30 CFR § 56.6600
If extraneous electricity is suspected in an area where electric detonators
are used, loading shall be suspended until tests determine that stray current
does not exceed 0.05 amperes through a 1-ohm resister when measured at the
location of the electric detonators. If greater levels of extraneous
electricity are found, the source shall be determined and no loading shall
take place until the condition is corrected.
[58 FR 69596, Dec. 30, 1993]