High energy electrical systems have the potential to cause serious injury with shock and flash hazards and significant equipment damage. During racking, stabbing, and switching of high energy electrical systems, the potential hazards are greater than at other times. This guideline defines safety considerations and requirements to minimize the risk to personnel performing these tasks.
Racking is the operation of engaging or disengaging an electrical starter/breaker onto or off its feeder bus. This type of equipment usually consists of a gear system with a hand or motor operated crank (racking mechanism).
Stabbing is the removal or insertion of a plug-in starter into or out of a motor control center (by hand, no racking mechanism).
Switching is the operation of an electrical switch to energize or de-energize a portion of the electrical system.
High energy electrical systems are defined as systems which have the potential to cause arc flash burns. All power circuits operating above 400 volts are considered high energy. In addition, other equipment (operating below 400 volts) identified through an engineering analysis may be considered high energy. Arc flash PPE is required for performing tasks involving high energy systems. High energy equipment must be identified and labeled with specific arc flash PPE requirements.
- Personnel must be trained to perform racking, stabbing and switching tasks and to recognize the hazards that are present when performing this type of work. Instrument and Electrical personnel with electrical skills are authorized to perform the tasks described in this guideline.
- Personnel should understand and demonstrate proper body position when performing switching operations and understand arc flash PPE requirements and demonstrate proper use of arc flash PPE.
- Receive hands-on instruction on the specific task being performed from an individual who is authorized and experienced in performing that task.
- A standby person is recommended for the following tasks:
- Racking and switching of any energized system operating above 1000 volts.
- Racking of substation breakers in an energized substation.
- Stabbing involving an energized motor control center (MCC).
- Any electrical work that requires a “Permit for Electrical Work On or Near Energized Circuits.”
- Stabbing involving an energized MCC should be performed only by an Instrument and Electrical personnel with electrical skills.
- Personnel performing racking, stabbing and switching tasks must wear PPE to ensure that anyone within the arc flash boundary is properly protected.
- Guidance for racking and switching
- Obtain work permit from Operations for the task to be performed, if required. Communicate to the affected group, area or personnel what equipment will be effected by the switching task.
- Determine potential hazards and the best body position for the task which is to be performed.
- If breaker or switch is new or had been removed for maintenance, verify that the equipment was inspected and tested before installation by Instrument and Electrical personnel.
- If a breaker is to be racked in or out, verify that it is in the open position before racking.
- Ensure proper PPE is used for the task to be performed.
- Follow all related operation area mechanical procedures and/or labeling instructions.