what is the restricted approach boundary

The restricted approach boundary is a radius around live equipment that represents an increased risk of shock. The boundary restricts access to exposed and energized electrical equipment in the workplace. Safeopedia Explains Restricted Approach Boundary This is a concept defined by the National Fire Protection Association (NFPA

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Full Answer

What is the difference between limited approach boundary and restricted approach?

The limited approach boundary, restricted approach boundary and prohibited approach boundary classifications are based on the voltage of the energized equipment. But before a worker can approach exposed electric conductors or circuit parts that have not been placed in a safe work condition, a flash hazard assessment must be performed.

What is a prohibited approach boundary?

The prohibited approach boundary is the most high-risk of three approach boundaries used to delineate risk-level zones around electrical equipment. The two lower-risk approach boundaries are the restricted approach boundary and the limited approach boundary (lowest risk).

What is the limited approach boundary for electrical safety?

The Limited Approach Boundary is the distance from an exposed energized electrical conductor or circuit part within which a shock hazard exists. Again, this boundary is for shock and is not related to arc flash risk. It represents the approach limit for qualified employees which is 3’ 6” for voltage up 750V.

What are the different types of approach boundaries?

Approach Boundaries. There are two shock protection boundaries; the Limited Approach Boundary (LAB) and the Restricted Approach Boundary (RAB), and one Arc Flash Boundary (AFB) that must be established in order to provide a safe distance for personnel from exposed, energized electrical components.

What are the 3 limits of approach boundaries?

Under NFPA 70E, there are three boundaries that are observed—limited approach, restricted approach, (the shock protection boundaries) and arc flash boundary.

What is required to enter a restricted approach boundary?

Restricted approach boundary A person crossing this line enters into restricted space. Only qualified people may cross this boundary. Qualified people must have a written plan that is approved by authorized management. They must use PPE appropriate for working near energized parts.

What distance is the restricted approach boundary?

Limited Approach Boundary – The Limited Approach Boundary (LAB) is identified as the “distance from an exposed energized electrical conductor or circuit part within which a shock hazard exists”. Best practice if for any unqualified person to stay 42” (3' 6”) or more away from the hazard.

What is restricted approach boundary defined as in CSA z462?

The Restricted approach boundary is the distance between the source and the worker under which he or she must wear PPE against electric shock. At this distance, it is possible that the worker will also have to wear Arc Flash PPE.

Who can enter limited and restricted boundaries?

qualified personsNFPA 70 defines the limited approach boundary as a shock protection boundary to be crossed by only qualified persons (at a distance from a live part), which is not to be crossed by unqualified persons unless escorted by a qualified person.

Who can cross the limited approach boundary?

qualified personsThe Restricted Approach Boundary (RAB) is the approach limit for qualified persons to exposed, energized electrical components where there is an increased likelihood of electric shock due to electrical arc-over combined with inadvertent movement. Only qualified persons may cross this boundary.

How does the NFPA 70e standard define a limited approach boundary?

NFPA 70e® defines the limited approach boundary (also known as the flash protection boundary) as the farthest point at which a shock hazard exists. Should an arc flash occur, people in the limited approach boundary would be exposed to curable second degree burns of 1.2 calories/cm2.

What is the arc flash boundary for 480v?

12 inchesThe earlier mentioned voltages of 208, 220, 240, 277, 380, and 480 volts AC have a restricted boundary of 12 inches.

Can an unqualified person enter the limited approach boundary?

They should not cross into the arc flash boundary unless they are wearing appropriate PPE and are supervised by a qualified person. At no time should an unqualified person enter the restricted approach boundary.

What is the purpose of the CSA Z462 standard?

This Standard specifies requirements for and provides guidance on safety management systems, safe work procedures, and selection of personal protective equipment and other safety devices for persons exposed to hazards associated with energized electrical equipment.

What is the definition of a shock hazard according to CSA Z462?

An “arc flash hazard” is defined by the CSA Z462-15 Workplace Electrical Safety as a “dangerous condition associated with the release of energy caused by an electric arc”.

What is the most restricted method in the hierarchy?

The hierarchy goes from the most-effective to the least-effective control methods. Elimination is ranked first, and PPE is ranked last. The term “hazard analysis” was an integral component of past editions of NFPA 70E, but it has been replaced in 2015 with “risk assessment.”

What Does Prohibited Approach Boundary (PAB) Mean?

The prohibited approach boundary (PAB) is the distance away from a piece of energized electrical equipment. The distance of the boundary is determined by the amount of voltage running through the equipment.

What is the most high risk approach boundary?

The prohibited approach bound ary is the most high-risk of three approach boundaries used to delineate risk-level zones around electrical equipment. The two lower-risk approach boundaries are the restricted approach boundary and the limited approach boundary (lowest risk).

Is crossing a prohibited approach boundary the same as making physical contact with a live part of the equipment?

For safety purposes, crossing a prohibited approach boundary is considered the same as making physical contact with a live part of the equipment due to the elevated risk level faced by workers within this boundary .

What is the purpose of the arc flash boundary limits?

To lower the risk of arc flash injuries, the National Fire Protection Association® developed a set of arc flash boundary limits to guide decisions on both equipment operation and personal protective equipment.

How to work within an arc flash boundary?

To be qualified to work within arc flash boundaries an employee must have proper electrical safety training, be able to demonstrate the skills needed for safely operating equipment, and an understanding of the hazards involved. Additionally, an employee who has received on-the-job training and has the ability to perform such duties safely may work within the limited approach boundary under the direct supervision of qualified personnel.

Can you work within the restricted approach boundary?

The closer an employee is to exposed electrical components the greater the risk of serious arc flash injuries. Only qualified individuals with energized electrical work permits can work within the restricted approach boundary.

Can an unqualified person enter a boundary?

An unqualified person wearing appropriate PPE can also enter the boundary, but only if escorted at all times by a qualified individual, and then only if informed of arc flash hazards . The closer an employee is to exposed electrical components the greater the risk of serious arc flash injuries.

What is the boundary of a shock?

The outer boundary at which a worker may be exposed to a shock hazard, the limited approach boundary, refers to the “stay back” distance for non-qualified workers. Qualified workers may cross this boundary after shock and arc flash risk assessments are performed with appropriate PPE if needed.

What is the arc flash boundary?

While the other two boundaries deal with shock hazard, the arc flash boundary refers specifically to arc flash hazards and explains that 1.2 calories/cm 2 of incident energy, is the distance at which a worker will receive second-degree burns in the event of an arc flash incident without appropriate arc rated personal protective equipment.

What are the boundaries of NFPA 70E?

Under NFPA 70E, there are three boundaries that are observed—limited approach, restricted approach, (the shock protection boundaries) and arc flash boundary . These boundaries trigger multiple requirements in 70E including but not limited to determining the type and level of PPE and qualifications required to cross into each level. As part of a larger training and safety program, these boundaries are put in place to minimize risk through avoidance or the use of PPE.

What is the hierarchy of controls in electrical safety?

NFPA 70E (2018) highlighted the Hierarchy of Controls, a systematic way of reducing hazards and risk. This hierarchy starts at the source (elimination) and moves into more plausible methods of risk mitigation.

Should you stay outside the boundary?

Workers without specialized training should stay outside of the boundary unless they have appropriate protection and are escorted by a qualified person.

What is a restricted approach boundary?

The Restricted Approach Boundary (RAB) is the approach limit for qualified persons to exposed, energized electrical components where there is an increased likelihood of electric shock due to electrical arc-over combined with inadvertent movement. Only qualified persons may cross this boundary. A qualified person required to cross the RAB must be protected from unexpected contact with exposed energized conductors or circuit parts. Working within the RAB is only acceptable if an Energized Electrical Work Assessment has been completed and approved, or if the work is specifically exempt per NFPA 70E-2021 130.2 (B) (3).

What is a LAB boundary?

The Limited Approach Boundary (LAB) is the approach distance to exposed, energized electrical components within which a shock hazard exists. It is the approach limit for unqualified persons. Unqualified persons may only cross this boundary if they are under the direct supervision of a qualified person, and wearing the appropriate personal protective equipment for the hazards involved. Working within the LAB is only acceptable if an Energized Electrical Work Assessment has been completed and approved, or if the work is specifically exempt per NFPA 70E-2021 130.2 (B) (3).

What is the boundary of shock protection?

There are two shock protection boundaries; the Limited Approach Boundary (LAB) and the Restricted Approach Boundary (RAB), and one Arc Flash Boundary (AFB) that must be established in order to provide a safe distance for personnel from exposed, energized electrical components.

What is the AFB?

The Arc Flash Boundary (AFB) is the distance from exposed, energized electrical components within which a person could receive a second degree burn if an electrical arc flash were to occur. The AFB is determined either through calculation or through the use of the following tables. Personnel must be wearing the appropriate arc-rated protective equipment before crossing this boundary. Arc-rating is reported as either the Arc Thermal Performance Value (ATPV) or the Energy of Break-open Threshold (EBT).

What is a limited approach boundary?

The limited approach boundary is defined by the NFPA 70E as, “An approach limit at a distance from an exposed energized electrical conductor or circuit part within which a shock hazard exists.” We often call this the “common sense boundary” meaning that no worker should be within a certain limit when there is exposed electrical energy.

What is an arc flash boundary?

The arc flash boundary is defined by the NFPA 70E as, “When an arc flash hazard exists, an approach limit from an arc source at which incident energy equals 1.2 cal/cm 2 (5 J/cm 2 ).” According to the Stoll skin burn injury model, this is where a worker could potentially receive a second-degree burn if exposed for one second.

What is a limited approach boundary?

Limited Approach Boundary– The Limited Approach Boundary (LAB) is identified as the “distance from an exposed energized electrical conductor or circuit part within which a shock hazard exists”. Best practice if for any unqualified person to stay 42” (3’ 6”) or more away from the hazard. A qualified person should use protective shields and barriers to protect employees working within the LAB. Barriers should be used to help unqualified persons recognize a hazard is present and keep them from entering the LAB without being escorted by a qualified person.

How does elimination of risk help with electrical hazards?

The elimination of risk will help to prevent injury or bodily harm cause by electrical shock and arc flash incidents.

How far away from a hazard is LAB?

The LAB and RAB vary depending on voltage present. Best practice is to keep any unqualified person 10’ or more away from the hazard. Please see the chart below to determine these distances for the above identified voltages and greater: