If there is a power outage, whether local or citywide, Jewish technicians may do what is necessary to restore power to all the area’s residents. This is because many areas have sick people whose lives would be at risk without the electric equipment they need. Because of the possibility of loss of life, the area’s electricity supply must be restored. Moreover, since the restoration is permissible, all residents of the neighborhood may benefit from it (above, 17:5). If there was food on the plata that cooled down while the electricity was off and then warmed up again when the electricity was restored, it may be eaten even if the food was not fully cooked beforehand, and only finished cooking after the electricity was restored, since it was cooked in a permissible manner.
If a small area lost electricity and it is clear that there is no risk to life involved, one may not restore the electricity. If the electricity was nevertheless restored, and as a result a light came on, one may not benefit from it. This means that anything that could not have been done without the light may not be done using the light (as explained in section 2 above). If food warmed up as a result of the electricity that was restored impermissibly, one must wait until it cools off before eating it. If food finished cooking as a result of this transgression, one may not eat it (R. Shlomo Zalman Auerbach cited in SSK ch. 32 n. 182; see above, 10:3).