Introduction

This guidance document provides guidelines on selection of Personal Protective Equipment (PPE) for protection from electric arc flash from equipment for which detailed arc hazard analysis has not been performed. This guidance applies to situations in which staff may be exposed to arc flash from high voltage switches or live unguarded electrical wires, parts, or equipment with voltages above 50 Volts. PPE is not required when working in proximity to electrical equipment in enclosed panels with no exposed connectors, where electrical work is not being performed and where no high voltage switch is being operated.

An arc flash may occur when electrical current “short circuits,” that is, flows from energized wires or equipment to ground, or between energized wires or equipment with different phases or potential. An arc flash may also occur during movement of energized electrical contactors, such as switches. The arc flash creates electrically conductive superheated plasma that can reach temperatures of 5000° F and above. Occurring in a fraction of a second, it produces a brilliant flash, intense heat, and a shock wave. The magnitude of the energy and other factors will determine the severity of the arc flash.

This guidance is derived from the National Fire Protection Association’s (NFPA) NFPA 70E, Standard for Electrical Safety in the Workplace. This document will summarize key provisions of NFPA 70E as they apply to work conducted by WSU employees. Refer to NFPA 70E for additional information. This guidance should be used unless there is a detailed arc hazard analysis and Hazard Mitigation Plan that has calculated arc flash energy and established PPE requirements for the specific equipment being worked on. Those pieces of equipment which have undergone a detailed arc flash analysis shall be labeled with a label such as that pictured below. You must follow the specifications on those labels.

 

 

  1. PURPOSE

This program serves the purpose to ensure the safety of employees who may work on or near electrical systems. That qualified employees understand how to comply with safety standards related to electrical safety and follow uniform practices during the completion of electrical work.

  1. Definitions

Arc Rating [NFPA 70E]: The maximum incident energy resistance demonstrated by a material (or a layered system of materials) prior to break open or at the onset of a second-degree skin burn. Arc rating is normally expressed in cal/cm2.

Boundaries:

Limited Approach Boundary: 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". The limited approach boundary is the minimum distance from the energized item where unqualified personnel may safely stand. No untrained personnel may approach any closer to the energized item than this boundary... See Tables 1a and 1b in this document.

Restricted Approach Boundary: A shock protection boundary to be crossed by only qualified persons (at a distance from a live part) which, due to its proximity to a shock hazard, requires the use of shock protection techniques and equipment when crossed. To cross the Restricted Approach Boundary into the Restricted Space, the qualified person, who has completed required training, must wear appropriate personal protective equipment (PPE). Also, he must plan the work to keep all parts of the body out of the Prohibited Space. See Tables 1a and 1b in this document.

Prohibited Approach Boundary: A shock protection boundary to be crossed by only qualified persons (at a distance from a live part) which, when crossed by a body part or object, requires the same protection as if direct contact is made with a live part. Only qualified personnel wearing appropriate personal protective equipment (PPE), having specified training to work on energized conductors or components, and a documented plan justifying the need to perform this work may cross the boundary and enter the Prohibited Space. See Tables 1a and 1b in this document.

Circuit Breaker [NFPA 70E]: A device designed to open and close a circuit by non-automatic means and to open the circuit automatically when a predetermined over current occurs without damage to itself when properly applied within its rating.

Dead Front [NFPA 70E]: Without live parts exposed to a person on the operating side of the equipment.

Disconnecting Means [NFPA 70E]: A device, or group of devices, or other means by which the conductors of a circuit can be disconnected from their source of supply.

Electrical Glove Class (as specified on Arc Flash Labels): Electrical protective gloves are categorized by the level of voltage protection provided, which are rated by Class. Ozone resistance is noted by Type. Type I gloves are not ozone resistant. Type II gloves are resistant to ozone.

 

  • Class 00 – 500 Volts Maximum
  • Class 0 – 1,000 Volts Maximum
  • Class 1 - 7,500 Volts Maximum
  • Class 2 – 17,000 Volts Maximum
  • Class 3 – 26.500 Volts Maximum
  • Class 4 – 36,000 Volts Maximum

 

 

Electrical Hazard [NFPA 70E] – A dangerous condition such that contact, or equipment failure can result in electric shock, arc flash burn, thermal burn, or blast.

 

Entry into the Flash Protection Boundary: occurs when the face, head or trunk of the person crosses the boundary. Within this boundary workers are required to wear appropriate PPE. [Note: if hands cross the boundary, PPE is required on the hands and arms]

 

Exposed (as applied to live parts) [NFPA 70E]: Capable of being inadvertently touched or approached nearer than a safe distance by a person. It is applied to parts that are not suitably guarded, isolated, or insulated.

 

Exposed (to arc flash hazard): Within the flash protection boundary during work activities on or close to unguarded energized electric wires or equipment, or activation of unguarded energized electrical switches. This includes opening of electrical enclosures.

 

Flash Hazard [NFPA 70E]: A dangerous condition associated with the release of energy caused by an electric arc.

 

Flash Protection Boundary [NFPA 70E]: An approach limit at a distance from exposed live parts within which a person could receive a second degree burn if an electrical arc flash were to occur.

 

Flash Suit [NFPA 70E]: A complete system of fire-retardant clothing and equipment that covers the entire body, except for the hands and feet including pants, jacket, and bee-keeper type hood fitted with a face shield.

 

Opening Door: To move (as a breaker box door) from a closed position by making available for entry, by turning back (as a barrier) or by removing (as a panel cover or obstruction).

 

Qualified Person [NFPA 70E]: One who has skills and knowledge related to the construction and operation of the electrical equipment and installations and has received safety training on the hazards involved.

 

Working On (live parts) [NFPA 70E]: Coming into contact with live parts greater than 50 Volts with the hands, feet, or other body parts, with tools, probes, or with test equipment, regardless of the PPE a person is wearing.

 

 

  1. Responsibilities

Only Qualified Person(s) (defined above) are allowed to work on electrical equipment.

Supervisors of Qualified Persons shall ensure that employees comply with the requirements set forth in this program, including the correct use of PPE, that employees are assigned work for which they are qualified, and that appropriate training has been conducted for staff to perform their jobs safely. Supervisors are also required to ensure the availability of the correct PPE for their employees.

Individuals opening or exposing energized electrical wires or equipment are responsible for assessing the requirements of this guideline and taking appropriate measures to protect themselves and others from potential arc flash hazards. These measures include confirming and wearing the correct PPE. Ensuring the PPE is in good repair prior to use and replaced when found not to be in good repair.

Employees will perform only those tasks for which they are qualified, shall understand the basic principles of high voltage electricity, hazardous energy control and electrical safety procedures. Employees shall use the proper tools and required PPE and shall request supplemental training and information whenever necessary.

 

  1. Training

 

 

  1. Employees who are exposed to an electrical hazard that is not reduced to a safe level by the installation must be trained. Training could consist of classroom, webinars, on-the-job training, or any combination thereof.
  2. The level of electrical safety training provided is dependent on whether the employee is classified as a “qualified person” or “unqualified person”.
  3. A qualified person shall be trained and knowledgeable in all of the following topic:
  • Construction and operation of equipment on which work is assigned.
  • Skills and techniques necessary to distinguish expose energized parts from other parts of electrical equipment.
  • Skills and techniques necessary to determine the nominal voltage of exposed energized parts.
  • The approach distances specified in this document and the corresponding voltages to which the qualified employee will be exposed.
  • The process necessary to determine the degree and extent of electrical hazards along with the PPE and job planning necessary to perform the task safely.
  1. A person can be considered qualified with respect to certain equipment and methods but unqualified for others.
  2. An unqualified person shall be trained in the inherent hazards of electricity and any related work practices that are necessary for their safety.
  3. Training must be provided before the employee is assigned duties that involve work near or on electrical systems.
  4. Each supervisor shall maintain a record of all electrical training provided to their employees along with a listing of all employees classified as qualified person. Training documentation will include content of the training, employee names, and date(s) of the training.
  5. An employee shall receive additional training (or retraining) under the following conditions:
  • If the supervisor indicates that the employee is not complying with the safety-related work practices.
  • If new technology, new types of equipment or changes in procedures necessitate change of safety-related work practices.
  • If he or she must use safety-related work practices that are not normally used during their regular job duties.

 

  1. Safeguarding Electrical Parts and Equipment

Whenever possible, live parts to which an employee might be exposed shall be put into an electrically safe work condition before an employee works on or near them. This may be done by de-energizing and locking out, insulating, or enclosing.

When safeguarding is not feasible, precautions for protection from arc flash and electric shock are required.

  1. “Dead Front” Equipment

Dead front equipment is equipment within enclosures or panels without live parts exposed to a person on the operating side of the equipment. This includes disconnects, control panels, switches, breakers, and motor controls within enclosures with the doors closed and secured.

Arc flash PPE is not required when operating this equipment. It is a recommended practice for electricians and other employees who commonly operate this equipment to wear non-melting clothes and safety glasses.

It is also a good practice when an employee is switching disconnect switches for him/her to stand to the hinge side of door, so that he/she is out of the direct line of fire if a catastrophic fault occurs when the switch is operated. Further protection would be afforded by taking a deep breath and facing away from the switch, before throwing the switch.

  1. Exposure to Arc Flash

The potential for arc flash exists when there is a potential for an electrical current to short circuit. A short circuit occurs when current flows from energized wires or equipment to ground, or between energized wires or equipment with different phases or potential. An arc flash may also occur during movement of energized electrical contactors.

Exposure to an arc flash hazard occurs when a person is close enough to a potential source of arc flash that he/she may be injured if there is no protection such as an electrical enclosure or barrier.

Tasks such as opening electrical panels can result in an exposure to an arc flash hazard and may require protection. Servicing, maintenance, and testing of energized circuits, or within equipment with energized circuits, creates an additional risk for arc flash through accidental contact of tools or equipment with uninsulated energized wires or parts.

Hazard distance requiring the use of PPE is defined by the Flash Protection Boundary.

  1. Flash Protection Boundary

The Flash Protection Boundary is the distance from a potential source of arc flash within which arc flash PPE is required. Inside this boundary, it is estimated that a person could receive a second degree burn if an electrical arc flash were to occur. Entry into the Flash Protection Boundary occurs when the face, head or trunk of the person crosses the boundary.

 

 

Equipment-specific arc flash boundaries may depend upon numerous factors such as available fault level and trip characteristics of the upstream protective device, as determined in an arc hazard analysis. Default Flash Protection Boundaries are provided in this table based on the most conservative assumptions in NFPA 70E and may be used if there are no detailed arc hazard analyses and equipment-specific Hazard Mitigation Plan.

Arc in air (Diagram 1) means unenclosed, so that flash energy is dispersed in all directions. This type of exposure may occur when an employee is testing live wiring outside of an enclosure.

Most exposures will occur with equipment in enclosures (Diagram 2). The enclosure will direct the arc flash energy in the direction of the opening. This protects people away from the opening but increases the energy directed towards anyone in front of the opening.

Limited Approach Boundary - 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. The limited approach boundary is the minimum distance from the energized item where unqualified personnel may safely stand. No untrained personnel may approach any closer to the energized item than this boundary... See Tables 1a and 1b in this document.

Restricted Approach Boundary - A shock protection boundary to be crossed by only qualified persons (at a distance from a live part) which, due to its proximity to a shock hazard, requires the use of shock protection techniques and equipment when crossed. To cross the Restricted Approach Boundary into the Restricted Space, the qualified person, who has completed required training, must wear appropriate personal protective equipment (PPE). Also, he must plan the work to keep all parts of the body out of the Prohibited Space. See Tables 1a and 1b in this document.

 

  1. Personal Protective Equipment (PPE) Classifications

For all work involving potential exposure to energized unguarded or un-insulated electrical equipment and exposure to Arc Flash, non-melting clothing must be worn. Non-melting clothes are natural fibers such as cotton and wool. Synthetic clothing can melt and burn rapidly when exposed to heat or flame and can increase burn injuries. Electrical safety programs will also generally prohibit employees from wearing metallic jewelry and recommend not wearing clothing with metal closures (e.g., zippers, snaps).

In addition to non-melting clothing, the appropriate level of PPE must be worn for tasks in which exposure to an arc flash hazard within the flash protection boundary is possible.

PPE is designated according to Arc Rating. The higher the energy exposure, the higher the Arc Rating expressed in cal/cm2. Typically, Flash Suits and Flash Hoods are rated on the inside tag, expressing what the Arc Rating is for that garment.

Electrical Glove Class (as specified on Arc Flash Labels):

Electrical protective gloves are categorized by the level of voltage protection provided, which are rated by Class. Ozone resistance is noted by Type. Type I gloves are not ozone resistant. Type II gloves are resistant to ozone.

  • Class 00 - 500 Volts Maximum
  • Class 0 - 1,000 Volts Maximum
  • Class 1 - 7,500 Volts Maximum
  • Class 2 - 17,000 Volts Maximum
  • Class 3 - 26,5000 Volts Maximum
  • Class 4 - 36,000 Volts Maximum

Protective Clothing (as specified for Arc Flash in NFPA 70E):

The following levels of protective clothing are specified in NFPA 70E Table for protection from arc flash and on Arc Flash Label. (Glove Class separated in above section)

Level 0 – Non-Melting Long Sleeve Shirt; Non-Melting Long Pants. Safety Glasses.

Level 1 – Minimum Arc Rating 4 cal/cm2. Flame Resistant (FR) Long Sleeve Shirt; FR or Denim Long Pants; FR Coveralls may be used instead of FR Shirt and Pants. Hard Hat (Class E), Arc Rated Face shield, Ear plugs, Leather Work Shoes.

Level 2 - Minimum Arc Rating 8 cal/cm2.  Cotton Underwear plus FR Long Sleeved Shirt; FR or Denim Long Pants; FR Coveralls may be used instead. Hard Hat (Class E), Safety Glasses or Goggles, Arc Rated Flash Hood (20 cal/cm2 or equivalent) or Arc Rated Face Shield, Hearing Protection ear plugs, Leather Work Shoes.

Level 3 – Minimum Arc Rating 25 cal/cm2.  Cotton Underwear plus FR Long Sleeved Shirt; FR or Denim Long Pants; plus FR Coveralls. Hard Hat (Class E), Safety Glasses or Goggles, Arc Rated Flash Suit w/ Hood (40 cal/cm2 or equivalent), Hearing Protection – ear plugs, Leather Work Shoes.

Level 4 -- Minimum Arc Rating 40 cal/cm2. Cotton Underwear plus FR Long Sleeved Shirt; FR or Denim Long Pants; plus Multi-Layer Arc Rated Flash Suit (100 cal/cm2 or equivalent). Hard Hat (Class E), Safety Glasses or Goggles, Arc Rated Flash Suit Hood (100 cal/cm2 or equivalent), Hearing Protection, Leather Work Shoes.

  1. Inspection, Maintenance, Cleaning and Storage of PPE

PPE shall be maintained in a safe, clean, and reliable condition and in accordance with the manufacturer’s’ instructions. For individually assigned PPE, the person to whom the equipment is assigned is responsible for inspection, maintenance, and storage of the PPE. The user must inspect all PPE prior to and after each use for damage and defects. Any damage, defects, or problems with the equipment must be reported to the Responsible Individual. The manufacturer’s recommendations for cleaning and storing shall be followed.

  1. Selection of PPE

PPE for protection from arc flash must be selected by trained and qualified employees. Training and authorization must be appropriate for the level of energy and type of PPE being used.

 

Selection of PPE is task and equipment based (for covered equipment not already labeled with specific Arc Flash Specifications).

 First follow table in Section 12 to determine whether Arc Flash PPE is required. If Arc Flash PPE required, then determine what PPE level is required in sections 13 and 14 (AC equipment and DC equipment) along with Arc Flash Boundaries.

  1. Arc Flash Hazard Identification for AC and DC Systems/equipment not already labeled.

 

  1. Arc Flash Hazard PPE Level and Arc Flash Boundary for non-labeled covered AC equipment.

 

  1. Arc Flash Hazard PPE Level and Arc Flash Boundary for non-labeled covered AC equipment continued. 

 

  1. Arc Flash Hazard PPE Level and Arc Flash Boundary for non-labeled covered DC equipment.