# Strange Circuit Breaker Behavior **URL:** \ **Category:** Factual Questions\ **Created:** [June 8, 2021, 7:25pm UTC](https://boards.straightdope.com/t/strange-circuit-breaker-behavior/943862 "2021-06-08T19:25:05Z")\ **Posts on this page:** 10\ **Page:** 2
**Author:** ![Melbourne](https://avatars.discourse-cdn.com/v4/letter/m/b5e925/32.png) [@Melbourne](https://boards.straightdope.com/u/Melbourne)\ **Post date:** [June 10, 2021, 2:07am UTC](https://boards.straightdope.com/t/strange-circuit-breaker-behavior/943862/21 "2021-06-10T02:07:34Z")
> [@Marvin\_the\_Martian](#): > > I can imagine that something that has a worn relay or electromechanical switch cold have enough internal arcing when the switch/relay opens to cause the AFCI to trip. For example, light switches. ---
**Author:** ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)\ **Post date:** [June 10, 2021, 2:26am UTC](https://boards.straightdope.com/t/strange-circuit-breaker-behavior/943862/22 "2021-06-10T02:26:45Z")
> [@OldOlds](#): > > It’s our preferred TV spot, so I will let you all know what (if anything) happens. For me, holding a switch too long (you hear it arcing ) has tripped the ACFI. This happens more when there is a reactive load like a motor or LED or fluorescent light. The speed control on the ceiling fan (when you slide the slider real real slow to make it arc) can also do it. Treadmills are another culprit. ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [June 10, 2021, 7:16pm UTC](https://boards.straightdope.com/t/strange-circuit-breaker-behavior/943862/23 "2021-06-10T19:16:10Z")
Longshot: Is condensatiin a possibility? If it’s happening as the air gets colder, could water i trusion be tripping the breaker? The other thought is automatic lighting that might be trying to go on at that time, like outdoor patio or house lights on a photocell. ---
**Author:** ![kayaker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kayaker/32/441_2.png) [@kayaker](https://boards.straightdope.com/u/kayaker)\ **Post date:** [June 10, 2021, 10:31pm UTC](https://boards.straightdope.com/t/strange-circuit-breaker-behavior/943862/24 "2021-06-10T22:31:08Z")
> [@Sam\_Stone](#): > > Longshot: Is condensatiin a possibility? If it’s happening as the air gets colder, could water i trusion be tripping the breaker? Post given the Makes Sense award. ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [June 12, 2021, 3:33am UTC](https://boards.straightdope.com/t/strange-circuit-breaker-behavior/943862/25 "2021-06-12T03:33:01Z")
> [@ArtBeforeScience](#): > > … Once, the refrigerator breaker tripped… and there’s nothing else on that circuit. Appliances with a hefty motor (like refrigerators & freezers) often trip GFCI/AFCI’s when they start. So they should NOT be put on such a breaker, just a regular breaker (and should be on a separate, dedicated circuit). But young, inexperienced electricians (or architects lacking knowledge) often put GFCI or AFCI breakers for every circuit – they think they’re “being safer”. But they aren’t, because the frequent nuisance trips lead to the homeowner eventually replacing the breaker. (like Crafter\_man mentioned). that’s fine on a dedicated refrigerator circuit. But then the homeowner decides that’s the proper fix for other circuits, which DO need the GFCI/AFCI protection. ---
**Author:** ![OldOlds](https://avatars.discourse-cdn.com/v4/letter/o/a3d4f5/32.png) [@OldOlds](https://boards.straightdope.com/u/OldOlds)\ **Post date:** [June 12, 2021, 11:56am UTC](https://boards.straightdope.com/t/strange-circuit-breaker-behavior/943862/26 "2021-06-12T11:56:03Z")
Well, I figure I owe y’all an update. After coming here and bothering you with my tale of mystery, no further issues. In looking at the devices plugged into the circuit I did unplug a couple and plug them back in, but otherwise changed nothing. That said, I had not realized that AFIs were so finicky, so I did learn something. Someday I’ll tell you the story of the time I was replacing a light fixture and I tripped the GFI outlet that was in-line with it, except I didn’t even know it was there. That had me baffled for a while… ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [June 14, 2021, 3:10pm UTC](https://boards.straightdope.com/t/strange-circuit-breaker-behavior/943862/27 "2021-06-14T15:10:21Z")
I thought Square-D was very, very good. ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [June 17, 2021, 7:17am UTC](https://boards.straightdope.com/t/strange-circuit-breaker-behavior/943862/28 "2021-06-17T07:17:53Z")
Square D has a home/DIY grade of products (“HomeLine”) and higher quality, commercial/industrial grade. But AFAIK both grades are considered pretty good products. ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [June 24, 2021, 6:25pm UTC](https://boards.straightdope.com/t/strange-circuit-breaker-behavior/943862/29 "2021-06-24T18:25:14Z")
For the OP - are the breakers AFCI or CAFCI? (Combination arc-fault and ground-fault) and what brand? Someone mentioned Square D - their AFCI breakers usually have a blue test button, and their CAFCI breakers have white test buttons. Square D makes good stuff. Good enough that other folks will try to make counterfeit copies. There have also been recalls here and there. Think the most recent for their AFCI breakers was over ten years ago. AFCI breakers are notorious for nuisance trips, but as @Crafter_Man noted, there may be a real reason. Nicked wire insulation is definitely one of the top causes, so an apartment where there were nails and screws in the conduits along with the wires, I would expect plenty of trips. GFCIs don’t like having other GFCIs downstream, so that might be a possibility. Testing this would involve disconnecting the wires going to the outside outlet. ---
**Author:** ![Jasmine](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jasmine/32/2964_2.png) [@Jasmine](https://boards.straightdope.com/u/Jasmine)\ **Post date:** [June 24, 2021, 6:29pm UTC](https://boards.straightdope.com/t/strange-circuit-breaker-behavior/943862/30 "2021-06-24T18:29:18Z")
I really believe you need to get a professional out there. If you fo have a wiring, you don’t want to find out the hard way. [Previous page](https://boards.straightdope.com/t/strange-circuit-breaker-behavior/943862.md?page=1)