Electrician,Meyer Electrical Services Inc.
Written by Walt Meyer

Getting Your Home the Right Standby Generator Size – Part 2

Part 2 will discuss Kilowatts & ATS, Running Watts & KVA, and Selecting a Standby Generator.

Kilowatts & ATS

The size of a standby generator is determined by its output of kilowatts (kW). A kilowatt is 1,000 watts, and so a 20kW generator produces 20 kilowatts, 20,000 watts of electrical power.

Every generator must be paired with an automatic transfer switch (ATS), which activates and deactivates the standby-power system. For example, a standby generator connected to a 200-amp breaker panel will require a 200-amp ATS.

Running Watts & KVA

Proper generator size will ultimately be determined by calculating the total running watts and starting KVA of all the circuits, appliances, and electrical machines connected. A calculation for each must be made.

Basically, KVA equals 1,000 volt-amps, a volt being electrical pressure and amp being electrical current. Knowing the starting KVA is required because every time an electrical motor turns on, it creates an additional electrical surge the generator has to be capable of handling. Running watts is the power being consumed by an electrical machine while normally functioning.

After the identification of standby electrical circuits, the electrician will be able to sum up the total running watts and starting KVA to calculate the total electrical load for the whole system. Only then will an electrician be able to accurately determine the correct size of the standby generator.

Selecting a Standby Generator

The first step is contacting a licensed electrician who is an expert in standby generators and asking for a site survey. This will include an inspection of your house’s electrical panel and circuits, along with a discussion regarding the appliances and electrical machinery you want powered.

As previously discussed, a load calculation and then the right size of the generator will be determined. Afterwards, the type of generator (air-cooled or liquid cooled), how it will be powered (LP or natural gas), installation location, and other options will be chosen. The electrician will then provide an estimate for review and discussion prior to moving forward on the project.

Electrical Services You Can Trust

Meyer Electrical Services is an authorized Generac and KOHLER Sales &
Service Dealer serving Maryland, Virginia, and D.C. We provide custom standby generator installations and are trained and licensed to perform the regularly required important factory service and maintenance. Receive a free consultation today by calling (301) 941-1400.