(a) When loading or charging blast holes with electric detonators, all electric power within an unsafe distance of the place to be blasted shall be deenergized.

(b) Electric blasting with blasting machines or special circuit is permissible. With blasting machines, connections shall be made in series or in a combination connection recommended by the manufacturer. With power currents, connections shall be made in series, parallel, or a combination of the two.

(c) When blasting is by means of a special blasting circuit, no one shall enter the place in which the blasting has been done until the permanent blasting wires have been disconnected from the source of electrical energy and the blasting switch has been locked in the open position.

(d) The person responsible for blasting shall be in charge of the blasting machine when it is in the pit. No other person shall connect the blasting machine to the leading wires, and such connection shall not be made until the area has been made safe preparatory to the firing. An audible warning shall be sounded prior to the blasting.

(e) Electric current from power circuits shall not be used for firing shots in a pit except when the electric connections to power circuits are made within the enclosed switch box described in these rules.

(f) Permanent blasting lines shall be kept well in the clear from all power circuits and from all pipes, rails, etc., and shall be run or strung at least 20 feet away from all power circuits.

(g) Grounded circuits or systems shall not be used for electrical blasting.

(h) Permanent blasting lines, safety switches, and blasting switches shall be maintained by a competent electrician or other competent and experienced person.

(i) Leading wires from portable generating blasting devices or approved type batteries shall be not less than those recommended by the Institute of Makers of Explosives.

(j) Permanent blasting wires shall be so installed and maintained that they provide the current capacity required by the electrical firing device. All such wires shall be in conduit, shall consist of type "S" cable or equivalent or shall consist of two rubber covered wires strung on glass insulators or porcelain knobs. If rubber covered wires are used, they shall be kept at least five inches apart.

(k) Connecting wires shall be not less than those recommended by the Institute of Makers of Explosives.

(l) At the location where the shot firing is to be controlled, there shall be installed a suitable blasting circuit enclosed externally operated pole switch with the handle or lever arranged to be locked in the "off" position only.

(m) Where the blasting lines run to a single face to be blasted, a "safety" switch of the same type as required for the blasting switch shall be installed between the switch and the face. This switch shall be installed in a safe location guarded from flying rock.

(n) Where a single blasting switch is used for several blasting circuits, a safety switch shall be installed in each circuit immediately adjacent to the blasting switch. In addition, a second safety switch shall be installed in the circuit adjacent to the area to be blasted.

(o) A blasting galvanometer or circuit tester especially designed for blasting work shall be used for testing.

(p) Leg wires of electric detonators shall be kept short circuited by means of a short-circuiting device or by twisting the ends of the leg wires together, except that the short-circuiting devices may be removed temporarily for the purpose of testing detonators with the galvanometer.

(q) Before connecting the temporary wires to the leg wires or bus wires, the ends of the temporary wires that are to be connected to the safety switch shall be "shorted" by being twisted together. The man making or supervising the connection at the face must have the "shorted" ends of the temporary wires in his possession, and, after making the connections at the face, he shall run the temporary wires to the safety switch. He shall never attach the temporary wires to the safety switch before attaching them to the leg wires or bus wires.

(r) At the safety switch, said man shall untwist the temporary wires, unlock the safety switch, attach the temporary wires to the safety switch and then place the safety switch in the "on" position. He shall then proceed or signal to a designated person at the blasting switch, and he or such designated person shall unlock the blasting switch, throw it in the "on" position to fire the shot, then immediately return the blasting switch to the "off" position and lock it in that position. After blasting, no one shall go nearer the face that has been blasted than the safety switch until the safety switch has been opened, the temporary wires disconnected, and the safety switch locked in the "off" position.

(s) Loading and charging of blasting holes shall cease upon the approach of an electrical storm and shall not resume until conditions are safe. All persons shall be removed a safe distance from the charged area until conditions are safe.

(t) The minimum necessary number of persons shall be at the loading places when making the blasting connections. All other persons shall be a safe distance away from the loading place when blasting connections are made.