The alarm was raised to the fire, out in the open, on Granville Road, just before 11pm on Wednesday.
Firefighters battled for over an hour and a half to get the blaze under control.
Shropshire Fire and Rescue Service sent a fire crew from Newport and the incident support unit from Wellington to the scene.
A spokesman said there had been multiple seats of fire caused by someone deliberately burning cables and wiring.
The fire was under control by 12.40am on Thursday.