Main Breakers, Disconnects, and Transfer Switches

Main Breakers:

Main breakers are generally found inside of the breaker panel in a home or business.It is a larger breaker, designed to shut down power to the breaker panel and all ofthe electrical circuits being powered from the panel. When the main breaker fails ortrips, you will likely be experiencing a complete power outage. If the main breaker
trips or won’t reset properly, there is likely a very good reason. You should contact a licensed electrician immediately to evaluate the situation. Remember, the main breaker usually controls the power for the entire electrical system.

If a main breaker is difficult to reset, leave it alone. Never attempt to force a tripped main breaker to reset, unless you are a qualified licensed electrician.


Disconnects are used to shut-off power to a main electrical component (breaker panel), or to a specific piece of equipment (A/C condensers, pool equipment). It is essentially a switch that kills power to a system or an isolated piece of equipment.Main disconnects are often used in multi-residential properties. These disconnects will usually be located in an area slightly away from the structure it is protecting. A disconnect allows power to be turned off to that structure from a location outside of the home or business, in case of an emergency. Disconnects or required by some City Inspection Departments.

To provide safety and control for repairmen, external A/C disconnects are required for each condensing unit, unless the main electrical panel is within close proximity.


In residential and commercial service, transfer switches are used primarily when a generator has been connected to the electrical system of a home or business. The transfer switch allows selection of how the power will be supplied to the main electrical system of the structure. For instance, a transfer switch can enable the selection of a generator as the main power supply, instead of the local power delivery company lines. The transfer switch makes it possible to switch back and forth between power supplies as needed. This can be done automatically or manually, depending upon the type of switch used, and the design of the system. Some automatic transfer switches have the capability to select between multiple power sources (power company, generator, solar, or batteries) to ensure power supply to the home or business is uninterrupted. Improper installation of a transfer switch can create a very dangerous situation, and should only be performed by a professional that has been trained in this specific type of installation.