30 CFR 56.6407 - Circuit testing.
A blasting galvanometer or other instrument designed for testing blasting circuits shall be used to test each of the following:
(a) Continuity of each electric detonator in the blasthole prior to stemming and connection to the blasting line.
(b) Resistance of individual series or the resistance of multiple balanced series to be connected in parallel prior to their connection to the blasting line.
(c) Continuity of blasting lines prior to the connection of electric detonator series.
(d) Total blasting circuit resistance prior to connection to the power source.