Fire crews were called to a home in York early this morning.
There was a smell of burning and fire alarms were going off at the property on Sixth Avenue.
Acomb and York crews went to the incident at 1.21am.
A North Yorkshire Fire & Rescue Service spokesperson said: “Upon arrival and investigation they found there to have been a small fire affecting electrical wiring to a immersion heater.
“Crew isolated heater at fuse board, inspected using a thermal imaging camera and provided advice to occupants.”