14 C.F.R. § 23.1381 Instrument lights.
Title 14 - Aeronautics and Space
The instrument lights must— (a) Make each instrument and control easily readable and discernible; (b) Be installed so that their direct rays, and rays reflected from the windshield or other surface, are shielded from the pilot's eyes; and (c) Have enough distance or insulating material between current carrying parts and the housing so that vibration in flight will not cause shorting. A cabin dome light is not an instrument light.
Title 14: Aeronautics and Space
PART 23—AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES
Subpart F—Equipment
Lights
§ 23.1381 Instrument lights.
