Two pole 220-volt breakers are used for large equipment such as air conditioners, ovens, heat strips, steam units and electric dryers. Two pole breakers take up two adjacent spaces in the electrical panel box. Any breaker can wear out over long periods of time. Sometimes a breaker can become weak and trip uncommonly often, or will no longer reset; in both cases the breaker should be replaced. Replacing a 220-volt breaker is fairly simple. The main concern should be making sure that the replacement breaker is acceptable for the panel box according to the list of allowable breakers printed inside of the breaker panel.
Turn off the main house breaker. The only wires that will be energized will be the wires going into the main breaker. The buses in the panel and all of the other breakers and wires will be powered off.
Remove the dead front covering the breakers from the electrical panel by removing the screws at the bottom of the cover and pulling it out from the bottom then down out of the holding tabs at the top. Using your straight tipped screwdriver, loosen the two screws that hold the hot wires into the breakers connectors. Pull the two wires completely out of the breaker.
Pull the 2-pole breaker off of the panels buses; there are tabs in the metal rail that hold the side of the breaker with the connections onto a rail. When removing the breaker you can pull on the switch itself towards the connection screws rocking the breaker on the rail. Once the breaker is off the buses, you can slide it out of the rail.
Install a replacement breaker of the same brand, type and amperage of the original. Hook the screw connection side of the breaker into the rail and push the other side into the buses. The breaker will line up with all of the others when installed properly.
Connect the two hot wires to the new breakers screw connections. It doesn't matter which wire goes to which screw on the breaker, they are both 110-volt legs and together they make 220 volts. If the wire is aluminum, apply some anti-oxidation compound, no-lox, to the wires before you put them under the connection screws. Tighten the screws down well.
Replace the dead front cover over the breakers pushing the cover into the holding tabs at the top and then screwing in the screws at the bottom to hold it in place. Turn the main breaker back on. Turn on your new replaced two pole 220-volt breaker.