{{Short description|Type of generator}} {{refimprove|date=June 2011}}
[[image:FEMA - 40330 - Photograph by Ashley Andujar taken on 03-26-2009 in Puerto Rico.jpg|thumb|right|Standby generators]] A '''standby generator''' is a back-up electrical system that operates automatically.<ref name=Hickey02>Robert B. Hickey ''Electrical Construction Databook'', [[McGraw Hill Education|McGraw Hill]], 2002 {{ISBN|0-07-137349-7}}, Chapter 14 </ref> Within seconds of a utility [[Power outage|outage]] an automatic [[transfer switch]] senses the power loss, commands the generator to start and then transfers the [[electrical load]] to the [[Electric generator|generator]]. The standby generator begins supplying power to the [[Electrical network|circuits]].<ref>{{cite book|page=325|title=AC Power Systems Handbook, Third Edition|author=Jerry C. Whitaker|date=26 September 2006 |publisher=Taylor & Francis |isbn=0849340349}}</ref> After utility power returns, the automatic transfer switch transfers the electrical load back to the utility and signals the standby generator to shut off automatically. 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 fuel|diesel]], [[natural gas]], or [[propane|liquid propane gas]].<ref>{{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}}</ref>
Automatic standby generator systems may be required by [[building code]]s for critical safety systems such as elevators in high-rise buildings, [[Fire suppression system|fire protection systems]], standby lighting, or [[Advanced cardiac life support|medical and life support equipment]].<ref>{{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|Springer Publishing Company]]}}</ref>
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.<ref name=Daily2023>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).</ref> The [[wattage]] of typical whole-home generators varies from 7.5 [[Kilowatt|kW]] to 26 kW.<ref name=Daily2023/>
==See also== * [[Diesel generator]] * [[Electric generator]] * [[Emergency power system]] * [[Uninterruptible power supply]]
==References== {{reflist}}
[[Category:Power station technology]]