Fire control received a number of calls to a static caravan on fire near to St Giles on the Heath on July 30 at around 10.50pm.
Control mobilised one fire appliance from Holsworthy and two fire appliances from Launceston (Cornwall FRS).
Once crews were on scene, they confirmed the caravan to be well alight and were getting to work with two breathing apparatus but were struggling with access and water supply issues.
At 11.37pm crews were still using two breathing apparatus. Two 47kg propane cylinders were removed from the risk area.
Crews confirmed electricity to the caravan has been isolated and two fire appliances were doing a water shuttle for the appliance supplying water to the fire.
Crews finally confirmed one static caravan was completely destroyed by fire. Crews used two breathing apparatus and two hose reel jets.
A spokesperson added: “BT have been informed due to a BT pole being damaged by fire. This fire was confirmed as accidental activation.”