[Code of Federal Regulations] [Title 30, Volume 1] [Revised as of July 1, 2002] From the U.S. Government Printing Office via GPO Access [CITE: 30CFR7.65] [Page 27] TITLE 30--MINERAL RESOURCES CHAPTER I--MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR PART 7--TESTING BY APPLICANT OR THIRD PARTY--Table of Contents Subpart D--Multiple-Shot Blasting Units Sec. 7.65 Critical characteristics. The following critical characteristics shall be inspected or tested on each blasting unit to which an approval marking is affixed: (a) The output current. (b) The voltage cut-off time. (c) The components that control voltage and current through each making and breaking electric contact. (d) Operation of the visual indicator and the firing switch.