[Code of Federal Regulations] [Title 49, Volume 4] [Revised as of October 1, 2005] From the U.S. Government Printing Office via GPO Access [CITE: 49CFR234.241] [Page 575] TITLE 49--TRANSPORTATION CHAPTER II--FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PART 234_GRADE CROSSING SIGNAL SYSTEM SAFETY--Table of Contents Subpart D_Maintenance, Inspection, and Testing Sec. 234.241 Protection of insulated wire; splice in underground wire. Insulated wire shall be protected from mechanical injury. The insulation shall not be punctured for test purposes. A splice in underground wire shall have insulation resistance at least equal to that of the wire spliced.