Replacing quadplex breaker with 2 double-pole breakers?

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mwalsh

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I have a quadplex breaker in my service panel (for the stove and A/C) that I'm pretty sure has a weak leg - it trips about every sixth time we turn the A/C on, and always at the same leg. I think they went with a quadplex because there wasn't a whole lot of extra space in the old 125A panel. Well, now we have the super deluxe 200A panel, with a ton of extra room in it, and so I'm thinking of ditching the quadplex and going with 2 double-pole breakers instead. Does anyone have a compelling reason why I shouldn't? The reason I don't really want to buy a new quadplex is that I already have a few extra double-pole breakers, and I'm sure two of them will turn out to be the sizes I need.

Then, obviously, if the A/C continues to trip the same size breaker, we'll have omitted it as being the source of the problem, and will call in a HVAC guy and/or electrician.

Edit: It occurs to me that I could also swap the wiring from leg to leg on the same breaker, and see if the trip moves with it.
 
smkettner said:
The poles should trip together... does it have the bracket that goes across to turn both off?
Otherwise 2 pole or 4 pole is fine.

It has a thin metal bracket (see picture). Now it's entirely probable that internally both sides of the breaker have tripped (I think that's what's supposed to happen), but only the switch on the one leg "looks" tripped (and it makes that metal bracket twist when it does):

Edit: Actually it's exactly the same breaker as pictured, and is marked "no common trip", which leads me to think that the one side could trip by itself.
 

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mwalsh said:
smkettner said:
The poles should trip together... does it have the bracket that goes across to turn both off?
Otherwise 2 pole or 4 pole is fine.

It has a thin metal bracket (see picture). Now it's entirely probable that internally both sides of the breaker have tripped (I think that's what's supposed to happen), but only the switch on the one leg "looks" tripped (and it makes that metal bracket twist when it does):

Edit: Actually it's exactly the same breaker as pictured, and is marked "no common trip", which leads me to think that the one side could trip by itself.

I would not use these types of breakers for charging circuits. You hit it on the head when you zero'd in on the "no common trip" aspect of this breaker. You definitely want both poles to open on a fault or an overload, so you need a "common trip" breaker. Just because the handles are tied together with a metal strap does not mean that all poles open; on the contrary, only one 120 volt leg will open leaving the other side hot on a line to ground fault.
 
there are some panels or places in panels where you can't even install that type of breaker. The bus bar has a bit of extra meat in the right spot so it blocks it from fully being inserted. Generally, you should always try to stay away from using those "peanut" circuit breakers. Also, I have seen quad breakers that were rated for common trip.
 
Just to update...

Instead of messing with replacing breakers, I decided to swap the wiring around on the existing breaker, to see if my supposition that if a) something was wrong with the A/C unit, the trip would follow the wiring move or b) a weak breaker would mean the trip would remain on the same leg.

Well, imagine my surprise to find that the breaker no longer trips at all. Or at least it hasn't so far, and it's been almost a week now, with me turning the A/C on at least twice a day.

This is a little above my pay-grade, but is it possible that the load from the A/C unit is so unbalanced that it is enough to trip a weak breaker but is fine on a healthy breaker? And that, conversely, the load on the other leg is not enough to even trip the supposed weak breaker? 'Cause that's sort of where I'm at with my guessing.
 
Most likely your ac uses a 120 volt fan, and it's connected to the leg that always trips. You should never run peanut breakers unless you have to, especially ones marked "no common trip". Honestly if I was putting in a new service panel, I'd buy all new breakers. Throw the old breakers out with the old panel. Now that you have it all together I'd leave it, but I'd take out that quad breaker and replace it with 2 NEW double pole breakers.
 
johnrhansen said:
Most likely your ac uses a 120 volt fan, and it's connected to the leg that always trips. You should never run peanut breakers unless you have to, especially ones marked "no common trip". Honestly if I was putting in a new service panel, I'd buy all new breakers. Throw the old breakers out with the old panel. Now that you have it all together I'd leave it, but I'd take out that quad breaker and replace it with 2 NEW double pole breakers.

I didn't know what you meant by "peanut breakers" so I googled it and found a discussion of them where they were also called

twin breakers
tandem breakers
Half-size
Half-inch
Twinkies
piggy backs
Thin Mints

anyway whatever you call them the opinions on them are mixed as well.
 
I just googled it too. this was my favorite comment:


I use them, but only on lightly loaded circuits, I figure you will wind up with excess heat in the breaker pretty easy with a tandem that has two fully loaded circuits on it...

Very true. Breakers do get quite warm, and one of the most heavily loaded circuits I can think of is an electric car charger. Full current for an hour or more really can make flaws in the circuit turn to smoke and sparks...
 
mwalsh said:
Just to update...

Instead of messing with replacing breakers, I decided to swap the wiring around on the existing breaker, to see if my supposition that if a) something was wrong with the A/C unit, the trip would follow the wiring move or b) a weak breaker would mean the trip would remain on the same leg.

Well, imagine my surprise to find that the breaker no longer trips at all. Or at least it hasn't so far, and it's been almost a week now, with me turning the A/C on at least twice a day.

This is a little above my pay-grade, but is it possible that the load from the A/C unit is so unbalanced that it is enough to trip a weak breaker but is fine on a healthy breaker? And that, conversely, the load on the other leg is not enough to even trip the supposed weak breaker? 'Cause that's sort of where I'm at with my guessing.
It is possible you had a loose connection, higher resistance would create heat and pop the breaker. You could try swapping the wires back, to see if the problem returns.
 
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