Four fire engines and around 25 firefighters attended a fire on Carshalton Road in Woodmansterne.
The roof and rear of a static caravan was damaged by fire. A plastic shed was also damaged. There were no reports of any injuries.
The Brigade's Control Officers received six calls about the fire.
The first call was received at 2346 and crews from Sutton, Wallington and Croydon fire stations attended the scene. The fire was extinguished by 0052.
The fire is believed to have been caused by a fault with a mini-fridge.
A London Fire Brigade spokesperson said: “If your white goods start making a strange noise, don’t ignore it. If you think there’s a problem always unplug it and contact the manufacturer or a qualified repair technician.
“Most fires where white goods are the source of ignition are not down to anything you have done – so always make sure you register your appliances as you’ll be informed if any issues are identified with the product you’ve bought.”