Four fire engines and around 25 firefighters tackled a fire at an industrial unit on Tariff Road in Tottenham.
A small part of an electrical room on the ground floor of a single-storey industrial unit was damaged by the fire. One woman was taken to hospital.
The Brigade was called 0101 and the fire was under control at 0245. Fire crews from Edmonton, Tottenham and Walthamstow fire stations attended the scene.
The fire is believed to be accidental and caused by an electrical fault.