Standby generator

{{Short description|Type of generator}}

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image:FEMA - 40330 - Photograph by Ashley Andujar taken on 03-26-2009 in Puerto Rico.jpg

A standby generator is a back-up electrical system that operates automatically.Robert B. Hickey Electrical Construction Databook, McGraw Hill, 2002 {{ISBN|0-07-137349-7}}, Chapter 14 Within seconds of a utility outage an automatic transfer switch senses the power loss, commands the generator to start and then transfers the electrical load to the generator. The standby generator begins supplying power to the circuits.{{cite book|page=325|title=AC Power Systems Handbook, Third Edition|author=Jerry C. Whitaker|date=26 September 2006 |publisher=Taylor & Francis |isbn=0849340349}} After utility power returns, the automatic transfer switch transfers the electrical load back to the utility and signals the standby generator to shut off. It then returns to standby mode where it awaits the next outage. To ensure a proper response to an outage, a standby generator runs weekly self-tests. Most units run on diesel, natural gas, or liquid propane gas.{{cite web|title=Backup Power for the Individual and Volunteer, Part I: Generators|url=https://www.disaster.com/backup-power-for-the-individual-and-volunteer-part-i-generators/|accessdate=January 6, 2015|date=December 8, 2014|author=Zachariah Amela}}

Automatic standby generator systems may be required by building codes for critical safety systems such as elevators in high-rise buildings, fire protection systems, standby lighting, or medical and life support equipment.{{cite book|page=304|title=Nursing Home Federal Requirements: Guidelines to Surveyors and Survey Protocols|edition=7th|author=James E. Allen|isbn=978-0826107909|year=2010|publisher=Springer Publishing Company}}

In 2002, approximately 0.63% of homes in the United States had installed a backup generator; that figure rose to approximately 5.77% by 2023.Laura Daily, [https://www.washingtonpost.com/home/2023/08/29/home-standby-generator-cost-power/ What to know before investing in a standby home generator], Washington Post (August 29, 2023). The wattage of typical whole-home generators varies from 7.5 kW to 26 kW.