Definition
An electrical circuit that has been verified to be fully de-energized, with no voltage present and no possibility of accidental energization while work is performed on it.
Plain English
A circuit that has been switched off and confirmed to have no power flowing through it, so it is safe to touch or work on.
Context Anchor
Seen in aircraft electrical-system maintenance and troubleshooting when checking whether a wire, switch, or component is powered.
Derivation
The term uses 'cold' in the electrical sense of 'without power,' the opposite of a 'hot' (live) circuit. The same hot/cold pairing is used widely in electrical and mechanical trades.
Why Pilots Care
Confirms the absence of power before any work begins, preventing shock or damage.
Analogy
It is like a lamp cord when the lamp is unplugged: the path exists, but electricity is not flowing through it.
Intuition Check
Cold does not mean low temperature here. It means the electrical path is not powered and no electricity is flowing through it.
Example Sentence 1
Before replacing the navigation light, the technician pulled the breaker and confirmed the circuit was cold.
Example Sentence 2
A cold circuit test is performed after pulling the circuit breaker.