Warning devices shall be labeled so that their purpose is easily identified. An easily visible warning device light labeled with the words "X-RAY ON," or words having a similar intent, shall be located near any switch that energizes an x-ray tube and shall be illuminated only when the tube is energized. This warning light shall be of a fail-safe design.
S.C. Code Regs. § 61-64.VIII.RHB 8.5