Here are some diagrams which might be helpful -- snapshots of a circuit simulation. I don't have reputation to comment, but wanted to reply to the method of finding 'actual electricity being consumed' -- I don't think averaging the lines is effective, as also illustrated by these diagrams. Unless I've made a mistake, of course.
Both circuits have 24A total load. The only difference is the balancing of the 120V circuits (as a side-experiment). The sum of the legs is 36A, and the average of the legs are 18A.
Perhaps one way to measure the total load of a 120/240 system with a clamp meter, would be thus:
- flip breakers in order to test only 240V load: L1 = L2 so either leg will show total load.
- then test 120V only, adding L1 + L2.
- total load = 120V L1 + 120V L2 + 240V L1.
Or get the 120V number by subtracting 240V load from total load, and doing the math with neutral. Be careful not to confuse Multiwire Branch Circuit pairs with 240V circuits, or it will mess up your results. MWBC also uses red/black, and sometimes 2-pole breakers.
Also note that the neutral current is the difference of 120 L1 and 120 L2.
