To prepare an electric firing system, take these steps:

• STEP 1. After finding a safe firing position and a place for the charge, lay out the firing wire from the charge position to the firing position. Before leaving the charge position, anchor the firing wire to something. Always keep the firing device with you. Do not leave it at the firing position.

• STEP 2. Check the firing wire with the galvanometers or circuit taster to make sure it does not have a short circuit or a break. This is best done with one man at each end of the firing wire.

• To check for a short, separate the two strands (the bare ends) of the firing wire at the firing position. Have the other soldier do the same thing with the other end of the wire at the charge position. At the firing position, touch the bare ends of the two strands to the galvanometer/circuit tester posts. The needle on the galvanometers should not move, nor should the light on the circuit tester come on. If the needle does not move or if the light does not come on, the wire has a break--replace it.

• If the wire has no short when tested, test it for a break. Have the soldier at the charge position twist the bare ends of the strands together. Then touch the two strands at the firing position to the galvanometers/circuit tester posts. That should cause a wide deflection of the galvanometer needle or cause the circuit tester light to come on. If the galvanometers needle does not move or if the light does not come on, the wire has a break--replace it.

• STEP 3. At the firing position, check the blasting cap with a galvanometers or circuit tester to make sure it does not have a short. Remove the short circuit shunt and touch one cap lead wire using the galvanometers, the needle should make a wide deflection. If it does, the cap is good.

• If the needle fails to move or only makes a slight deflection, replace the cap.

• When using the circuit tester, the light should come on when the handle is squeezed. If it does not replace the cap.

• STEP 4. Move to the charge position and, if the charge is a block of TNT, clear its cap well if the charge is a block of C4 plastic explosive, push a hole in it about the size of a blasting cap.

• STEP 5. Position the charge. Then splice the lead wires of the cap to the, firing wire (pigtail knot).

• STEP 6. Insert the cap into the cap well of the TNT and secure it with the priming adapter, or insert the cap into the hole made in the C4 and mold the explosive around the cap.

• STEP 7. Move back to the firing position and check the wire circuit with the galvanometers or circuit tester (same technique as described earlier).

If the circuit checked out and the blasting machine does not set off the charge, there is a misfire.

If an untamped charge misfires, investigate at once. If the charge is tamped, wait 30 minutes before investigating, then take these steps:

• STEP 1. Check the firing wire connection to the blasting machine to be sure that the contacts are good.

• STEP 2. Make two or three more attempts to fire the charge.

• STEP 3. Try to fire it again using another blasting machine.

• STEP 4. Disconnect the firing wire from the blasting machine and shunt (twist together) the ends of the wire.

• STEP 5. Move to the charge position to investigate. Take the blasting machine with you.

• STEP 6. Check the entire circuit, including the firing wire, for breaks and short circuits.

• STEP 7. Make no attempt to remove the primer or the charge.

• STEP 8. If the fault has not been found, place a new primed charge beside the misfire charge.

• STEP 9. Disconnect the old blasting cap wires from the firing wire and shunt the ends of the blasting cap wires.

• STEP 10. Attach the new blasting cap wires to the firing wire and fire the new charge. This should also detonate the misfire charge.