The detectors and cabling are to be installed in nine cells beneath the court.
The Local Democracy Reporting Service said HM Prison and Probation Service had committed to ensuring all prison accommodation met fire safety standards by 2027, after a review found about a quarter of occupied prison places did not comply.
According to National Audit Office figures, external published in 2024, that equated to about 23,000 prison places.
In its application, the MoJ said the works had been designed to minimise any impact on the historic building while improving safety.
Planning officers stated the cells were an important part of the court’s historic function in the administration of justice.
However, they said the proposed alterations would be “minimal”, with cabling following existing routes where possible.
Officers said: “There is public benefit. The submission explains the necessity of the works and reasonably justifies the approach.”
Designed by architect John Carr, York Crown Court was built in the 1770s and forms part of the York Castle complex.
