SERIES PARALLEL FIRING OF EBW DETONATORS
It is possible to function more than one EBW detonator from a single firing module by wiring the detonators in various parallel-series combinations. The following table shows the number of detonators that can be fired on each leg of a series-parallel circuit from the RISI FS-10, FS-17 or FS-43 fireset.
For example, with 50 feet of blasting wire (P/N 167-8559), 6 detonators can be placed at the end of each leg of 3 parallel legs for a total of 18 detonators per shot. If greater firing distances are required, RISI “C” cable (P/N 162-2669) can be substituted for the blasting wire on a three to one ratio i.e., 300 feet of “C” cable is equivalent to 100 feet of blasting wire.
Some precautions that should be observed are:
- Each parallel leg should have approximately the same circuit characteristics.
- Different model detonators should not be used on the same test.
- Excessive cable lengths between the detonators on a series string should be avoided.
- All parallel legs MUST terminate at the Firing Module. No trunk cable.
Before performing a “crucial” experiment, a trial shot should be performed with CVR’s or CVT’s to determine whether there is sufficient current for this many detonators. If this equipment is not available, a trial firing with one more detonator or firing leg than is planned for the actual experiment will generally assure an adequate safety factor.
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