30 CFR § 56.6401
Shunting.
Except during testing--
(a) Electric detonators shall be kept shunted until connected to the blasting
line or wired into a blasting round;
(b) Wired rounds shall be kept shunted until connected to the blasting line;
and
(c) Blasting lines shall be kept shunted until immediately before blasting.
[58 FR 69596, Dec. 30, 1993]