circuit breaker
 

Just a question, what is the purpose of linking/attaching 2 x 15 amp breakers together? (They are single 15 amps but joint with a cap on the top)

Thanks

This configuration would be for a 240 volt circuit.

ok so its 240 volts @ 30amps or 15 amps?

What would you plug into it?

I know a dryer is 240v@30amps
Baseboard heater can't remember?

Circuit amperages are never combined. This is a 15A 240v, or 120/240v, circuit.

Could be an AC, a motor load, electric heat, etc.

if electric heating what is the minimum wire size?

A 15A circuit can be wired with #14. This is the smallest building wire size.

Could be a multi wire branch circuit. Two circuits sharing a neutral wire.