In generator mode, the backfeed breaker is on, accepting power from the generator into the panel, and the main breaker is off, isolating the external mains. The generator feeds the home by [[backfeeding]] the panel, but the panel cannot backfeed the external mains. [[Backfeeding]] the external mains is unsafe and illegal, because it can potentially [[electrocution|electrocute]] [[lineworker]]s, start fires, and overload or damage the generator.<ref>http://www.nooutage.com/interlock_kits.htm</ref>
==Installation and Operation==
AEarly generator interlock kitkits isconsisted of two sliding [[steel]] or [[plastic]] (depending on the brand) plates held together by three bolts and installed on the front cover of the home's [[distribution board|breaker panel]]., Ithowever, consistssome models made by Eaton (formerly Cutler-Hammer) and Siemens for panels manufactured by them install on the adjacent circuit breakers themselves and consist of twoa sliding [[steel]]arm for breakers installed back-to-back or [[plastic]]a (dependingpivoting arm for breakers that are installed side-by-side or one above the other, these arrangements remain on the brand)breakers plateseven heldif togetherthe bypanel threecover boltsis removed as opposed to the mechanisms installed on the panel covers.. When movedthe downmain breaker is turned on, the plate or pivot arm blocks the generator backfeed [[circuit breaker]] and allows the main [[circuit breaker|breaker]] to remain on;. when moved upConversely, when the generator backfeed [[circuit breaker]] may beis turned on, but the main [[circuit breaker]] is blocked and will remain off. The generator backfeed [[circuit breaker]] is connected to a generator inlet installed (preferably) on the outside of the structure. A short cord connects the generator to the house inlet, usually through a [[industrial and multiphase power plugs and sockets|twistlock]] [[AC power plugs and sockets|plug and socket]].
