What Does Restricted Approach Boundary (RAB) Mean?
The restricted approach boundary (RAB) is a radius around live electrical equipment that represents an increased risk of electric shock and arc flashes.
It is one of three hazardous area boundaries defined by the NFPA's 70E Standard for Electrical Safety in the Workplace and stands between the the limited approach boundary and the prohibited approach boundary.
Safeopedia Explains Restricted Approach Boundary (RAB)
The prohibited approach boundary (PAB) delineates the area closest to the equipment. Crossing it places a worker at a risk similar to coming into contact with the live part. Only those with specialized training are allowed to cross this boundary, and only with adequate arc flash PPE and a documented plan approved by the authorized management.
The restricted approach boundary sits outside the PAB. It should only be crossed by qualified persons with the training and PPE required to work safely where arc flash hazards are present.
Outside the RAB is the limited approach boundary (LAB). This area can be accessed by employees who are not qualified persons. However, there is a risk of electric shock in the LAB and workers must take all the necessary precautions when entering the LAB.
The precise location of each boundary is calculated based on the voltage range of the electrical equipment.