A state in which the conductor or circuit part to be worked on or near has been disconnected from energized parts, locked/tagged in accordance with established standards, tested to ensure the absence of voltage, and grounded if determined necessary.
A device designed to produce sudden predetermined changes in one or more electrical circuits after the appearance of certain conditions in the controlling circuit.
A dangerous condition such that contact or equipment failure can result in electric shock, arc flash burn, thermal burn, or blast.
Intentionally connected conductors or electric equipment to earth, where the connection and conductors are of sufficiently low impedance to allow the conducting of an intended current.
The apparent opposition to current within a battery that manifests itself as a drop in battery voltage proportional to discharge current. Its value is dependent on battery design, state-of-charge, temperature and age.