Shropshire Fire and Rescue Service scrambled two appliances from Bridgnorth and Much Wenlock at 9.24am after receiving reports of a "hole in the pavement following explosion."
They initially classified the incident as a gas leak and sent an operations officer to join responders from gas, and electricity providers in investigating.
But a spokesperson for gas supplier Cadent confirmed it "was an electrical fault, Cadent will be handing over to Western Power Distribution" before leaving the site.
A spokesperson for WPD said the incident was "caused by an underground cable fault, which resulted in a small explosion. No one was hurt."
They said that it has been reported at 9.24 am and affected 39 customers.
"Engineers from Western Power Distribution are now at the scene where they have begun work to repair the fault. Power supplies to all customers are expected to be restored by 1pm.
"We apologise for any inconvenience caused while repairs are carried out."
Andy Corfield, landlord at the Crown pub in High Street, said: "I was putting away my deliveries this morning. I had gone back upstairs and heard a loud bang.
"I looked outside and saw the bakery were just getting their delivery in, and I thought that someone had dropped some pallets."
But he added: "My other half called up and said that half our lights went out, and outside a manhole cover had blown off, and some of a paving stones were up as well.
"Because of what happened a couple of years ago I thought I had better call the fire brigade, and they were here very quick."
Another witness who did not wish to be named said businesses were briefly evacuated.
Bridgnorth town mayor Councillor Sarah Barlow praised the emergency services for their speedy response. No-one was believed to be hurt.
"All I know is that there was a small explosion," said Councillor Barlow, who is recovering after having Covid for 10 days.
"The pavement was cracked outside one of the shops."
But she said the emergency services for responding.
"Thankfully nobody was hurt," she said. "I have nothing but praise for the emergency services and the way that they responded."
It is not the first time Bridgnorth has been disrupted in this kind of way.
In May 2019 a gas leak lead to the evacuation of buildings and several residents had to be housed for the evening by Bridgnorth Town Council.
In that incident the fire service said a fault in an electrical cable sat above the gas pipe caused a small explosion which ruptured the gas main. Luckily the gas was not ignited.
But Councillor Barlow said she believed the two incidents were probably coincidental.
By 11am today the emergency services had gone, but that work was still ongoing to restore electrical power to some businesses.
At 10.20am police confirmed that the road was open again, thanking people for their patience.