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Subchapter 7. General Industry Safety Orders
Group 18. Explosives and Pyrotechnics
Article 116. Handling and Use of Explosives--Blasting Operations

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§5299. Firing with Electricity--General.

(a) Before adopting any system of electrical firing, the licensed blaster shall conduct a thorough survey for extraneous currents, and all dangerous currents shall be eliminated before any holes are loaded. No electric blasting or preparation for electric blasting shall be done when stray electrical currents exceed 0.05 amperes.

Exception: Specialty electric blasting caps used as recommended by the manufacturer.

(b) Electric firing shall be done only with devices designed for initiating electric detonators.

(c) Electric detonators to be fired with blasting machines shall be connected in accordance with the number and circuitry limitations recommended by the machine or detonator manufacturer.

(d) Devices used for igniting electric detonators shall not cause arcing in the detonators. A circuit interrupter shall be used when arcing is a problem.

(e) All blasting wires shall be kept clear of electric lines, pipes, rails, and other conductive materials.

(f) That part of the blasting circuit leading from the firing switch to the blast area shall not be grounded.

(g) All low-voltage electric power lines within 50 feet of the holes to be loaded shall be removed or de-energized before an electric detonator or starter is brought into the blast area. Where this is not practical, a check for stray current shall be made with a proper instrument.

(h) The blasting circuit shall be tested with a blasting galvanometer or other device designed to test blasting circuits before firing the round.

(i) The blasting circuit shall remain shorted until the round is ready to test and fire.

(j) Electric detonators of different brands shall not be used in the same round.

(k) Where light and power circuits are used for blasting, keys to the shot-firing and safety switches shall be kept by the licensed blaster. When necessary to make repairs, extensions, or tests on the blasting or shot-firing lines, the licensed blaster or blaster in training shall unlock and remain at the switch until he or she relocks the switches or designates that responsibility to someone who reports back to the licensed blaster with the keys when work is completed. No preparations for loading or blasting shall be done until all switches are relocked and the keys back in the possession of the licensed blaster. At the end of the shift, the licensed blaster shall give the keys to the licensed blaster of the following shift. A duplicate set of keys should be kept by the superintendent under lock and key in the office. There shall be no other set of keys fitting these locks on the job site.

(l) Mobile radio transmitters shall be de-energized and effectively locked when less than 100 feet from electrical blasting caps that are not in their original container.


Electric Detonators

    Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.  

1. Amendment of subsection (c) filed 3-28-75; effective thirtieth day
thereafter (Register 75, No. 13).

2. Amendment of subsection (a) filed 10-17-75; effective thirtieth day
thereafter (Register 75, No. 42).

3. Repealer of subsection (a) and relettering of existing subsections filed 3-
7-80; effective thirtieth day thereafter (Register 80, No. 10).

4. Amendment filed 7-11-2003; operative 8-10-2003 (Register 2003, No. 28).

5. Change without regulatory effect providing more legible diagrams filed 3-2-
2009 pursuant to section 100, title 1, California Code of Regulations 
(Register 2009, No. 10).

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