What Wires to Break to Shut Down an AC Unit During a Fire Alarm

Purpose

• Breaking the wiring to shut down an air conditioner is an emergency procedure that can help contain fire to a single room or part of your home. For example, a small kitchen fire may be easy to put out with a fire extinguisher. However, if the fire enters a nearby air conditioning duct and its extreme heat is blown to another room, combustible materials there can ignite, spreading the fire more quickly than you can control. Without a constant flow of electricity, an air conditioner's fans can't run, eliminating this issue.

Electrical Wiring

• One of the easiest ways to shut down power to an air conditioner is by unplugging or physically breaking the wires that carry electricity to the control unit. In the case of window- and wall-mounted AC units, unplugging them from a wall outlet is a safe way to break the flow of electricity. However, breaking the high voltage wire that carries electricity to a central AC unit can result in electric shocks or electrical fires and should be avoided even in the event of an emergency.

Circuit Breakers

• Circuit breakers and fuse boxes provide a much safer way to break wires and shut down an AC unit during a fire alarm. Breakers, which are more common in new homes, feature individual switches that open wiring and shut off power to entire portions of the home. Fuse boxes feature screw-in or press-in fuses that complete household circuits; unscrewing the right fuse will break the circuit and cause everything it controls to shut down. Label your breakers or fuses, including the one that leads to the central AC unit, for quick shutoff in an emergency.

Considerations

• Circuit breakers are often located in basements or other remote areas of the home, which means that it may take time to safely shut down an air conditioner in an emergency. Shutting down the AC unit to prevent the spread of fire is only useful in cases of small, manageable fires. Larger fires, or those that begin to spread through air conditioning or heating ducts, are cause for evacuation.