Hi, I am in the Philippines and they use a 2 wire (black & white - No Ground)- 220 Volt system. I brought from home (US) some 12-2 wire and want to install 3 outlets for "window type" air conditioner units one that is 720W and the other 2 have not been bought. Neither one will be bigger than this 3/4 HP unit. I need to know what the largest size breaker I can use is. Using e=i*r I figure a 15 amp breaker would do 3300 watts, way more than I need. Could I use a 20 amp or 30 amp Breaker with 12 gauge wire? I can not tell the size of the wire in my electric box except that they are all the same very thick stranded wire. When I ask the question about wire size here all I get is use 15 amp for lights and 20 or 30 amp for outlets. They look at me like I'm from the moon when I ask how that relates to wire size.

The max size breaker for #12 cable is 20 amp.

12 wire is rated for 20 amps-Hope this helps. E=I*R will help you determine how many air conditioners you can put on that 20 amp circuit. Watts divided volts dives you amps.

Cheers