When a circuit breaker is tripped in order to interrupt a short-circuit current, the
contact parting can start anywhere in the current loop. After the contacts have
parted mechanically, the current will flow between the contacts through an electric
arc, which consists of a core of extremely hot gas with a temperature of 5,000 to
20,000 K. This column of gas is fully ionized (plasma) and has an electrical conductivity comparable to that of carbon.