Does "no power" mean no 12v or no 120vac, or both? The breakers are for 120v shore power and supply wall outlets and a few appliances. Everything else is 12v and gets its power from battery, or the converter while plugged to shore power. 12v circuits will have fuses rather than breakers in nearly all cases.
Many things in an RV need 12v power to work, even if using 120v shore power as the main source. The circuit boards in appliances, for example, use 12v power all the time.
2004 American Tradition; 2014 Buick LaCRosse
Homebase in the Ocala Nat'l Forest near Ocala, FL