30 CFR Part 57Public Domain
§ 57.6404 — Separation of blasting circuits from power source
Subpart E — Explosives
(a)Switches used to connect the power source to a blasting circuit shall be locked in the open position except when closed to fire the blast.
(b)Lead wires shall not be connected to the blasting switch until the shot is ready to be fired.
Public Domain: 30 CFR Part 57 (MSHA Safety and Health Standards — Underground Metal and Nonmetal Mines) is a U.S. government publication and is not subject to copyright. Text extracted from the official source ↗. Figures are served from the eCFR; if one does not load, use the link in its place.