BURLINGTON, Vt. (AP) - A federal court judge has scheduled a hearing on June 4 on a challenge by the owner of the Vermont Yankee nuclear power plant.

Entergy Corp. sued the state last month, saying regulators have delayed approval of a backup emergency diesel generator.

Yankee has been ordered by the U.S. Nuclear Regulatory Commission to install a backup power source by September.

Vermont Public Radio reports (http://bit.ly/Z1Zl3A) Yankee says it needs to start construction by June 11 to get the equipment on line by September.

The state Public Service Board hasn't granted a permit. In April, it said it is considering whether it can grant approval when Entergy "is not in compliance" with existing state orders covering Yankee's continued operation.

Information from: WVPS-FM