Abstract: In one aspect of the invention, an environmentally insensitive initiator, including: an electro-explosive device responsive to an electrical signal of unique voltage and frequency applied to the electro-explosive device, the unique voltage and frequency being such that are not otherwise present in a well completion operation. An example of voltage and frequency is 350V at 900 Hz. In another aspect, an initiator insertable in a housing insertable in a well casing, the initiator having a contact which is grounded when the initiator is uninstalled, to protect against unintended currents, but which becomes ungrounded by the act of inserting the initiator in the housing. In a further aspect, an initiator including a dual-function fuse.