A police officer has been hurt in a small explosion at an electricity sub-station in Pontypridd.
South Wales Police said officers were sent to the Brown Lennox Retail Park after an alarm was triggered and power failures were experienced in the area.
The officer was injured when he arrived at the scene and was taken to Royal Glamorgan Hospital. His injuries are not thought to be serious.
Two men of 33 and 34 have been arrested on suspicion of attempted burglary.
Police said that it appeared the sub-station explosion resulted from damage to an electricity generator.
Enquiries and repairs continue and some electricity supplies in the retail park have been affected, a spokesman said.
A spokesman for Western Power Distribution said 594 customers experienced a power cut just after 0900 BST due to the fire at the sub-station.
Power was restored after a half hour break, said the company.
Three crews from South Wales Fire Service were called to the blaze.
A police cordon around the area has now been lifted.