{"data":{"id":"us/30-cfr-57.6407","jurisdiction":"us","citation":"30 CFR 57.6407","heading":"Circuit testing.","body":"A blasting galvanometer or other instrument designed for testing blasting circuits shall be used to test the following:\n(a) In surface operations—\n(1) Continuity of each electric detonator in the blasthole prior to stemming and connection to the blasting line;\n(2) Resistance of individual series or the resistance of multiple balanced series to be connected in parallel prior to their connection to the blasting line;\n(3) Continuity of blasting lines prior to the connection of electric or electronic detonator series; and\n(4) Total blasting circuit resistance prior to connection to the power source.\n(b) In underground operations—\n(1) Continuity of each electric detonator series; and\n(2) Continuity of blasting lines prior to the connection of electric or electronic detonators.","path":["Title 30—Mineral Resources","CHAPTER I—MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR","SUBCHAPTER K—METAL AND NONMETAL MINE SAFETY AND HEALTH","PART 57—SAFETY AND HEALTH STANDARDS—UNDERGROUND METAL AND NONMETAL MINES","Subpart E—Explosives"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-30.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:25:24Z","sha256":"04354f5a9653acce03e850cf9229f0a5bb0717f9584ef4343c9cd2ec73e18a69","source_id":"us-cfr","stale":true,"prev":"us/30-cfr-57.6406","next":"us/30-cfr-57.6500"},"notice":"GroundRules: Original legal text. Not legal advice."}