Circuit breaker recently started tripping intermittently

bryank930 · Nov 30, 2016

***Just to note, this is not a constant occurrence. Sometimes everything works fine, sometimes it does not.***

Within the past 2 months or so, when I run my lunchbox planer (14A) and shop vac (11.5A) at the same time, the breaker will trip. So I run in the house to the basement and reset it. With all the lights and everything else still off, I tried to make a cut with my miter saw (15A), as soon as I pulled the trigger, the breaker tripped again. Reset it again, came back outside and made the cut no problem, also ran the planer and vac no problem.

Now, just today, with only the lights (~4A) and computer (5A at 100% load, <1A at idle) on, my table saw (15A) tripped the breaker right when I turned it on. The table saw has never caused a trip before.

All summer long I was able to do any of these along with all of the lights on, and the stereo playing (2.5A) without tripping the breaker. This is the part that really gets me. Why did this just start happening recently? Does temperature affect amp draw that much? :headscrat

I'm pretty sure this has everything to do with my issues, but the entire garage is run off of a single 15A breaker in the house. From what I can tell 12-3 is feeding the garage from the basement panel. The feed from house to garage is 2 black, 1 white, and a ground. One of the black wires has 0v and is capped off on both ends.

I know I have to upgrade the electrical, I just want to know why this started happening. Don't flame me too bad please.

vtsoundman · Nov 30, 2016

Res'd breakers are not designed to trip repeatedly...the continuous severe overloading of running your planer and shop vac at the same time has caused the breaker trip mechanism to become fatigued. You may have also caused some issues with the outlets. If you have any daisy chained backstabbed outlets, you may have caused some other intermittent shorts which only appear when the wires/outlets get hot.

Replace the breaker. :shocking:

If you have truly have 12/3 (two black, 1 white, and 1 ground of number 12).....consider swapping in a 2-pole 20A breaker for a MWB circuit. Usually 12/3 has a black, red, white, green/bare...not black,black,white,green/bare.

Each black can be a hot in the MWB circuit with a single neutral coming back. In the garage, you can branch off two GFCI circuits using GFCI in place of the above.

bryank930 · Nov 30, 2016

I'll check the outlets, there's only 3 out there, 2 on the wall, one for the door opener. I'll double-check the wire colors too. And I'll replace the breaker. The 2-pole 20 breaker sounds interesting.

vtsoundman · Nov 30, 2016

Forgot to mention, the ground is missing from this image...

Also, if you truly have #12 wire, you should be able to swap in a 20A single pole breaker. They likely used whatever was left over (15A)...make sure it isnb't run anywhere else or #14 isn't present in the circuit anywhere either. Before upsizing, make sure you have a #12 all the way.

wyliesdiesels · Nov 30, 2016

If youre planer is truly 14a then youre already close to max and then u have lights computer and vacuum?

And planers draw a lot of juice especially when doing deep cuts. The planer may even spike over 14a on heavy loads or binds.

When motors start there is whats called in-rush current for split seconds. In-rush current can be 4-8x FLA.

Thats too much for a 15a circuit.

Time to upgrade the garage wiring.

The breaker has gotten weak.

What brand of breakers?

bryank930 · Nov 30, 2016

I forgot to mention this is a detached garage that's about 40 feet away from the house.

All of the amperage I listed is whatever the device is rated at in its manual or whatever I could find online.

Sometimes the planer will run for a minute or two before it trips, sometimes it's right when I hit the switch.

The breakers are Square D I think. I'd have to look when I get home to be sure.

vtsoundman · Nov 30, 2016

Detached garage...that means single circuit only unless you put in a subpanel & grounding rod. MWB counts as one circuit....best bet if you have 12/3.

even if you have 14/3, you can use a two pole 15 circuit CB. Do not use a two circuit single pole space saver. If you're out of space, you can use a quad.

250.32 Buildings or Structures Supplied by Feeder(s) or
Branch Circuit(s).

Exception: A grounding electrode shall not be required
where only a single branch circuit supplies the building or
structure and the branch circuit includes an equipment
grounding conductor for grounding the conductive non–
current-carrying parts of equipment. For the purpose of
this section, a multiwire branch circuit shall be considered
as a single branch circuit.

Check out this link...great info there.

http://diy.stackexchange.com/questions/48408/wiring-to-a-detached-garage

rlitman · Nov 30, 2016

vtsoundman said:
Res'd breakers are not designed to trip repeatedly...the continuous severe overloading of running your planer and shop vac at the same time has caused the breaker trip mechanism to become fatigued. You may have also caused some issues with the outlets. If you have any daisy chained backstabbed outlets, you may have caused some other intermittent shorts which only appear when the wires/outlets get hot.

Replace the breaker.

If you have truly have 12/3 (two black, 1 white, and 1 ground of number 12).....consider swapping in a 2-pole 20A breaker for a MWB circuit. Usually 12/3 has a black, red, white, green/bare...not black,black,white,green/bare.

Each black can be a hot in the MWB circuit with a single neutral coming back. In the garage, you can branch off two GFCI circuits using GFCI in place of the above.

Could be the breaker is fatigued. I'm guessing the trip is thermal though, as it isn't instantaneous. Once the breaker is warmed up, it will trip on thermal more quickly the second time.

The MWBC is a great idea. That way, the OP can run one tool off one wire, and the other tool off another. That will keep each pole at a low enough current to not trip the breaker on thermal.

vtsoundman · Nov 30, 2016

bryank930 said:
I'll check the outlets, there's only 3 out there, 2 on the wall, one for the door opener. I'll double-check the wire colors too. And I'll replace the breaker. The 2-pole 20 breaker sounds interesting.

The color code I mentioned is only true with NM / Romex / Sheathed cable...if it is run in conduit, it could very well be black/black/white/green ... and to make things even more confusing, a dedicated ground is not req'd with EMT as the EMT can serve as the grounding conductor. That's great as long as there are no breaks in the conduit.

bryank930 · Nov 30, 2016

I checked the breakers, they are square d brand. The wires I have going out to the garage are black, black, white, orange, and ground. I'll attach a pic when I can get to a pc.

I forgot to mention that there is a switch at the top of the basement stairs that cuts power to the garage (no idea why they did that). Maybe that's why the wires are weird colors?

bryank930 · Nov 30, 2016

Wiring going to the garage

Sent from my VS985 4G using Tapatalk

Radix2 · Nov 30, 2016

And yes, temperature can have a big impact on starting current- the oil in a motors bearings, the stiffness of frozen belts, etc. can really slow down the start up timeand spike up the current for those seconds.

And it gets cold in Wisconsin....

vtsoundman · Nov 30, 2016

bryank930 said:
Wiring going to the garage

Sent from my VS985 4G using Tapatalk

Might need to do some wire tracing...and take a photo a bit futher back so we can see all the wire nuts & junctions. If all these run out to the garage, then might be able to re-purpose these conductors to do a 20A MWBC into the garage.

Can you give us more clues...which wires are is running to the panel? Which ones to the switch? Is there a 3-way switch arrangement out to the garage somewhere? (some of the xtra conductors can be travelers in a multiway switch). Killing power to garage openers is a good anti-theft and likely why there is a switch.

Looks like this is direct burial brought right into the box through the wall? If so, the two blacks are still curious...I'm guessing the panel feed is from the left? Where is the blue headed? Red headed to switch?

Maybe some of the more experienced sparkys can jump in here.

bryank930 · Dec 1, 2016

Here is a wider shot of the box in the basement. Main panel is on the left. The conduit going to the right goes to the lights on the other end of the basement and is NOT affected when the garage breaker trips. I haven't pulled the switch at the top of the stairs yet, so I don't know what color wires go up there, but I DO want to eliminate that at some point.

I know that one of the black wires at the entry point in the garage is dead, 0v. I don't have an easy way to get a pic of that right now, there's a bunch of stuff in the way.

sberry · Dec 1, 2016

The thing that has been saving it is the distance, you should have tripping way ahead of this. The planer is really designed for a 20A circuit. The 15 end on it does not guarantee it wont trip 15. http://www.garagejournal.com/forum/showthread.php?t=272867&page=2 A word of caution as I mention in this pother babble, while this part of the circuit may be 12 its not a done deal the rest of it and hence the reason a 15 was installed on this wire.
All of it needs to be 12,,,, the lights and parts of the light circuits may be tangled here, there is an exception for a light in a travel trailer to be 14 on 20 but not in a structure.
It may or may not be a danger depending on wiring methods but,,,,,,,, just as you have done,,,,,,,,,,,,,, used multiple outlets on a single circuit with the capacity to overload the wire. The 15 may be the correct breaker, it may have a problem and its not a huge expense but I wouldn't hold my breath or would expect it to trip more quickly with a new one.
I didn't follow the story in detail but may have the tool developed a fault too, even minor **** from age makes them lag on start, the planer work fine for a long time and then cause this problem. Fix up the circuit, new 20A breaker, all is well, a month later same deal, cap is taking a shate.

bryank930 · Dec 1, 2016

For real? It's a small table-top planer with a standard 3-prong plug.

sberry · Dec 1, 2016

Sorry I stepped on the commentary a couple posts above about wire size. Correct.
This is a case where the operator is sposed to somewhat know better. I got a bud with a whole machine and wood shop can work from a single circuit, it would be automatic for me to turn one large tool off before turning the other on a single circuit. Same for parasitic load and do you need the stereo wide open while running the planer and the vac?

bryank930 · Dec 1, 2016

No, I just like to keep the stereo on while I'm working, turning it off for a couple minutes while I plane a board sounds like a pain, but if I have to do it, I will. I even tried turning everything off, even the lights while running the planer and vac, and it still tripped. It took a few minutes, but it did. I think that time is because I was taking too deep of a cut.

I'm not really going to dig into all of this until spring. I was just trying to see if there is a way to help out temporarily until I can get the wiring situation figured out permanently.

I'd LOVE to get the garage on it's own service separate from the house like my previous house had, but I have a feeling that's going to cost mega $$.

sberry · Dec 1, 2016

The planer prolly has a 1 piece motor assembly, got a bunch of drive ****, it gets frozen, bearing problems that can add to load, wouldn't rule out a problem with the unit, fine while all brandy new but stuff gets stugg, which is almost stuck, the more stuck the faster the trip.
As was also eluded to my chop saw can easily see way over 30A, I have looked at it a couple times. As high as 40 without too much effort. What feels like a little load to an operator may be double.
About the only things I ever ruined due to thermal have been operator overload, almost nothing automatic ever give me a deal but for a toaster I should have junked. Someone else used it and left the room. Didn't know it had a problem.
A breaker took care of any problem with automatic equipment, legit **** plugged in to proper circuit.

sberry · Dec 1, 2016

I got a bud about pointless and I give up. He probably understands most electrical theory way beyond me but is about in- fricken possible to explain that not only can a 16 wire carry more than 20A its sposed to. he has had faults both at work and at home that should have tripped but didn't cause he has a missing link and some convoluted concept of what a rod does. I am scared to touch anything metal in the place. one giant seething neutral.

sberry · Dec 1, 2016

The good news is he can likely get more than double the power down the same wire for near free. Get 2 20A circuits like kitchen counter tops. Since this is detached and should have disconnect and if was mine would have ground rod to stick a 6 space panel on. I know one just done, runs everything in the place and is ready to heat with a larger wire when the time came and while I am all for thrifty a few bucks spent here provide for local disconnect of all power and wire to the building.
Never got to hook snot to a jbox again. Put a 15 breaker on it, hook old light wire to it and a couple 20's to recept circuits. Would give 1 leg at 20A to a modest tool and a couple lights and the other to a circuit to plug in the heavy motor loads. Even 120V welding or use plug in air comp.

sberry · Dec 1, 2016

rlitman said:
Could be the breaker is fatigued. I'm guessing the trip is thermal though, as it isn't instantaneous. Once the breaker is warmed up, it will trip on thermal more quickly the second time.

The MWBC is a great idea. That way, the OP can run one tool off one wire, and the other tool off another. That will keep each pole at a low enough current to not trip the breaker on thermal.

This is about as good as it gets. They do make a little 2 pole 70A unit like the AC disconnect but this is a good place as an investment, as insurance, for insurance, for safety, for learning and convenience and would definitely consider it a property asset to have a service panel to the structure and as it looks the wire may be legal depends on depth. If it wasn't a panel wouldn't hurt anyway and super simplifies any additional wiring from either side of it (and it can be moved) nut mount it if I could where it could be fed new eventually if a guy expanded.
This type of service is ok for a lot of work, my neighbor who is a master does it this way from a couple basic circuits. The operator adds the loads but for some parasitic light, no headroom for automatic equipment. You can use a microwave and run an electric heater opposite, I added a 3 conductor cable to my place mwbc for kitchen demands, 2 new outlets and didn't use the old anymore.

vtsoundman · Dec 1, 2016

bryank930 said:
Here is a wider shot of the box in the basement. Main panel is on the left. The conduit going to the right goes to the lights on the other end of the basement and is NOT affected when the garage breaker trips. I haven't pulled the switch at the top of the stairs yet, so I don't know what color wires go up there, but I DO want to eliminate that at some point.

I know that one of the black wires at the entry point in the garage is dead, 0v. I don't have an easy way to get a pic of that right now, there's a bunch of stuff in the way.

Both of the black conductors on this end have wire nuts on them connecting them to another wire. If the same black wire was capped at end, then I'd say you have a really easy upgrade here - but looks like you have some detective work to do.

But, I am really encouraged by what I see here....looks like a MWBC with a 2pole handle tie breaker would be a straightforward upgrade (assuming you can't/ don't want to put in a subpanel.)

The MWBC would allow you to balance your loads nicely in the garage. If you find 14 in garage, rewire those circuits and to allow the ckt a proper upgrade to 20A.

Install the MWBC as pic'd above with GFCIs as the first outlets in the chain. You could also opt to installed a GFCI 2 pole in the panel. My preference is for the GFCI outlets as it will give you slightly more headroom for ground leakage current when running power tools. (This is why those portable power taps on construction sites have a bunch of individual GFCI breakers instead of a single GFCI breaker feeding the whole box).

Example :
Ckt A: Vacuum/Lights/radio
Ckt B: Big Loads/planar/table saw

As long as the big loads are divided between the two ckts you should be fine.

bryank930 · Dec 1, 2016

vtsoundman said:
Both of the black conductors on this end have wire nuts on them connecting them to another wire. If the same black wire was capped at end, then I'd say you have a really easy upgrade here - but looks like you have some detective work to do.

But, I am really encouraged by what I see here....looks like a MWBC with a 2pole handle tie breaker would be a straightforward upgrade (assuming you can't/ don't want to put in a subpanel.)

The MWBC would allow you to balance your loads nicely in the garage. If you find 14 in garage, rewire those circuits and to allow the ckt a proper upgrade to 20A.

Install the MWBC as pic'd above with GFCIs as the first outlets in the chain. You could also opt to installed a GFCI 2 pole in the panel. My preference is for the GFCI outlets as it will give you slightly more headroom for ground leakage current when running power tools. (This is why those portable power taps on construction sites have a bunch of individual GFCI breakers instead of a single GFCI breaker feeding the whole box).

Example :
Ckt A: Vacuum/Lights/radio
Ckt B: Big Loads/planar/table saw

As long as the big loads are divided between the two ckts you should be fine.

I'll try to get at the wiring in the garage this weekend and see if I can figure it out, but this sounds optimistic. I was worried that I would have to dump thousands into this.

Now for the MWBC, would I be able to install additional outlets (recall there's only 2 that are really usable now) and split them so the top socket is ckt A and bottom is ckt B? Or would I be better off to do 2 outlets in a 2-gang and have 1 be A and the other B (like 4-5 of those spread around the garage)?

vtsoundman · Dec 1, 2016

Like this?

You have THREE options for MWBC and GFCI...
Version A : 2 x GFCI recept at the beginning of the MWBC that creates two legs.
Version B : GFCI at every outlet
Version C : 2 Pole GFCI Breaker

Version A - Least costly, my preferred method, most flexible.
Version B - Easiest - may be most costly depending on number of outlets.
Version C - Not preferred. May get too many false trips from it aggregating all the ground leakage current from the full MWBC; has an expensive breaker; GFCI reset is furthest from your equipment.

Version A: This One (less costly and easier):

Another Pic of Version A

Another pic of Version A

45976d1329330461-convert-12-3-two-12-2s-split-multiwire.jpg

Version B
Or this One (more GFCIs):

Another way to look at Version B (top)
Version C is the bottom - a 2 Pole 240GFCI

vtsoundman · Dec 1, 2016

bryank930 said:
Now for the MWBC, would I be able to install additional outlets (recall there's only 2 that are really usable now) and split them so the top socket is ckt A and bottom is ckt B? Or would I be better off to do 2 outlets in a 2-gang and have 1 be A and the other B (like 4-5 of those spread around the garage)?

Technically, I think it would be ok to split the outlets with a 2pole GFCI breaker. If you split both sides of the receptacle (Neutral & Hot), then it is not longer a MWBC. However, I am not 100% sure that Code would allow splitting a duplex like this for GFCI applications...I asked this question in another thread...no response yet.

However, if you have the space, don't split the a duplex outlet downstream of the GFCI receptacles. Install dedicated a full duplex outlet for each of the GFCI branches...

You'll be happier with the add'l outlets.

If I were you, I would put a double box (two duplex recept) at each location - one duplex on each GFCI leg. (GFCI leg 1 | GFCI leg 2) That way you have plenty of receptacles and it is easy to move loads around as necessary. You will have to run 2 sets of 12/2 to box as you will now have two neutrals and two hots to deal with (just like it was two circuits).

wyliesdiesels · Dec 1, 2016

sberry said:
The thing that has been saving it is the distance, you should have tripping way ahead of this. The planer is really designed for a 20A circuit. The 15 end on it does not guarantee it wont trip 15. http://www.garagejournal.com/forum/showthread.php?t=272867&page=2 A word of caution as I mention in this pother babble, while this part of the circuit may be 12 its not a done deal the rest of it and hence the reason a 15 was installed on this wire.
All of it needs to be 12,,,, the lights and parts of the light circuits may be tangled here, there is an exception for a light in a travel trailer to be 14 on 20 but not in a structure.
It may or may not be a danger depending on wiring methods but,,,,,,,, just as you have done,,,,,,,,,,,,,, used multiple outlets on a single circuit with the capacity to overload the wire. The 15 may be the correct breaker, it may have a problem and its not a huge expense but I wouldn't hold my breath or would expect it to trip more quickly with a new one.
I didn't follow the story in detail but may have the tool developed a fault too, even minor **** from age makes them lag on start, the planer work fine for a long time and then cause this problem. Fix up the circuit, new 20A breaker, all is well, a month later same deal, cap is taking a shate.

How does distance save it?

Distance is an enemy when it comes to voltage drop.

But a 14a load over 40' is not a problem for #12 or #14.

2012Eli3 · Dec 1, 2016

Would there be a limit on # of receptacles that could follow the GFCI's ?

wyliesdiesels · Dec 1, 2016

2012Eli3 said:
Would there be a limit on # of receptacles that could follow the GFCI's ?

Not in a residential environment

vtsoundman · Dec 1, 2016

wyliesdiesels said:
How does distance save it?

Distance is an enemy when it comes to voltage drop.

But a 14a load over 40' is not a problem for #12 or #14.

You're right 14A is not biggie...but if the motor does not have a cap/soft start in it, there will be will decent inrush current as the motor comes up to the speed.

WRTO "distance saving it..."

Depends...A stiff source would allow a large current slug to be drawn, but it would be shorter in duration (higher peak current, fewer cycles as the motor spins up).

However, a softer source would suppress the peak but stretch it out over more cycles. (lower peak current, but over more cycles as the motor spins up).

So - pick you poison...the I2T curves of the breaker is stressed in either case and it becomes a race condition.

With the OP running both a planer, a vacuum, and other stuff at the same time, he likely started to heat up the thermal trip...and its ability to withstand high surges dropped with time.

The more he did this, the more the little bimetal strip/spring arrangement (assuming a thermal breaker) becomes fatigued.

UL does not perform repeated breaker clearing operations during breaker testing/Listing.

Expecting a res'd breaker to perform properly after repeated fault clearing activities is asking for trouble - the stiffer the source, the higher the avail fault current, the more the breaker contacts become fatigued.

For Good Breakers: The curve below will shift to the LEFT and down as a breaker becomes 'weak' & fatigued, but you can't be assured of this behavior. The curve below is for a 20A SqD QO Breaker...

For some really crappy breakers (ZINSCO, FPE) ...it would shift to the RIGHT and UP!!! Yikes!

My in-house UL compliance engineer would often say: that curve is only guaranteed for 1 clearing event -- he had be running a UL certification lab for many many years. (As a design engineer, not sure I subscribe to that statement...but I do agree with his sentiment...Depending on the severity of the event and the amount of available fault current and inductance in the line, I might say a res'd breaker is good for a few events before it needs to be replaced).

Just for kicks...if folks wonder why it is possible to have 8-20x rated current and not have the wire turn into a fuse -> the wire itself also has a I2T curve. A wire is nothing more than a fuse that never clears.

Here is a graphic to help:

sberry · Dec 1, 2016

This is a 15 on a 12 wire for 50 ft or so, not really going to suffer drop or overheat, prolly won't trip 20. We worry constant about a couple V drop but large wired often speed up trips especially close to panel with good service.

sberry · Dec 1, 2016

I am going to look at that in morn.

bryank930 · Apr 24, 2017

Sorry for dragging this up from the dead, but I'm FINALLY getting ready to start this project.

I have a question about what breaker I should use for the MWBC. I'm pretty sure I have a QO panel, and I'm having a hell of a time trying to find 20A 2-pole handle-tie breakers for it.

Will the breaker in the link do the same thing, or will both "circuits" in the MWBC split the 20A allowance, leaving me pretty much in the same circumstance I'm in now?

http://www.homedepot.com/p/Square-D-QO-20-Amp-2-Pole-Circuit-Breaker-QO220CP/100032386

Am I correct in assuming that a handle-tie breaker acts like 2 separate breakers with their handles tied together?

EDIT:

Just found this: https://www.amazon.com/dp/B000WUNT2O/?tag=atomicindus08-20

Will that work?

wyliesdiesels · Apr 25, 2017

vtsoundman said:
You're right 14A is not biggie...but if the motor does not have a cap/soft start in it, there will be will decent inrush current as the motor comes up to the speed.

WRTO "distance saving it..."

Depends...A stiff source would allow a large current slug to be drawn, but it would be shorter in duration (higher peak current, fewer cycles as the motor spins up).

However, a softer source would suppress the peak but stretch it out over more cycles. (lower peak current, but over more cycles as the motor spins up).

So - pick you poison...the I2T curves of the breaker is stressed in either case and it becomes a race condition.

With the OP running both a planer, a vacuum, and other stuff at the same time, he likely started to heat up the thermal trip...and its ability to withstand high surges dropped with time.

The more he did this, the more the little bimetal strip/spring arrangement (assuming a thermal breaker) becomes fatigued.

UL does not perform repeated breaker clearing operations during breaker testing/Listing.

Expecting a res'd breaker to perform properly after repeated fault clearing activities is asking for trouble - the stiffer the source, the higher the avail fault current, the more the breaker contacts become fatigued.

For Good Breakers: The curve below will shift to the LEFT and down as a breaker becomes 'weak' & fatigued, but you can't be assured of this behavior. The curve below is for a 20A SqD QO Breaker...

For some really crappy breakers (ZINSCO, FPE) ...it would shift to the RIGHT and UP!!! Yikes!

My in-house UL compliance engineer would often say: that curve is only guaranteed for 1 clearing event -- he had be running a UL certification lab for many many years. (As a design engineer, not sure I subscribe to that statement...but I do agree with his sentiment...Depending on the severity of the event and the amount of available fault current and inductance in the line, I might say a res'd breaker is good for a few events before it needs to be replaced).

Just for kicks...if folks wonder why it is possible to have 8-20x rated current and not have the wire turn into a fuse -> the wire itself also has a I2T curve. A wire is nothing more than a fuse that never clears.

Here is a graphic to help:

Well thx for the engineering education. And no im not being sarcastic. Gonna take me a little while to digest this so Im gonna book mark it.

bryank930 said:
Sorry for dragging this up from the dead, but I'm FINALLY getting ready to start this project.

I have a question about what breaker I should use for the MWBC. I'm pretty sure I have a QO panel, and I'm having a hell of a time trying to find 20A 2-pole handle-tie breakers for it.

Will the breaker in the link do the same thing, or will both "circuits" in the MWBC split the 20A allowance, leaving me pretty much in the same circumstance I'm in now?

http://www.homedepot.com/p/Square-D-QO-20-Amp-2-Pole-Circuit-Breaker-QO220CP/100032386

Am I correct in assuming that a handle-tie breaker acts like 2 separate breakers with their handles tied together?

EDIT:

Just found this: https://www.amazon.com/dp/B000WUNT2O/?tag=atomicindus08-20

Will that work?

If you have a Q0 panel then you need to use Q0 breakers.

The breaker in either link will work the second being a classified breaker for use in Q0 panels.

I would use the Q0 breaker.

As far as that breaker goes, it is a common trip breaker meaning if one side trips, the other side will trip as well.

Sq D makes their common trip breakers a little different than other manu. as they put only one handle on them.

No, there being only one handle does not mean you will have only 20a. It is a 2 pole 120/240v breaker so you have 2 poles @ 20a.

The whole reason for the handle tie requirement on MWBCs is so that all ungrounded conductors are disconnected at the same time so that the circuit can be safely worked on.

Without the code, one could use 2 single pole breakers located in non adjacent spaces and shut off only one breaker to work on the circuit. Person then disconnects neutral @ some place in the circuit and gets shocked because the other hot leg is still energized.

Circuit breaker recently started tripping intermittently

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