[Code of Federal Regulations]
[Title 30, Volume 1]
[Revised as of July 1, 2002]
From the U.S. Government Printing Office via GPO Access
[CITE: 30CFR7.66]

[Page 27]
 
                       TITLE 30--MINERAL RESOURCES
 
  CHAPTER I--MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR
 
PART 7--TESTING BY APPLICANT OR THIRD PARTY--Table of Contents
 
                 Subpart D--Multiple-Shot Blasting Units
 
Sec. 7.66  Output energy test.

    (a) Test procedures. The blasting unit shall be tested by firing 
into each of the following resistive loads, within a tolerance of 
1%:
    (1) The maximum blasting circuit resistance.
    (2) Any resistive load between 3 ohms and the maximum blasting 
circuit resistance.
    (3) One ohm.
    (b) Acceptable performance. (1) The voltage shall be zero at the 
firing line terminals 10 milliseconds after operation of the firing 
switch.
    (2) The electric current from the blasting unit shall be:
    (i) Less than 50 milliamperes except during firing of the blasting 
unit.
    (ii) Available only through the firing line terminals.
    (iii) At least an average of 2 amperes during the first 5 
milliseconds following operation of the firing switch.
    (iv) Not exceed an average of 100 amperes during the first 10 
milliseconds following operation of the firing switch.