Instead of heating up the explosive, the EBW detonator wire is heated so quickly by the high firing current that the wire actually vaporizes and explodes due to electric resistance heating. That electrically driven explosion then fires the detonator's initiator explosive (usually PETN).

How does a detonator work?

Detonators are small devices used for detonating a high explosive. In a nuclear weapon, the nuclear part (called the core or the pit) is surrounded by high explosives. The detonation of those high explosives is what causes the pit to implode (compress) and create nuclear yield.

What is a detonator in explosive?

Detonators are devices used to initiate high explosives. A detonator is a complete explosive initiation device that includes the active part of the assembly (usually enclosed in a metal shell) and the attached initiation signal transmitter (for example, leg wires, a shock tube, or other signal-transmitting material).