MSHA - Code of Federal Regulations - 30 CFR 7.68
30 CFR § 7.68
Firing line terminals test.
(a) Test procedures. (1) The contact resistance through each
firing line terminal shall be determined.
(2) A 10-pound pull shall be applied to a No. 18 gauge
wire that has been connected to each firing line terminal according to the
(b) Acceptable performance. (1) The contact resistance shall
not be greater than 1 ohm.
(2) The No. 18 gauge wire shall not become disconnected
from either firing line terminal.