Two highways near Wellington are to close on overnight on Sunday so a large transformer can be transported to the Haywards Hill substation.
State Highway 2 will have diversions in place and State Highway 58 will have lane closures. Electronic signs will be used to keep motorists informed.
The closures will start at 10pm on Sunday and are due to last until 4am on Monday.
Similar closures will be in place a week later.
