What is Racking?
Racking is an industry term used to describe the act of connecting or disconnecting a circuit breaker to electrical bus work inside of an electrical switchgear or cubicle. A withdrawable circuit breaker can be either racked to (i.e. moved) to a “connect” position or racked to a “disconnect” position.
While there are many different types of circuit breakers used across different voltage classifications, the primary function of racking is to physically disconnect the circuit breaker from the electrical switchgear so that no current flow can pass to an electrical load connected to the breaker. When racked to disconnect, a physical air gap will be created between the electrical buss work and circuit breakers so that the electrical circuit connected to the breaker may be worked on safely.
What is remote racking?
Remote racking is term used to describe a mechanical or electromechanical system that allows an operator to rack (move) a withdrawable circuit breaker from a connected position to a disconnected position or vice versa, from a remote location. Traditionally, racking a circuit breaker was performed by an operator by directly hand cranking or levering a circuit breaker onto or off of an electrical bus while standing in front of the circuit breaker.
Due to the high potential for an arc flash incident, remote racking systems were created to move the operator further away from the breaker when racking.
What does racking a circuit breaker mean?
Racking a circuit breaker is the act of physically moving a circuit breaker on to or off of an electrical bus, thereby physically connecting or disconnecting it from an electrical circuit. The circuit breaker may be moved vertically or horizontally usually by turning a hand cranked screw or a lever.
Who needs to rack a breaker?
Utility, Industrial, commercial and petrochemical company employees will need to rack circuit breakers in order to safely perform maintenance or repairs to electrical circuits. City power operators, mines, dams, shipping yards, and many others may need to have electrical circuits powered down so that a specific electrical circuit or the circuit breaker itself can be worked on safely. Only a certified and trained operators and technician should be racking circuit breakers.
What is a safe distance to be from a breaker when racking?
Safe working distances are required to be established by employers, owners and operators of the electrical equipment, based on the amount of available energy present at the breaker and the electrical system connected to it. Arc Flash Calculations are required to be performed in order to establish what these safe working distances and limits are for employees and contractors.
Some can be as little as three inches and as much as 150 feet. In the majority of cases, 40 to 50 feet away would be sufficient distance for an operator to remain from a breaker when it’s being racked, and not remain in direct line of sight. Our system allows for an operator to be up to 150 feet away from a breaker in those extreme cases.
Why Remote Racking?
Remote racking equipment keeps the operator of the equipment at a safe distance when the racking is in process. Distance is the best protection from the effects of an arc flash. Remote racking ensures that safe distances can be maintained throughout the racking process.
What is remote racking for?
Remote racking allows for an operator to safely connect or disconnect a circuit breaker from an electrical bus by increasing the operators distance away from the circuit breaker during the racking process.
What is local operation vs. remote of a circuit breaker?
Local operation of a circuit breaker means operating the circuit breaker while at the physical location of the circuit breaker. Local controls are physically located either on the switchgear cubicle door or on the circuit breaker. Remote operation of a circuit breaker means operating the breaker from a remote location not physically near the circuit breaker, like a control room or operations center.
How safe is remote racking?
When all safety procedures are strictly followed, including wearing proper PPE, and maintaining a safe distance from a circuit breaker when it’s being racked, nearly every workplace incident involving an arc flash injury due to breaker racking can be avoided.
What is an arc flash?
An arc flash is a discharge of light, heat, and sound energy that can occur in an electrical system when a short circuit is created within electrical equipment. When racking a circuit breaker into a position, an arc flash could occur due to a mechanical failure or misalignment inside of the equipment when it is being connected or disconnected from an electrical bus.
How does a circuit breaker cause an arc flash?
When racking a circuit breaker into a position, an arc flash could occur due to a mechanical failure or misalignment inside of the equipment when it is being connected or disconnected from an electrical bus.
Typical failures occur at the circuit breaker or switchgear primary disconnecting stabs or fingers when they are damaged or misaligned during connection or removal from the electrical bus. Other possible failures include an internal short circuit of the circuit breaker’s primary electrical insulation, mechanical failure, or the presence of foreign material causing a short circuit. Racking a circuit breaker when the breaker is internally closed will also cause an arc flash.