A standby generator is basically brain dead without an automatic transfer switch.
They are similar to the thermostat in your house. Instead of monitoring temperature, an automatic transfer switch monitors utility power.
When the power goes out, the automatic transfer switch tells the generator to start.
Air Conditioner Shedding
In the past, home standby generators couldnít power two central air conditioners because they would overload if both started at the same time. As a result, one air conditioner was always locked out.
There are two types of automatic transfer switches with A/C Shedding capability:
Load Center + AC Shedding
New sophisticated load centers will always energize 16 essential circuits during an outage.
Two of the circuits could be connected to central air conditioners, allowing either to start but not simultaneously.
Service Disconnect + A/C Shedding
A better option is to use a service disconnect switch to power the entire panel and lock out a few high-demand appliances instead.
If the system doesn't have enough juice, the service disconnect will lock out up to four individual HVAC loads, preventing them from starting.
In addition to the built-in A/C shedding functionality, you can install Power Management or Smart Management Modules (PMM)(SMM) that will manage up to 8 additional loads to cycle, so you'll never have to worry about those higher-voltage appliances tripping the system.