement breaker on pristine solid-copper bus.

Client waits for 100°F heat to dissapate in the evening, nuisance trigger resolves itself, laundry runs normally, and client phones to cancel the trouble call.

While this Leviton AGTRx outlet can select out some appliance troubles downstream, in superior fashion to rival AFCI and GFCI functions, its not at all superior with regard to selecting upstream events at utility magnitudes, which can play electromagnetic-pulse warfare with unshielded electronics.
 
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Poweranytime

FL EC
Location
Nature coast Fl
Occupation
Master EC
I hadn't thought of it, but now that you ask, I'd say yes, if the AFCI still won't hold.

Do your AFCIs show that an arc fault is what it detected and responded to?
Usually it is older AFCI breakers and in our area the majority are ch afci. We of course replace with the latest and greatest but we usually don't have indication on the breaker
 

Poweranytime

FL EC
Location
Nature coast Fl
Occupation
Master EC
Case 2:
Client burns up 15A NM cable after 40yrs of 20A laundry loads when Wash & dry ran together. Client calls plumber who explodes 15A Zinsco, while forcing closed breaker on energized bus during this short-circuit cable condition.

An electric oven cable was found abandoned under house by remodelers. So laundry gets 50ft 6/3 cu with concentric EGC, wires terminated to #10 stranded at both 2P 20A breaker, and 2 AGTR2 devices at end of line. Low impedance with utility.

A few weeks later both AGTR2's nuisance trip with laundry appliances unplugged, no un-listed gadgets from Amazon, no other occupant activity, and a clean branch ckt tested @ 2G-ohm, with replacement breaker on pristine solid-copper bus.

Client waits for 100°F heat to dissapate in the evening, nuisance trigger resolves itself, laundry runs normally, and client phones to cancel the trouble call.

While this Leviton AGTRx outlet can select out some appliance troubles downstream, in superior fashion to rival AFCI and GFCI functions, its not at all superior with regard to upstream events at utility magnitudes, which can play electromagnetic-pulse warfare with all unshielded electronics.
Wow..I haven't had too much experience with afci/gfci devices. Most of the time we just breaker the circuit but I am not a fan of leviton in any case. We use P&s
 

Poweranytime

FL EC
Location
Nature coast Fl
Occupation
Master EC
Case 2:
Client burns up 15A NM cable after 40yrs of 20A laundry loads when Wash & dry ran together. Client calls plumber who explodes 15A Zinsco, while forcing closed breaker on energized bus during this short-circuit cable condition.

An electric oven cable was found abandoned under house by remodelers. So laundry gets 50ft 6/3 cu with concentric EGC, wires terminated to #10 stranded at both 2P 20A breaker, and 2 AGTR2 devices at end of line. Low impedance with utility.

A few weeks later both AGTR2's nuisance trip with laundry appliances unplugged, no un-listed gadgets from Amazon, no other occupant activity, and a clean branch ckt tested @ 2G-ohm, with replacement breaker on pristine solid-copper bus.

Client waits for 100°F heat to dissapate in the evening, nuisance trigger resolves itself, laundry runs normally, and client phones to cancel the trouble call.

While this Leviton AGTRx outlet can select out some appliance troubles downstream, in superior fashion to rival AFCI and GFCI functions, its not at all superior with regard to upstream events at utility magnitudes, which can play electromagnetic-pulse warfare with all unshielded electronics.
Wow..I haven't had too much experience with afci/gfci devices. Most of the time we just breaker the circuit but I am not a fan of leviton devices in any case. We use p&s exclusively.
 

romex jockey

Senior Member
Location
Vermont
Probably for all you service and punch list folks. Trying to find some thoughts and tactics to find root cause of problems with an arc fault circuit without having to open a bunch of back stabbed devices, fans, lights etc. This is of course when it's already verified that it's not the breaker.
Troubleshoots start with knowing the target....

afci, gfci, lcdi, agtr, or any other 'enhanced' OCPD and/or outlet share one common operational component , which can only detect one distinct wiring abnormal condition , with regard to it's ma setting.

~RJ~
 

Poweranytime

FL EC
Location
Nature coast Fl
Occupation
Master EC
The target is a clear path and that is true a fault condition on any path would result in tripping. I have fixed more 100 of these circuits in the last 15 or so years and always find it. Some easy frayed cord near a bed, cracked receptacle or the homeowner just hung a fan or light. Then there's the backstabbing receptacle or switch that's cracked or wiggled loose or an egc that has decides to move a c hair over 15 years and touches a neutral terminal on a recept. Just wish there was some way to ping it without opening a bunch of stuff in a furnished house. Remember how much crap Americans have shipped from communist China
 

Fred B

Senior Member
Location
Upstate, NY
Occupation
Electrician
Probably for all you service and punch list folks. Trying to find some thoughts and tactics to find root cause of problems with an arc fault circuit without having to open a bunch of back stabbed devices, fans, lights etc. This is of course when it's already verified that it's not the breaker.
It would depend on the circumstances of the tripping event. Lighting circuit, SABC, general use receptacles, direct wire appliance? As mentioned start with most obvious and move on from there. Then isolate sections of circuit, look for improperly done jboxes, etc.
Had one that was a puzzle not related to loose connections, after much searching finally isolated to a outside LED carriage light, remove fixture and replaced with a porcelain base and bulb, breaker holds, moved a similar carriage light into this location, breaker holds, put the original fixture back in that location, breaker trips, replaced with new fixture, breaker trips.
Another one called in for an AFCI breaker tripping. First confirm not breaker by swapping, then replace with standard breaker, it holds, gfci breaker holds. Starting tracking by what was last thing done onto the circuit, most likely as breaker had been holding for a good period prior. Reported that the trim work on cathedral ceiling was just done, so isolate that section, breaker holds. Found a gun finish nail hit the NM at the fixture box clipping the hot conductor on the outside edge not by the ground. Fortunately there was enough slack to get the damaged conductors pulled into the fixture box and repaired, no more tripping.
Weirdest one I've seen, and don't know how it happened, not on AFCI, not required at time of installation, got a call to move some wires for some carpentry. At some point in time, someone had nailed on some trim with 2 and1/2" finish nails and hit the hot side of a NM cable dead on and actually pierced the copper through the center, had been that way for years and operating.
 

romex jockey

Senior Member
Location
Vermont
Just wish there was some way to ping it without opening a bunch of stuff in a furnished house
TS'ing can always result in such unfortunate circumstances ......i'm often torn at which 'end' to start with , yet have had some success with older wiring starting with the panel........deenergize and disable the MBJ ......ring it out........unplug everything in the house.......ring it out. IF there's a difference, take one noodle at a time off the N-bar....ring it out one at a time.....I'm sure you see where i'm going w/this ~RJ~
 

Fred B

Senior Member
Location
Upstate, NY
Occupation
Electrician
The target is a clear path and that is true a fault condition on any path would result in tripping. I have fixed more 100 of these circuits in the last 15 or so years and always find it. Some easy frayed cord near a bed, cracked receptacle or the homeowner just hung a fan or light. Then there's the backstabbing receptacle or switch that's cracked or wiggled loose or an egc that has decides to move a c hair over 15 years and touches a neutral terminal on a recept. Just wish there was some way to ping it without opening a bunch of stuff in a furnished house. Remember how much crap Americans have shipped from communist China
I know of nothing other than process of elimination. Depending on level of issue causing the tripping maybe a FLIR might be able to see the point of failure if sensitive enough? IDK.
 

Poweranytime

FL EC
Location
Nature coast Fl
Occupation
Master EC
Oops quick visits and costs on both customers and us for a simple reset. Florida has all kinds of utility fluctuations. P&s is just a better device imo
 

ramsy

Owner/Operator
Location
LA basin, CA
Occupation
Service Electrician 2017 NEC
Roger that, and do I understand correctly there's no difference between P&S & AFCI breakers dealing with utility issues?
 
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