PDFWAC 296-52-67230
Initiating systems.
Electric systems.
(1) Safety switch. A safety switch must be:
(a) Placed at intervals in the permanent firing line when firing from a power circuit.
(b) Made:
(i) So it can only be locked in the "off position"; or
(ii) With a short-circuiting arrangement of the firing lines to the detonator circuit.
(2) Lighting gap. A lighting gap must be:
(a) At least five feet ahead (in the firing system) of the main firing switch, between the switch and power source.
(b) Bridged by a flexible jumper cord just before firing the blast.