Hoping someone can aid in the diagnostics..
Last year I added an addition to my home along with a 100A sub-panel to power it. Everything has been working fine until recently when one of the new AFCI breakers tripped. Went to the panel and reset it it. Came home the next day to find it tripped again (same circuit). This is a 15A living room circuit that is in no way overloaded.
First thing I did was inspect the appliances on the circuit. Visually, everything looked fine so I swapped breakers with another 15A AFCI. Within two days the same circuit tripped again (i.e. the problem stayed with the circuit).
Next I removed all of the devices (plugs & switches), checked the tightness of the screws and made sure the bare ground wire was not near the neutral & hot wires in the various boxes. Circuit tripped about a week later.
Coincidentally, the circuit seems to trip more often than not when turning on a particulat table lamp so we tossed out the table lamp and I replaced the corespending receptacle. Circuit tripped within a few hours…
Here is what is on the circuit:
8 plug receptables (one of which I replaced as noted above)
2 recessed cans (switched)
hard wired smoke detectors
3 switches
1 incandesent ceiling light
Below are the items pluged into the receptables:
3 table lamps (2 were replaced)
1 radio
1 TV
1 cable box
For what it’s worth, the tv, cable box and radio go though a surge supressor.
At one point, I thought the recessed cans were heating up and the moving around causing the bizzare fault so I turned their switch to the off position. Breaker trips with the cans turned off.
At one point, I thought the radio was causing the issue so I unplugged it for a few days. Breaker trips with the radio unplugged.
Sorry for the long post. I think I have eliminated several items but not sure what to try next. Any thoughts?
Replies
Have you noticed if it trips when either the TV or cable box is powered on? Or if it trips when something is plugged in? The power supply for my laptop causes an AFCI breaker trip about 50% of the times that it's plugge in.
just a thought ........
and I'm still surprised with these AFCI situations since my first experience quite some time ago-ceiling fan would trip it (in room afci control-not a breaker).
Do you have anything like a timer, cell phone charger, battery charger or something like it........................on the circuit?
Have you changed the battery backup in your smoke detectors?
No timers or chargers plugged into the circuit. I HAVE NOT changed the batteries in the smokes and it's been a year since installation. That somehow makes sense although I would think the smokes would chirp vs tripping the breaker. Certainly worth a try since it appears I am overdue to change out the batteries...
I just thought I'd ask the questions, as you did trying to ....
figure this mystery out. Hoping there'd be something of worth in it.
If this pans out, you've just given another reason in the afci "WHY". Who knows, it's evidently a safety measure from the powers that be................maybe it's just another friendly reminder like turning the clocks back, to check the smoke alarms.
Best of luck.
edit: don't forget, the smokes are linked (probably) check/change the batts in 'em all.
Well, it might be, but with only a year on 'em-I'm doubting.
Here when we have an outage-we do get the same chirp from the close smokes, not sure about the others in the house as I'm usually at the desk when I hear them.
I mentioned the ceiling fan as a culprit when these afci's (localized-not breaker) came out because that was deemed to be the fault-something about a motor.
Speaking of which-you didn't put a sump in the addition and that could be going on causing the spike and outage?
Thanks Calvin, there is no sump & no fan on the circuit but I an going to double check and make sure nobody has plugged in anything else while I was not lookiing :)
I am kiinda suspicious of the surge protector that the tv and cable box are plugged into (guess I am suspicious of everything on this circuit). Have they been known to cause issues?
I am trying the batteries in the smokes first. If the breaker still trips with new batteries, I will remove the surge protector for the circuit and give that a try.
For me, other than that early trip several yrs ago............
I've not been around new residential construction enough to offer any opinion. And here in our corner of Ohio, remodels haven't seen the full impact of them, tho I expect that to change.
Please find the cause and post it here. Those here with electrical experience have given you some methods to trace wiring and device problems. If you did the wiring you should remember the paths your wires took. If you took some shots b/4 covering up, that might help you in tracing.
I know just enough to tell me when to call an electrician I trust. Just a dumb carpenter.
A surge protector can cause problems, either because it has large capacitors between the power wires and ground, or because the MOV device in the unit is sensing minor voltage spikes.
Time to start splitting the circuit apart. Figure out how all the wires are daisy-chained and disconnect the tail-end half of the circuit in one of the boxes. If you need stuff on that circuit, temporarily wire it to an extension cord plugged into a different circuit. (If you play your cards right you can plug the extension into an AFCI circuit and be testing both halves at the same time.)
Eventually you'll narrow things down to one or two outlets/fixtures.
One thing to remember is that an AFCI or GFCI will trip if the neutral and ground contact each other, or if the neutral from one circuit contacts the neutral of a different circuit. Anywhere where you might have two circuits in the same box is a point of particular suspicion.
http://www.thecircuitdetective.com/afci_circuit_breakers.htm
Maybe this will help. Interesting note on the site about AFCI doing both Arc Fault and Ground Fault detection which makes the list of possible causes that much longer.
Tripping when an incandescent lamp is turned on makes little sense. An incandescent lamp would not be expected to produce any sort of surge when being turned on, and only the tiniest when being turned off. If there was a short from hot to the case of the lamp then that could do it, of course, but it would be relatively consistent, and wouldn't likely cause trips in the middle of the night.
I agree, no sense at all but I figured I would mention it. Both this lamp and the one we tossed out are the type that hold a 3 way bulb (30, 70, 100 watt).
BTY, no breaker trips today.
What brand of panel and breakers are you using?
I think my panel is about 3 yo now and I've only tripped when a lamp blew out.
The sub-panel for the addition is a Siemens 100A.
Update
These hardwired interconnected smokes have battery back-up. Around 2 weeks ago, I replace dall of the batteries and the breaker has not tripped since. Not entirely sure if this is it, only time will tell. Also not sure why a marginal battery would cause the AFCI to trip (not even sure if the batteries were marginal but there were ~1 year old)...
It seems unlikely the batteries would have anything to do with it. However, if the units are interconnected with a 3rd wire, and someone wired units on different circuits on the same shared wire, that could serve to trip them, and it's vaguely possible that, in an attempt to do a low-battery "chirp", one of the units could trip the breaker.
(If this is indeed the case, the units should not be interconnected this way. An actual alarm would cause the breaker to trip and possibly cause some units to not sound (including the one that's detecting the smoke).)
This system does have the 3rd wire for interconnect and I am certain that the 3rd wire is not connected to anyother circuit. The smokes function fine via the smoke test (fire department tested each unit for certificate of occupancy). The breaker does not trip when there is a real alarm.
It's only been two weeks without a breaker trip so I'm not even sure the batteries are the culprit. Maybe I should stick a deam battery in and see if the breaker trips???
I would start with the TV and cable box kludge.
Try running the whole thing on an extension cord from another circuit. I have a daewoo TV that will trip a GFCI if it is connected to anything that is grounded.
Any relation to the weather?
I branched off a GFI from a bathroom once, using conduit... and would trip the GCFI occasionally when it rained. No water exposure, i suspect it just got a little humidity condensation inside the tube.
Any luck? I'm curious if you ever figured this one out.
I have been fighting this one for a while (yes it has been tripping about 1X per week). Went back and looked it all the things of interest. It seems that the majority of times that the beaker trips is when we are turning on a table lamp. The odd thing is that the lamp was replaced half way through this mess. Of interest is that both lamps (the one that went to the landfill and the present one) are of the type that take a 3 way bulb. Well 2 weeks ago, I noticed that the bulb in the lamp is not a 3 way bulb but actually just a regular 60W (no 3 way bulb). As it turn out, we have been running all of our 3 way lamps with 1 way bulbs. Two weeks ago, we installed 3 way bulbs in the 3 way lamps. No trips in 2 weeks. Too early to tell but maybe??
If this is the problem, how does a wrong bulb trip an AFCI?
A poorly designed 3-way socket could short out when a 1-way bulb is installed. It's not supposed to happen, of course, but with the carp they make these days you never can tell.
In addition, table lamp switches (even the good ones) are fairly crummy, and could arc sufficiently to trips an AFCI, I suppose.
Did you check out the wiring in the ceiling light?
If this is the typical ceiling box that is a catch all J box look at that big cludge white wirenut. Make sure there is no bare wire showing
>>>As it turn out, we have
>>>As it turn out, we have been running all of our 3 way lamps with 1 way bulbs.
This raises a red flag for me.
Three way bulb fixtures (at least when I grew up) consisted of an el-cheapo rotating contact mechanism that could easily create a minor electrical arc with each turn of the switch. AFCI breakers are designed to detect such arcs.
Could this be the culprit?
Scott,
I do not think the el-cheapo rotating mechanisms have gotten any better but even a good quality on/off switch produces an arc. I thought the AFCI breakers were supposed to distinguish between a real arc fault and the type of arc produced from swiching.
I do agree, the 3 way switches found in these lamps are especially el-cheapo and the arc could be much more than the arc produces by the typical wall on/off switch. So, maybe/hopefully this is the problem. I was hoping someone would come along and say. You dummy, everyone knows you cannot put a 1 way bulb in a 3 way lamp because it causes arc fault breakers to trip... At this point only time will tell.
One thing is that with the 1-way bulb in the 3-way socket you get a pattern of arcs as you have to double-switch through the detents. (You'd get the pattern with a 3-way bulb too, but probably not as pronounced.) In addition, with such a switch you're far more likely to "overshoot" and have to go around again.
**Update**
Well, no AFCI breaker trips since early July. Consider the frequency was around 1 trip per week, I think the problem is solved. As mentioned earlier, we were running regular (1 way) incandecent bulbs in 3 Way lamps. Installing 3 way bulbs did the trick....
Conclusion: AFCI circuits...don't run 1 way bulbs in a 3 way socket/lamp.... Sounds so simple but had me stumped for a while.
dt
Take a look at this response to an older thread on afci.
Then peruse the rest of it.
A little more background to add to your thoughts.
http://forums.finehomebuilding.com/breaktime/general-discussion/arc-fault-breakers-every-circuit#comment-2213331
If your house is anything like ours, whenever a one way bulb was in a 3 way switch, we would wouldn't click..........click.........click it was ClickClickClick almost instantly. I wonder if thats how they were used in your house and if that would have anything to do with it.
Try a GFCI breaker in that circuit, see if that trips. That will divide the problem in half. If it still trips it eliminates the idea that this is an arc and gets you looking for a ground fault.
I had one that kept tripping. It got to the point that I couldn't even get it to click back and stay in the "on" position. It was only two months old. My electricain friend says they can be touchy and sometimes you just get an extra trippy one. I replaced it and have not had any trouble since.