An investigation has begun after parts of central Liverpool lost their power supply.
The power cut happened just before 1200 BST on Friday.
Shops and offices were affected for just a few seconds.
But the power failure caused a number of problems for computer systems and shop cash registers.
Some stores had to close while workers tried to get their systems back to normal.
Train services on Merseyrail were also affected and delays of about 15 minutes were expected throughout the afternoon.
A spokesperson for Manweb said a brief fault on the main power line into Liverpool city centre caused the short cut in supplies.
They added that the problem had since been repaired.