Not Sold on AFCI's

[templdl]

I have had to trouble shoot one house that started tripping after homeowner lived there for one year. It turned out to be a broken neutral in the ceiling fan j-box. Fan had very heavy usage in the summer prior to fault; it appeared fan vibration cause a breakage in faulty wire install.

In all reality how long did it take you to find it? It's often like trying to find a needle in a haystack, finding something that is so little but causes so much grief.
I'm impressed.

 

[kbsparky]

Along with owning/using a megger comes knowing how to use it, what to disconnect from the circuit being tested, how and why to make resistance tests at low test voltage before performing on a high test voltage reading. The power strip, and pretty much anything plugged into receptacles should be unplugged when testing the premises wiring. ....

You missed my point entirely.

My assertion is that many times nuisance tripping can be caused by transient surges originating from the outside, and then the surge-protected power strip shunts it out. This trips out the AFCI or GFCI device.

So many have said you have to test your circuits, and sometimes that involves using a megger. Fair enough.

But unless you unplug the surge power strip, using a megger is useless. Using a surge power strip downstream from a AFCI or GFCI device can and will cause nuisance tripping. And testing the wiring without removing such items first is a big waste of time.

My discussion with ELA alludes to this condition, one in which he refuses to acknowledge.

I don't believe that any mini-circuitry contained within that tiny breaker can be sufficient to protect the rest of the circuit from transient surges. Internal circuitry, maybe, but not the whole circuit! Besides, things like GFCI receptacles don't seem to have such features, and surge strips plugged into them also cause nuisance tripping.

Just this week, had another customer complain about nuisance tripping of only ONE of his AFCI breakers. He has several, but guess which one has the computer surge-power strip plugged in? You guessed it, the one that is tripping out. Coincidence? Maybe.

But I'd be willing to bet that removal of that surge strip will solve his nuisance tripping problems.

As stated earlier, I won't waste my or my customers' time troubleshooting until such things have been removed and the condition continues to be a problem. Then and only then it may be time to break out the megger ...

 

[templdl]

You missed my point entirely.

My assertion is that many times nuisance tripping can be caused by transient surges originating from the outside, and then the surge-protected power strip shunts it out. This trips out the AFCI or GFCI device.

So many have said you have to test your circuits, and sometimes that involves using a megger. Fair enough.

But unless you unplug the surge power strip, using a megger is useless. Using a surge power strip downstream from a AFCI or GFCI device can and will cause nuisance tripping. And testing the wiring without removing such items first is a big waste of time.

My discussion with ELA alludes to this condition, one in which he refuses to acknowledge.

I don't believe that any mini-circuitry contained within that tiny breaker can be sufficient to protect the rest of the circuit from transient surges. Internal circuitry, maybe, but not the whole circuit! Besides, things like GFCI receptacles don't seem to have such features, and surge strips plugged into them also cause nuisance tripping.

Just this week, had another customer complain about nuisance tripping of only ONE of his AFCI breakers. He has several, but guess which one has the computer surge-power strip plugged in? You guessed it, the one that is tripping out. Coincidence? Maybe.

But I'd be willing to bet that removal of that surge strip will solve his nuisance tripping problems.

As stated earlier, I won't waste my or my customers' time troubleshooting until such things have been removed and the condition continues to be a problem. Then and only then it may be time to break out the megger ...

The problem with the career that we have chosen is that unless you have a very expensive recorder that happens to be hooked up to capture the event there is no assurance that we have definitely identified the event that caused the issue.
What we often do is to make a calculated judgment based upon our experience. But, the conclusion that we often come to when it issues such as this one is that there is no way that we can be 100% sure.
It should be considered as a possible cause.

 

[kwired]

In all reality how long did it take you to find it? It's often like trying to find a needle in a haystack, finding something that is so little but causes so much grief.
I'm impressed.

I had a call last summer, older home, quite a bit of lighting on one circuit that had a line to ground fault somewhere in the circuit. Opened a lighting outlet nearest the panel first and thankfully the circuit split three or maybe even four ways from there, unhooked the cable that had the fault and powered the remainder up to see what still did not work. Helped eliminate quite a few outlets but still had maybe three or four lighting outlets that did not work. Ended up finding problem at a ceiling fan. One of those "ceiling hugge" style where the rotor is inside the cover where the supply connections also are. The rotor had been rubbing the ungrounded lead for possisbly years and finally hit conductor. QO breakers trip too fast. GE, Siemens, and some others likely would have taken long enough it would have burned clear, as it was the 18ga fan lead that was damaged. May have needed more than a try or two but at least would allow resetting and then finding the fan doesn't work.

 

[templdl]

I had a call last summer, older home, quite a bit of lighting on one circuit that had a line to ground fault somewhere in the circuit. Opened a lighting outlet nearest the panel first and thankfully the circuit split three or maybe even four ways from there, unhooked the cable that had the fault and powered the remainder up to see what still did not work. Helped eliminate quite a few outlets but still had maybe three or four lighting outlets that did not work. Ended up finding problem at a ceiling fan. One of those "ceiling hugge" style where the rotor is inside the cover where the supply connections also are. The rotor had been rubbing the ungrounded lead for possisbly years and finally hit conductor. QO breakers trip too fast. GE, Siemens, and some others likely would have taken long enough it would have burned clear, as it was the 18ga fan lead that was damaged. May have needed more than a try or two but at least would allow resetting and then finding the fan doesn't work.

Fantastic. It great when a plan comes together.
One thing about the QO is that it has a low mag calibrated instantaneous trip as standard with a high mag as optional.
The Eaton Ch breaker is just the opposite where the standard CH is equivalent to he QO high mag an the low mag CH is optional.
That should explain the difference in that the mag trips are not the same.

 

[tortuga]

You missed my point entirely.

My assertion is that many times nuisance tripping can be caused by transient surges originating from the outside, and then the surge-protected power strip shunts it out. This trips out the AFCI or GFCI device.

Sounds like a fun shop project to test.
What voltage / magnitude do think the transients can be?
How many feet of what guage wire?
I have a coupple of old transformers neon sign 1200V , 600V HID, 480V and some caps they could charge. I would just need a sacrificial surg supresser strip and load. I could run 480V -1000V surge on a afci test circuit and see.

So many have said you have to test your circuits, and sometimes that involves using a megger. Fair enough.

I usually bring a megger and an ideal suretest when going to troubbleshoot these. I have found to many bizarre defective products, wear and tear and even installer errors to list that were only detectable with one of the two.

 

[GMAR519]

AFCI Trips

AFCI Trips

I have heard it attributed to vacuume cleaners and bathroom fans. I was also involved in a project were it was attributed to fluorescent lighting ballasts.

 

[kbsparky]

Sounds like a fun shop project to test.
What voltage / magnitude do think the transients can be?
How many feet of what guage wire?
I have a coupple of old transformers neon sign 1200V , 600V HID, 480V and some caps they could charge. I would just need a sacrificial surg supresser strip and load. I could run 480V -1000V surge on a afci test circuit and see.....

The last one was lightning related. Customer reported that every time a storm came thru, a lightning strike (distant, but evident) would trip out only one of the AFCI breakers -- same one every time. He had a surge power strip plugged into that circuit. :blink:

Told `em to unplug that power strip before the storms arrive, and see if that breaker still trips out from distant strikes.

So far, no more nuisance tripping.... :happyyes: