- Responsibilities required under this policy
- De-energizing electrical equipment
- Safe operating procedures using boundaries, barriers, and PPE
- Safe operating procedures for energized diagnostic work
- Safe operating procedures for energized repair work
- Completing the Energized Work Permit (Mandatory Appendix D)
- Electrical safety training
3.0 Definitions
The following terms are defined to allow a better understanding of this program. For more detailed definitions, refer to 2018 NFPA 70E, Article 100.
Arc Flash Risk Assessment:
An arc flash risk assessment is a process to determine if an arc flash hazard exists. If it does, the risk assessment shall determine the appropriate safety-related work practices, the arc flash boundary, and the personal protective equipment (PPE) to be used within the arc flash boundary.
Arc Flash Suit:
A complete AR (Arc-Rated) clothing and equipment system that covers the entire body, except for the hands and feet.
Apparel is a broad category of clothing designed to protect employees from electrical arc events during completion of energized tasks. (Such a suit typically includes pants, jacket, and a “beekeeper” style hood fitted with a face shield). (see NFPA 70E 130.7(C))
Note: Protective apparel for other body parts, including hands, feet, and hearing is also required. [See Section 7.0], “Electrical Personal Protective Equipment.”
Arc Rating:
The maximum incident energy resistance demonstrated by a material (or a layered system of materials) prior to “breaking open” or at the onset of a second-degree skin burn. This rating is assigned to electrical protective clothing and is normally expressed in calories per square centimeter (cal/cm2).
Note: An arc rating indicates the clothing or equipment has been tested for protection against exposure to an electric arc. Flame resistant clothing, without an arc rating, has not been tested for exposure to an electric arc. (see 2018 NFPA 70E-100)
Boundary:
A distance from an electrical device or system used to specify what activities are allowed, and what personal protective equipment is required within that distance from the electrical device or system.
There are two boundary categories: the arc flash boundary and the shock protection boundaries. There are two levels of shock protection boundaries: limited approach boundary and restricted approach boundary.
Boundary, Arc Flash:
Distance from exposed live parts within which a person could receive a second-degree burn if an electrical arc flash were to occur. This boundary may only be crossed by a qualified person wearing the appropriate personal protective equipment (PPE).
Boundary, Shock Protection:
The shock protection boundaries identified as limited approach boundary and restricted approach boundary shall be applicable where approaching personnel are exposed to energized electrical conductors or circuit parts.
Boundary, Limited Approach:
The distance from an exposed energized electrical conductor or circuit part within which a shock hazard exists.
Boundary, Restricted Approach:
The distance from an exposed energized electrical conductor or circuit part within which there is an increased likelihood of electric shock, due to electrical arc-over combined with inadvertent movement, for personnel working in close proximity to the energized electrical conductor or circuit part.
De-energized:
(De-energized): Free from any electrical connection to a source of potential difference and from electrical charge; not having a potential different from that of the earth.
Electrically Safe Work Condition:
A state in which an electrical conductor or circuit part has been disconnected from energized parts, locked/tagged in accordance with NCSU policy, tested to ensure the absence of voltage, and grounded if determined necessary.
Energized:
Electrically connected to, or is, a source of voltage.
Exposed (as applied to energized electrical conductors or circuit parts):
Capable of being inadvertently touched or approached nearer than a safe distance by a person. It is applied to electrical conductors or circuit parts that are not suitably guarded, isolated, or insulated.
Hazard:
A source of possible injury or damage to health.
Hazardous:
Involving exposure to at least one hazard.
Incident Energy:
The amount of thermal energy impressed on a surface, a certain distance from the source, generated during an electrical arc event. Incident energy is typically expressed in calories per square centimeter (cal/cm2) at a specified distance.
Live Parts:
Energized conductive components.
Maintenance:
Activities which promote the operation or extend the life of equipment or systems.
PPE:
An acronym for “Personal Protective Equipment”.
Qualified Person:
One who has demonstrated the skills and knowledge related to the construction and operation of electrical equipment and installations and has received safety training to identify and avoid the hazards involved. [See Section 5.0] Training
Unqualified Person:
A person who is not a qualified person. A person who has not received safety training or who has not demonstrated the skills and knowledge related to the construction and operation of electrical equipment and installations.
Working Distance:
The distance from the source/origin of a potential arc flash and the plane defined by the employee’s face and chest. Note: The working distance as defined by the table method is fixed, whereas it can vary when the incident energy method is employed [Section 8.2] Arc Flash Risk Assessment Methodology .
Working Near (energized electrical conductors or circuit parts):
Any activity within a limited approach boundary.
Working On (energized electrical conductors or circuit parts):
Intentionally coming in contact with energized electrical conductors or circuit parts with the hands, feet, or other body parts, with tools, probes, or with test equipment, regardless of the personal protective equipment (PPE) a person is wearing.
There are two categories of “working on”:
Diagnostic (testing) is taking readings or measurements of electrical equipment with approved test equipment that does not require making any physical change to the equipment.
Repair is any physical alteration of electrical equipment (such as making or tightening connections, removing or replacing components, etc.).
4.0 Approach Boundaries to Live Parts
Observing a safe approach distance from exposed energized parts is an effective means of maintaining electrical safety. As the distance between an individual and live parts increases, the potential for an electrical injury decreases. Safe approach distances will be determined for all tasks in which approaching personnel are exposed to live parts. For shock hazards, safe approach distances to fixed live parts can be determined by referring to mandatory Appendix A, “Shock Protection Approach Boundaries.” This appendix must be used to identify the limited and restricted approach boundaries associated with various system voltages.
The arc flash boundary is determined by an Arc Flash Risk Assessment and is based on several system attributes in addition to voltage. Refer to Section 4.3 and Section 8.0, below.
Barricades shall be used in conjunction with safety signs, where necessary, to prevent or limit employee access to work areas containing energized conductors or circuit parts. Conductive barricades shall not be used where it might increase the likelihood of exposure to an electrical hazard. Barricades shall be placed no closer than the applicable limited approach boundary given in Appendix A, (ref. 2018 NFPA 70E Table 130.4 (D)(a) or Table 130.4(D)(b)). Where the arc flash boundary is different than the limited approach boundary, barricades shall be placed at the farther boundary.
4.1 Limited Approach Boundary
No unqualified person shall be permitted to approach nearer than the limited approach boundary of energized conductors and circuit parts unless a qualified person advises him or her of the possible hazards and continuously escorts the unqualified person while inside the limited approach boundary. Where one or more unqualified persons are working at or close to the limited approach boundary, the person in charge of the workspace where the electrical hazard exists shall advise the unqualified persons of the electrical hazards and warn him or her to stay outside of the limited approach boundary.
4.2 Restricted Approach Boundary
Qualified persons shall not approach or take any conductive object closer to exposed energized electrical conductors or circuit parts operating at 50 volts or more into the restricted approach boundary unless one of the following conditions apply:
- The qualified person is insulated or guarded from contact with the live parts operating at 50 volts or more. No uninsulated part of the qualified person’s body should cross the restricted approach boundary; or
- The live parts operating at 50 volts or more are insulated from the qualified person and from any other conductive object at a different potential; or
- The qualified person:
- has evaluated the task and is qualified to perform the work, and
- has taken the proper safety precautions, including use of PPE appropriate for working on the energized parts, as determined during the risk assessment, and
- has filled out the applicable energized work permit (EWP) by
- providing justification that deenergization creates a greater hazard than working energized, and
- has obtained written management approval to proceed
Note: An EWP is not required for troubleshooting, testing, voltage measurement, or visual observation.
Under no circumstance shall an unqualified person be permitted to cross the restricted approach boundary.
4.3 Arc Flash Boundary
The arc flash boundary is the distance from exposed live parts within which a person could receive a second-degree burn (1.2 cal/cm 2 ) if an electrical arc flash were to occur. This boundary may only be crossed by a qualified person wearing the appropriate personal protective equipment (PPE).
To determine the arc flash boundary, an Arc Flash Risk Assessment [Section 8.0] must be done, using the Incident Energy (IE) Analysis Method. If the equipment has not had an IE analysis, the user should contact EHS for assistance, env-health-occ-safety@ncsu.edu, 919-515-6655.
The arc flash boundary may also be determined using the “Table Method;” provided the following requirements are met:
- The equipment must be defined in one of these mandatory appendices:
- Appendix B, “Arc Flash Boundary Chart for AC Systems,” or
- Appendix C, “Arc Flash Boundary Chart for DC Systems,” and
5.0 Training (derived from 2018 NFPA 70E, 110.2)
5.1 Employees exposed to an electrical hazard must receive electrical safety training based on the level of the hazard and dependent on the work being done. A qualified person will receive more training than an unqualified person.
Note: A person can be considered qualified with respect to certain equipment and tasks but not qualified for other equipment or tasks.
5.2 All employees exposed to actual or potential electrical hazards are required to have training to include:
- Basic electrical safety.
- Contact Release.
- Electrical Personal Protective Equipment: selection, use, limitations, donning, doffing, & maintenance.
- Lockout/Tagout-Control of Hazardous Energy for authorized employees, to include equipment specific energy control procedures for applicable equipment.
- Proper use of an electrical multi-meter
- Arc flash hazard awareness.
- First Aid, Emergency Response, cardiopulmonary resuscitation (CPR) and automated external defibrillator (AED). Knowledge and skills shall be updated through additional or refresher training according to the requirements of the certifying body. Note: These courses are required for employees working on power distribution systems. They are recommended for all employees working with electrical equipment.
- “Electrical Safety for the Mechanical Trades” is recommended for all employees working with electrical equipment with operating voltage greater than 50 V.
5.3 Only qualified persons are authorized to perform energized work.
- A qualified person is one who has demonstrated the skills and knowledge in all of the following topics:
- Understands the construction and operation of equipment on which work is assigned or for a specific work task. The person shall be trained to identify and avoid the electrical hazards that might be present with respect to that equipment or work task.
- Understands the proper use of the precautionary techniques, applicable electrical policies and procedures, PPE, insulating and shielding materials, and insulated tools and test equipment.
- Demonstrates the skills and knowledge necessary to distinguish exposed energized parts from other parts of electrical equipment.
- Demonstrates the skills and knowledge necessary to determine the nominal voltage of exposed live parts.
- Demonstrates knowledge of the approach distances specified in this document and the corresponding voltages to which the qualified employee will be exposed.
- Demonstrates knowledge of the process necessary to determine the degree and extent of electrical hazards, to assess the risk, to select the proper PPE, and to demonstrate appropriate job planning necessary to perform the task safely.
6.0 Responsibilities
6.1 All Departments conducting electrical work
- Take appropriate action to implement the provisions of this policy, including maintaining Department specific procedures as needed for required elements. These may include:
- Determining training and experience requirements for qualified persons,
- Determining on-call or after hours work procedures
- Determining PPE and clothing or uniform requirements applicable to the hazard. For example, if most exposures are below 11 cal/cm 2 , an 11 cal coverall may be more appropriate than a 40 cal suit.
6.2 Departments responsible for operating and maintaining electrical equipment
(For Example: Building Maintenance and Operations in Facilities Division and Facilities units in DASA, Athletics, and Campus Enterprises)- Provide secondary three phase short circuit current (SCC) information for all NCSU main building transformers for inclusion in the designated maintenance database (such as AiM). Include transformer name plate information and the overcurrent protection device(s) specifications. This information shall be provided to allow an incident energy analysis to be performed on equipment and facilities served by the department.
- Determine the potential arc flash hazard for all equipment operated and maintained by the Department.
- Provide labels for equipment with the information required for safe operations.
- Produce and maintain one-line diagrams for every building electrical system. The one-line diagrams shall provide the available short circuit current at each piece of equipment and the overcurrent device type, size, and settings. (ref 2018 NFPA 70E 205.2)
6.3 Supervisors, Superintendents, PIs, Managers
- Implement the electrical safety program requirements within their areas.
- As appropriate, establish themselves as qualified by completing the required training or demonstrating appropriate experience or knowledge.
- Verify employees comply with all provisions of the Electrical Safety Program.
- Ensure employees receive training appropriate to their assigned electrical tasks and maintain documentation of such training.
- Develop and maintain a listing of all qualified employees in their areas.
- Ensure training is updated every 3 years. (ref 2018 NFPA 70E 110.2(A)(3))
- Ensure employees are provided and properly use and maintain appropriate personal protective equipment.
- Ensure preliminary electrical safety training for all new employees as outlined in the Manager’s Safety Orientation Checklist.
- If energized electrical work needs to be performed, ensure employees use the Energized Work Permit as specified in this policy.
6.4 Employees
- Follow the work practices described in this policy including the use of appropriate personal protective equipment and tools, and proper hazardous energy control or Lockout/Tagout procedures.
- Complete all required training relative to this program.
- Use the Energized Work Permit as specified in this policy.
- Report any concerns related to electrical safety to their supervisor.
6.5 Contract Employers
- NCSU Responsibilities NCSU shall inform contract employers of the following:
- Known hazards that are related to the contract employer’s work, and that might not be recognized by the contract employer or its employees.
- Information about NCSU’s installation(s) or equipment that the contract employer needs to make their own risk assessment.
- NCSU shall ensure that all contractors are required to comply with NCSU electrical safety requirements.
- Any unique hazards presented by the contract employer activities.
- Hazards identified during the course of work by the contract employer that were not communicated by NCSU.
7.0 Electrical Personal Protective Equipment
7.1 Electrical PPE requirements are described in a separate program titled “Electrical Personal Protective Equipment” and shall be followed by all NCSU employees. Contact EHS Occupational Safety, Env-Health-Occ-Safety@ncsu.edu, 919-515-6655, for assistance.
8.0 Arc Flash Risk Assessment
8.1 Overview The 2018 edition of NFPA 70E requires analysis of incident energy or arc flash PPE category for determination of arc flash hazards, and specifies the following:
- The appropriate safety-related work practices.
- The arc flash boundary and limited and restricted approach boundaries.
- The PPE to be used within the arc flash boundary.
8.2 Arc Flash Risk Assessment Methodology There are two methods for determining the approach distances (arc flash boundary) and the arc rated PPE required for energized work: the Incident Energy (IE) Analysis Method and the Arc Flash Categories Method (Table Method). The IE method is preferred. The two methods shall not be combined.
- Incident Energy Analysis Method. This method is based on detailed calculations, often with the aid of specialized software, to determine the maximum potential incident energy exposure in calories per square centimeter (cal/cm 2 ). Once the incident energy exposure is calculated, the required arc flash boundary can be determined and the appropriate arc rated protective clothing can be specified according to Annex H, table H.3(b) in NFPA 70E. The Incident Energy Analysis method must be used if the Table Method cannot be utilized. It may be used to determine more accurate results than is available with the Table Method.
- Table Method. This method is used by looking up specific equipment types in a table: mandatory Appendix B, for AC systems; or mandatory Appendix C, for DC systems. The Table Method may only be used by a person qualified on the equipment to be worked on.
The equipment to be worked on must exactly match the equipment described in the table. Based upon the short-circuit current available and the fault clearing time, the required arc flash PPE category and the arc-flash boundary are then read from the table. If all parameters in the table are not met, this method shall not be used and therefore, the Incident Energy Analysis method is required. Contact EHS Occupational Safety, Env-Health-Occ-Safety@ncsu.edu, 919-515-6655, if there are questions.
The table method can be inaccurate and, while generally conservative, the maximum potential energy of some equipment may be greater than the PPE category determined by the table. The Incident Energy Analysis Method is preferred.
9.0 Operating Procedures – Energized Work
9.1 Appendix E, “Electrical Work Decision Flow Chart” can be used as guidance for doing safe electrical work.
9.2 Energized parts to which an employee may be exposed shall be de-energized before the employee works on or near them.
9.3 At no time shall any employee perform work alone on energized equipment. Only employees qualified for the task may work on or near energized equipment.
9.4 Energized parts that operate at less than 50 volts to ground need not be de-energized if there will be no increased exposure to electrical shock or burns or to explosion due to electric arcs.
9.5 Some diagnostic work must be done energized. Every effort should be made, where possible, to work without coming in physical contact with electrical conductors or circuit parts. Refer to Section 9.7(A) for information on energized diagnostic work.
9.6 Repair work must be done de-energized unless the qualified person can justify working energized using one or more of the criteria specified in Section 10.0. Where the qualified person is closer than the arc flash or restricted approach boundary, An energized work permit, Section 11.0, must be used. An energized work permit is not required for repair work done remotely.
9.7 Working On or Near Energized Parts (refer to definition in Section 3.0, above)
- Energized Diagnostic work, which includes only testing, troubleshooting, voltage or current measurement and visual inspection may be done without an energized work permit provided ALL the following apply:
- An arc flash hazard assessment has been done to determine approach boundaries and PPE.
- Appropriate safe work practices and PPE are used;
- The work has been approved by area or Department supervisor(s);
- Only meter probes are allowed near electrical equipment for this type of activity.
- Tools other than meter probes are not allowed within the working distance, restricted approach boundary, or arc flash boundary.
9.8 On-Call or After Hours Operations involving energized work.
- Diagnostic energized work: The qualified person working after hours will do energized diagnostic work as specified in the Section 9.7(A).
- Repair work: For repairs, the qualified person working after hours shall complete the Energized Work Permit and secure appropriate written approvals as specified in Section 11.0, for repairs or for work on energized battery systems. The qualified person shall do the energized repair work as specified in Section 9.7(B).
- The qualified person performing other energized work after hours shall complete the Energized Work Permit and secure appropriate written approval as specified in Section 11.0, The qualified person shall do the energized repair work as specified in Section 9.7(C).
10.0 Justification for energized electrical work:
10.1 Only these criteria may be used to justify doing energized repair work.
- De-energization creates additional or increased hazards than not deenergizing.
Examples are:- Interruption of life support systems, or
- Deactivation of emergency systems that cannot be rectified by other means such as a fire watch, manual monitoring, or bypass, or
- Shutdown of hazardous location ventilation where shutdown will create additional or increased hazards and it is impossible to mitigate the hazard prior to de-energization.
- Diagnostic work which must be conducted as part of a repair
Note 1: Only the diagnostic portion of the work may be done energized. The repair part of the work must still be done de-energized, even if the qualified person switches back and forth between diagnostic work (energized) and repair work (de-energized). - Circuits to be repaired are an integral part of a continuous industrial process that would otherwise need to be completely shut down.
Note 2: It is only infeasible if the orderly shutdown of related equipment and processes would introduce additional or increased hazards. (ref: OSHA Letter of Interpretation: 12/19/2006 – “Continuous industrial processes” and the infeasibility of de-energizing equipment under 29 CFR 1910.333). - Work on energized circuits of Battery Backup Systems, which cannot be de-energized.
11.0 Energized Electrical Work Permit (EEWP/EWP), mandatory Appendix D
11.1 Determine the arc flash hazard (See Section 8.0).
11.2 Determine the justification for conducting work energized (See Section 10.0).
11.3 Obtain management approval to proceed.
11.4 Establish approach and arc flash boundaries, according to 2018 NFPA 70E.
11.5 Erect barricades and signage to prevent personnel from entering the area of the hazard.
11.6 Use insulated tools and equipment.
11.7 Use insulated mats when required.
11.8 Determine and wear the required PPE.
11.9 Wear safety glasses and hearing protection.
11.10 Wear electrical shock protective PPE, including, but not necessarily limited to, voltage rated gloves, safety glasses, ear insert hearing protectors, EH rated hard-soled leather work shoes.
11.11 Wear appropriate AR upper and lower body personal protective equipment (Mandatory Appendix B or Appendix C, and 2018 NFPA 70E Annex H).
11.12 The permit is to be originated by the individual requesting the energized work. (This may be the qualified technician responsible for the operation and maintenance of the building systems, a supervisor, or a project manager.)
11.13 All Energized Electrical Work Permits shall be submitted to the appropriate supervisor for approval.
- The permit must be signed by the Department or Division Director or authorized delegate, the approving supervisor, the qualified person conducting the risk assessment, and all persons exposed to the hazard.
- Signatures indicate understanding of, and agreement with, and of the information submitted on the permit.
11.14 The permit must be posted in the area where the energized work is taking place for the duration of the task.
11.15 Energized Electrical Work Permits must be kept (with a copy of the work order(s), as appropriate) on file by the supervisor upon completion of the task. Permits shall be kept for a minimum of three years in order to be used as part of the audit process.
11.16 A copy of the NCSU Energized Electrical Work Permit can be found in mandatory Appendix D of this Policy. The intent of this permit is to ensure that all appropriate safety precautions are taken prior to starting energized electrical work and to ensure oversight by supervisors in the area the work is being performed.
12.0 Appendix E, the “Electrical Work Decision Flow Chart” can be used as guidance for doing safe electrical work.
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- Energized Diagnostic work, which includes only testing, troubleshooting, voltage or current measurement and visual inspection may be done without an energized work permit provided ALL the following apply:
- NCSU Responsibilities NCSU shall inform contract employers of the following:
- Take appropriate action to implement the provisions of this policy, including maintaining Department specific procedures as needed for required elements. These may include:
- A qualified person is one who has demonstrated the skills and knowledge in all of the following topics:
- The equipment must be defined in one of these mandatory appendices: