FAQs

Frequently Asked Questions


According to NFPA 70E Standards for Electrical Safety in the Workplace there are two potential methods for determining arc flash PPE.

  1. The incident energy analysis method in accordance with table 130.5(G)
  2. The arc flash PPE category method in accordance with table 130.7(C)(15)

Depending on which method is used the tables in NFPA 70E can help you identify what arc flash PPE is required.  Table 130.7(C)(15) has been recreated by Oberon and can be used to assist you in identifying what arc flash PPE you should select when using the arc flash PPE category method.

If you are using the incident energy method to select your arc flash PPE the recreated NFPA 70E Table 130.5(G) listed below can be used as a reference.  Please reference NFPA 70E Standards for Electrical Safety in the Workplace directly for any specific questions on the guidelines listed in this FAQ.

Incident energy exposures equal to 1.2 cal/cm2 up to 12 cal/cm2

  • Arc-rated clothing with an arc rating equal to or greater than the estimated incident energy level.
  • Long-sleeve shirt and pants or coverall or arc flash suit
  • Arc-rated face shield and arc-rated balaclava or arc flash suit
  • Arc-rated outerwear (e.g. jacket, parka, rainwear, hard hat liner)
  • Heavy-duty leather gloves, arc-rated gloves, or rubber insulating gloves with leather protectors
  • Hard hat
  • Safety Glasses or safety goggles
  • Hearing protection
  • Leather footwear

Incident energy exposures greater than 12 cal/cm2

  • Arc-rated clothing with an arc rating equal to or greater than the estimated incident energy level.
  • Long-sleeve shirt and pants or coverall or arc flash suit
  • Arc-rated arc flash suit hood
  • Arc-rated outerwear (e.g. jacket, parka, rainwear, hard hat liner)
  • Arc-rated gloves or rubber insulating gloves and leather protectors
  • Hard hat
  • Safety Glasses or safety goggles
  • Hearing protection
  • Leather footwear

There are many standards involved when dealing with electrical safety in the workplace.  NFPA 70E and CSA Z462 both help to lay the groundwork for companies to create electrical safety programs that protect the welfare and safety of their workers.  While these standards are a great reference for companies to review, they can not cover all situations or environments.  In Article 90 of the NFPA 70E standards certain industries are excluded and are listed below.

  1. Installations in ships, watercraft other than floating buildings, railway rolling stock, aircraft, or automotive vehicles other than mobile homes and recreational vehicles.
  2. Installations of railways for generation, transformation, transmission, or distribution of power used exclusively for operation of rolling stock or installations used exclusively for signaling and communications purposes.
  3. Installations of communications equipment under the exclusive control of communications utilities located outdoors or in building spaces used exclusively for such installations.
  4. Installations under the exclusive control of an electric utility.
These exclusions create some confusion on what to reference should electrical work need to be on installations of this nature.  The National Electric Safety Code or NESC attempts to solve this issue by providing ground rules for safeguarding of persons during the installation, operation, or maintenance of power, telephone, cable TV,, and railroad signal systems.  This is of particular importance when discussing Arc Flash PPE.  Since the installations listed above are not covered by NFPA 70E standards, they will refer to NESC guidelines when selecting Arc Flash PPE.
In Part 4, Section I of the NESC guidelines it states the following.
  • I. Clothing
    1. Employees shall wear clothing suitable for the assigned task and the work environment.
    2. When employees will be exposed to an electric arc, clothing or clothing system shall be worn in accordance with Rule 410A3.
    3. When working in the vicinity of energized lines or equipment, employee should avoid wearing exposed metal articles.
If we then look at Rule 410A3 it states that if an assessment determines a potential employee exposure greater then 2cal/cm2 exists that the installation should, “Require employees to cover the entire body with an arc rated clothing and equipment having an effective arc rating not less than the anticipated level of arc energy.”   This requirement does not stipulate the specific type of Arc Flash PPE to be used, just that it is appropriately rated and covers the entire body.  As a result, workers such as Powerline Technician may have a need for a 20+ cal/cm2 ensemble that allows for maximum flexibility while working.  Oberon Company created an arc flash kit for just such occasions.  It is consists of a coverall, hard cap and shield, balaclava, and kitbag.  All of the components of this kit are rated to protect the worker up to exposure levels of 25 cal/cm2.  We call this kit the TCG25-CKE-NB Series.
When you are involved in an arc flash two things occur simultaneously and help prevent damage to your eyes.  1) You blink.  This happens very quickly.  A good example of this at work would be when you accidentally look at the sun.  Your first reaction is to immediately close your eyes. The blinding flash of an arc lasts as long as the arc flash is present. This would be about one third of a second for a 12 calorie arc flash and up to 2 seconds for a 100 calories/cm2 arc flash.  The human eye response is about 1/10th of a second to blink.  Therefore in about 1/10th of a second in all arc flashes the eye blinks to reduce the visible light reaching the eye.  While we do not want to overexpose the eye to this visible light there is a natural response and self-limiting mechanism.  2) A second protective mechanism occurs in our TCG™ Shields when they are hit with an arc.  There are additives in the shields that will carbonize in about 1/10th of a second.  This carbonization will reduce all of the electromagnetic spectrum and most of the arc flash visible light. Essentially the front surface looks a lot like asphalt moss once it is hit with an arc flash.  Please see the attached picture for reference. The combination of these two things prevents any significant damage to the eyes from occurring.

 

The user has 12 months from the test date to put new gloves into service. It is important to note that the user must document when the gloves are put into service to comply with OSHA 1910.137 guidelines.

The manufacturer of Oberon gloves electrically tests every glove prior to shipment. Each “batch” of gloves is also subjected to a battery of physical and electrical tests to insure that the gloves meet the D120 Standards. It is the responsibility of the employer to insure that the gloves have passed the required electrical test within the specified time.

Leather protectors should always be worn with rubber insulating gloves. ASTM F696 provides the specification for the manufacture of Leather Protectors. Leather protectors are sized to be worn on the same size rubber insulating glove so if you wear a size 10 rubber insulating glove you should order a size 10 leather protector.

ASTM D120 section 8.2 provides the measurements of the diameter of
the palm for manufacturers, measured at the midpoint of the palm, plus or minus 1⁄2”. Measure your hand by wrapping the tape all the way around your palm at the point shown to the right. This would equate to the probable size of glove to select. Personal preference for tightness and finger length will ultimately determine the size that you are most comfortable wearing.  Please see the attached glove sizing guide below.

Rubber Insulating Gloves are designed and constructed to act as a barrier between the user and the energy/voltage,to insulate the user from electric shock. The ASTM D120 standard outlines the protection that the glove provides. The rubber gloves are thicker as their protection increases. The rubber gloves will provide protection against either Alternating Current (AC) as well as Direct Current (DC), up to the levels detailed in the standard as well as typically onthe labeling, which is required to be affixed to each glove. It is important NOT to exceed the USE voltage detailed to avoid injury.

29 CFR 1910.137(c)(2)(ii) requires an air test be performed along with inspections for insulating gloves. ASTM F 496 also specifies air tests for the in-service care of insulating gloves and sleeves. Basically, the glove is filled with air (either manually or with a power inflator) and then checked for leakage.  As stated in ASTM F 496, Type I gloves should be expanded no more than 1.5 times their normal size during the air test and Type II gloves no more than 1.25 times. The procedure should be repeated after turning the glove inside out.

OSHA requires that “protective equipment be maintained in a safe, reliable condition.” Gloves should be inspected for tears, holes, ozone cuts and other defects before each use. For more information, refer to the ASTM F 1236-16 standard guide for the visual inspection of electrical protective rubber products.  Also, gloves should be inspected for any swelling, which is generally caused by chemical contamination (specifically petroleum products). Even the slightest swelling can be an issue.  If the electrical gloves show any signs of the defects discussed above upon inspection, they should be taken out of service for cleaning and retesting (even if it hasn’t met the six month “in-service” rule or the 12-month shelf life rule discussed in the date stamp section of this article) per ASTM D120-14a requirements.