Racking out moves a withdrawable breaker from the connected position, through test, to disconnected, pulling its primary contacts off the busbar and cable spouts and letting the shutters drop. It is the switchgear equivalent of opening a disconnector and is done only with the breaker already open. Racking is a high arc flash risk task, so remote racking devices and arc-rated clothing are common.
Breaker's open, rack it out to disconnected and padlock the shutters, then you can hang your tags.
Also heard as
- rack-out
- withdraw
- draw out
Related terms
Switchgear
Assemblies of breakers, switches, fuses, busbars and enclosures that control and protect power circuits.
Arc flash
Explosive release of heat, light and pressure when an electric arc forms through air between energised parts.
Tag out
To hang a danger tag on an isolation point so nobody operates it while people work downstream.
Switching order
Written step-by-step sequence of operations used to isolate or restore equipment safely.