Electric Blasting Cap

a device for detonating an explosive charge by means of an electric current. It consists of a detonator and an electric fuze in a single cartridge.

Current sources used to trigger electric blasting caps include shot exploders and, less often, power or lighting mains. Various designs use a bridge wire (widely used in the USSR), a current-conducting ignition charge, and spark discharges. Industrial types are classified according to operating time as instantaneous, short delay, and long-delay types. The detonator in instantaneous types is triggered directly by the electric fuze; in both delay types it is triggered through a delay composition. Depending on the purpose and the conditions of use, electric blasting caps may be classified as waterproof and nonwaterproof, permissible (for mines that are dangerous because of gas and dust) and nonpermissible, normal and low-sensitivity, antistatic, thermally stable (for use in the petroleum industry, where ambient temperatures reach 270°C), and seismic (for seismic prospecting) types. They are widely used for industrial blasting.