30 CFR § 7.65 - Critical characteristics.
§ 7.65 Critical characteristics.
The following critical characteristics shall be inspected or tested on each blasting unit to which an approval marking is affixed:
(a) The output current.
(b) The voltage cut-off time.
(c) The components that control voltage and current through each making and breaking electric contact.
(d) Operation of the visual indicator and the firing switch.