Copthorne Road will be closed for drivers leaving the town centre from Monday for one week while Western Power carries out work to reinforce its existing underground cables.
Work on the improvements started on October 12 and was initially carried out under two-way temporary signals. While the road is closed, traffic will be unable to join Copthorne Road from Frankwell roundabout.
The Mount and Shelton Road will be used as the diversion route from the Frankwell roundabout.
Access to all businesses and properties along Copthorne Road will remain possible from the Shelton Road end of Copthorne Road.
The existing underground cables were laid in 1964, and newer cables will be installed within the footway to allow for more capacity on Copthorne Road.
The work is supporting the Bellway Homes development and other future developments in the area by helping to ensure the increased demands put on the Western Power network is accommodated, and minimising the risk of any future outages or failures to their network.
It was requested that operatives work extended hours and over the weekends to help ensure that the disruption is kept to a minimum.
Residents, businesses and affected bus companies should have been notified of the works and proposed traffic management, and advanced warning signs were due to be placed on site.