[Code of Federal Regulations] [Title 49, Volume 5] [Revised as of October 1, 2005] From the U.S. Government Printing Office via GPO Access [CITE: 49CFR393.23] [Page 393] TITLE 49--TRANSPORTATION DEPARTMENT OF TRANSPORTATION PART 393_PARTS AND ACCESSORIES NECESSARY FOR SAFE OPERATION--Table of Contents Subpart B_Lamps, Reflective Devices, and Electrical Wiring Sec. 393.23 Power supply for lamps. All required lamps must be powered by the electrical system of the motor vehicle with the exception of battery powered lamps used on projecting loads. [70 FR 48046, Aug. 15, 2005]