30 CFR § 56.6407
A blasting galvanometer or other instrument designed for testing blasting
circuits shall be used to test 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
(c) Continuity of blasting lines prior to the connection of electric detonator
(d) Total blasting circuit resistance prior to connection to the power source.
[56 FR 46501, Sept. 12, 1991; 56 FR 52193, Oct. 18, 1991; 58 FR 69596, Dec. 30, 1993]