What I found at the sub panel in the garage was an old Murray 120/240 being fed from the main with a 12/2 or 10/2 (dont remember) bx. At each phase I get 120 from phase to neutral. It has 2 double pole 15 amp breakers, which they used for 4 circuits. One for a swimming pool filter (8 amp) ,and a few light fixtures (keeping in mind that the filter is on a timer so it's not constant). Second side of the two pole is feeding a refrigerator, but the other breaker has two other separate circuits. One serving a GFCI, and two outlets. The final pole is feeding two other outlets.
What concerns me is that they went with three circuits into a junction, and in that junction all the neutrals are together (one being for a GFCI). Shouldn't the circuit feeding the GFCI's neutral be separated, as if to be a dedicated circuit? In the subpanel they are all in individual on the neutral bar.
Another thing is that they had to jump the phases to get the other half of the panel to work. I just never seen a circuit wired that way, or the phases jumped.