House Wiring in USA question.

Looking at my breaker box how do I find which 120vac circuits are on one 240vac leg and which are on the other 240ac leg?

Depends on the panel. In short without having in depth knowledge or opening the panel you won’t know by looking.

On most newer panels the breakers will alternate down down each side. Without looking at the buss bar however you wouldn’t be able to tell how they correlate left to right.

Some panels are like this

+|-

  • |+
    +|-
  • |+

Others are like this

+ +
+ +
- -

There are also panels out there that don’t alternate on all breakers so a 2 pole breaker can only be used in the top or bottom slots or even more frustrating only the middle two breakers because the buss bars are top and bottom.

btw you most likely have 2 120v legs. You wouldn’t have a 240 leg in your panel. To get 240 the circuit uses both 120 legs

Right, I meant 120vac leg since 240 will have 2 wires with neutral being used for the legs to make the 120 sides.

I will have to take a look at the panel again as it should be obvious since I will have neutral and 2 legs with 1 leg going to one set and another go to the other set (wishful thinking it will be this easy to spot).

You would think they would keep it simple and left side one leg right side the other, lol. I know I know too simplistic, hehehe.

by alternating the leg on a side then it makes it easy and compact to have a dual breaker.