Circuit Breaker Tripping

My guess is that wire is larger than 12AWG wire and used to run something 240v. Some moved that device (dryer/ A/C / Water heater)… Then took the double (240v) breaker out and put whatever the had laying there. You can measure the size (AWG) of that wire.

But here is why… Inside your panel

WHITE (single wire) should be neutral … the colors I was talking about would be the outside coating of the sets of wire. The last few decades they are also color coated. So 12/2 means 12AWG and 2 wires not counting the ground. So for interior “romex” the color/ ratings

12/2 (yellow) would be black/white and a copper all in the 12awg size/ rated at 20amps
/3 (white) would would have black/red/white and copper all in the 14awg size rated at 15amps and you shouldn’t be seeing any 14/3 wire in you panel.
Orange is 10AWG and 10/3 would be black/red/white and ground you will see and its good for 30AMP,
Black is 8 (40amps) and 6 (55amps)

If you are seeing Red (single wire) inside your panel should be (if romex) 10/3 or heavier. Your red and black have to be opposite phases (L1 and L2) and they have 1 netrual (white). The bus bars (L1/L2) in your panel zig-zag back and forth which make breakers overtop of each other in opposite phases (as long as its not a space saver breaker)
Going down 1 side on the breakers

Lost me at #4/5… “Power” should be “Hot”? which should be a black wire or a red wire. Netrual should be white… Please test with a meter first. Obviously coming from a switch (old way) the Hot would stay in the light fixture and you would run one (white) you your black going to feed the switch and white back to your fixture to have a on/off. (New way) power to the switch box first because of the newer switches needing hot and neutral for the switch.

I would undo everything in that junction box and test with a meter to make sure what is going where and see what AWG the wire is in the box. It sounds like you are saying the red/black/white wire that is going to nothing/the GFCI is defiantly going to that box?

QUOTE" You can run two circuits on a three wire"

not by NEC you cant… Yes, you will have 2 separate circuits that are putting out 120v each but where you are using 3 wire off the panel… . But if you were powering 15 amp on your red and 20amps on your black and they were one the same phase (L1/L1) you would be pulling 35 amps thru the neutral (white) which if its not rated for such can catch fire.

3 wire for 1 (240v) circuit is good. because you are balance (L1-20amp/L2-20amp)and running out of phase that makes it never more than 20amps on your N (white).

Interesting guess, and I believe the washer/dryer were originally in the basement, but the wire is just white romex … not sure if it is 12awg or 14, but definitely not 10awg. For clarity, there are four wires in the romex - bare copper, and red, white, and black insulated copper. So it’s either at 12/3 or a 14/3. Not wired across the phases at the panel - per previous, originally were both red and black were wired directly into a single terminal on the GFCI breaker; now they are twisted together and wired into that same terminal w/a pigtail.

Not sure which part was unclear so let me try again. In the basement is one of those blue boxes (not sure what the right name is - is it junction box?) that has three romex going into it. One of these is the 12/3 (or 14/3) from the GFCI breaker in the panel. I tested this at the blue box and get 120V between black and neutral, and between red and neutral, so both are hot. The other two romex, one is a 14/2 and the other is a 14/3. The red from the 14/3 wasn’t connected to anything. The neutrals of all three were connected together, while the black from the panel was connected to one of the black from one of the other romex, while the red from the panel was connected to the black from the other romex. I disconnected each of these individually (just separated the wires), and when either was separated from the wire from the panel, that circuit was unpowered. The 14/2 goes to the bedroom; the 14/3 goes to the rest of the lights.

I am not sure yet where the disconnected wires in the panel go … all I know right now is that it’s labeled “extra for basement”. So I’m HOPING it does actually go to the basement! :smiley:


FYI here is the pic from the original inspection, 2.5 years ago. Notice how the two wires are wired into the same terminal … a definite no-no! Also notice the breaker above it is not connected to anything.

As it turns out the solution to this bad wiring was no improvement. I will take pix tonight and post for clarity.

In thinking about this more I bet @superman_006 is right and these two were originally for a 240V circuit in the basement. These two breakers are in positions 20 and 22 in the panel. My guess is that they pulled out the heavier wire and replaced it w/the new 12/3. Why they wired it they way they did is beyond me since they had an available breaker right there.

It sounds like splitting the red and black between two breakers in the panel would still be bad … that would be putting up to 30A on the neutral right? So if I want to split the circuit I still need to run another wire to the basement to meet code.

That is 14/3 in you panel going to a AFCI breaker…. NOT a GFCI. Looks like a Siemens or GE box (the same) that used to be something 240 and the 2 breakers would have had a handle tie on it to make a 240v arc fault . Not sure what but it would have been but 1 device like 3500 watts.

And your answer why does it flip…lol because you have a light switch on it with almost 10 amps. If you turn it on slowly you will have an arc inside your switch and that thing will flip because it detects the “arc”. You can set those things off real easy with a drill as well. If the breaker is 15 amp, I would wire nut the red wire on both sides or cut them off as tight to the insulation as I could, Turn that AFCI breaker off, hook it to the 15amp breaker above it. Then when I put in that fancy wet bar I would run a 12/2 wire/ replace the AFCI breaker with a 20amp outlets that run my mini fridge/ blender/ kegerator and retractable stripper pole…

Hey good catch … I see it now. Can’t believe I didn’t notice before. Given the notorious sensitivity of arc faults, I’m thinking it may be the breaker not anything in the circuit. Still need to fix the wiring but maybe I could swap out the breaker for a straight-up GFCI? Or just a plain old breaker?

I wish it was that simple … I probably wasn’t clear enough, the lights aren’t all on the same switch. In fact, they are split between 10 different switched circuits. The most lights on any of the switches in 4. And again, I have not been able to discern any pattern of a particular switch, or group of switches, that trip the breaker. Sometimes nearly all the lights were on when it happened. Last winter it happened multiple times in a row w/just a couple of lights on, and it didn’t matter which ones.

Oh, and as far as I’ve experienced it, it’s not happening when you turn on a switch, but some time after. So you turn on some lights, and then at some point the breaker will just trip. Usually, when it does this, it will keep doing it multiple times in short order.

I just read an article about why AFCI’s trip and it mentioned “lighting controls with LED’s”. Two of the switches are Leviton dimmers that have a small 'finder" LED in them. Could that be it? Note there are not any smart devices in the circuit anywhere.

This would mean putting both circuits that connect to the 14/3 on the black wire; I have been hoping I could separate them out onto two different breakers to reduce the load. Is there a way I can safely do this or am I stuck unless I pull new wire now?

I like the way you think …

The NEC allows it. That’s a multi-wire branch circuit as defined in the NEC. But you’re correct that the two hots can’t be on the same phase or the neutral would pull the combined capacity. But if you connect the two hots to two breakers that are next two each other in the same column, then they’ll be connected to separate phases and the neutral will only carry the capacity of one circuit at a time.

NEC Paragraph 210-4 addresses multiwire branch circuits. (2008)

It is that simple … I’m 100% sure you shouldn’t have any switches on an AFCI circuit. Even a 3watt bulb causes an arc inside the switch on break/ open. The AFCI doesn’t car if your 15amp or .5 amps, it is only sensing for an arc. If you are concerned about actually having an arc in your system… pull every connection you have and visually look at them. If there has been arcing they will be small black marks somewhere

I would stay away from making it 2 circuits out of 1 wire (against code) and even if you get it on L1/L2… someone else may come along and move the breaker or add a space saver putting it back on L1/L1. I would turn that 14/3 wire into 14/2 I’m doubting that you have actually ever tripped the breaker.

None the less 18 cans with ~10w LEDs is 180watts which is 1.5amp and that’s with all 18 on. Also … dimmers!! For math purposes if you are tuning those 18 cans at 25%… that’s 45watts!!! That’s more of lighten the load.

I added a downstairs master to my house 3 years ago and the electrician was required to put an AFCI breaker for all lights and receptacles. Exception was the bathroom on a 20A breaker with GFI in the bathroom.

Yes, I am aware that some of the “local codes” have made it a requirement for “ALL” circuits… most of those cities don’t have any exceptions written including the smoke detector circuit. I’m telling you that they don’t belong in any circuit that has a switch. I can tell you 20 years ago if you put one in anywhere that had a switch you were going to be resetting it a few times a week. I’m sure the electronics inside them are different… But they haven’t changed how the light switch works, therefore… I’m not sure how or that it’s even possible for your “arc-sensing” breaker to say the arc in a light switch is harmless but this other arc where you have a loose connection is not.

I’m sorry, what? The entire reason for this thread is because the breaker has tripped a lot. I’m confused by this statement.

Not likely. The issue is with the huge inrush current for LEDs. But the total wattage for the tiny indicator lights shouldn’t be enough to make any difference even if their inrush current is 10 times normal operations.

You are tripping the AFCI (from an arc) not tripping the breaker (from ampere overages)

Ah, got it. Can you tell the difference? All I know is when I go out there the toggle is flipped on the breaker and the power is off.

No, that particular one doesn’t have anyway to tell you if it’s tripping from an arc or and overload. Do you have another 15amp AFCI breaker in the box that you can switch for that one?

Sadly, no.

Here is my advice - a 15 amp AFCI circuit breaker costs $35 - 45, but it s the easiest thing to try. Sometime the best way to trouble shoot is to start fixing things and see what works. Replacing the breaker is an easy fix. If it works great, if not you have an extra breaker for when one fails. The next step would be to inspect all of the connections in outlets, switches and light fixtures. While you are in each connection point, I would remove the wires from the stab-in connections on the back of the device (if the person doing the wiring used these and given the quality of the wiring job you have described, I assume that they did) and connect the wires via the screw connections. these are much more reliable in the long run. Most of the electricians I know refuse to use the stab-in connections when wiring their own homes. They are alot quicker but much less reliable. that’s just my 2 cents.

1 Like

Not a bad idea, but I’m nervous I may have an actual issue in the circuit somewhere. I think I will just have to bite the bullet and start checking all the connections. Not real happy about it but it seems like it’s the only way I can be certain it’s just a nuisance trip and not a real problem.