West Sussex Fire and Rescue Service were called 6.50pm to reports of the explosion which knocked down a wall in Market Road, Chichester, near the Coral bookmakers. Click to read eyewitness accounts of what happened.
At 6.52pm, the fire service were also called to Lakeside Caravan Holiday Park in Vinnetrow Road, Chichester after an overhead power line was seen sparking. The incidents have been linked by the fire service.
As a result of the Chichester explosion, a 100-metre cordon was erected around the substation and buildings in that radius were evacuated. A taxi firm staff member working nearby said they were told to stay inside their office. Click to read more.
Roads closed included The Hornet from Needlemakers, and Market Road, to the junction with Calendonian Road. The cordon was lifted when Market Road was reopened at 9.30pm, and people were allowed back into the buildings.
Power was lost to 1,718 homes in the area, but the power supply has been restored from the power network being redirected, a spokesman for electricity company SSE said.
The fire service sent two appliances to the sub-station and two to the holiday park.
At the holiday park, there was no fire so crews made sure the area was safe and have been stood down there.
In the city centre, fire crews stayed at the scene to make sure the substation did not set alight. They would not put it out due to the serious risk of electrocution, a fire service spokesman said, but would let it burn itself out.
The last crews left the scene at around 22.30pm and a fire officer stayed behind to liaise with SSE until 11.30pm.
The investigations and repair work have been handed over to SSE, a fire service spokesman said.
Emergency teams would be working throughout the night to run tests and complete safety work to see how the explosion happened and make sure it did not happen again, an SSE spokesman said.
He said safeguards would be in place in the immediate vicinity of the substation to make sure people nearby were not in danger tomorrow morning.