During presentations I've given over the last several years, I'm always struck by the number of contractor questions I receive concerning implementing the National Fire Protection Association's Standard for Electrical Safety in the Workplace (NFPA 70E). Although I agree that in some situations it can be more difficult for a contractor (working on multiple jobsites for a number of different customers) than a manufacturing plant to implement safe work practices outlined within the standard, it's by no means impossible. Adherence to this standard is critical to the success of your electrical safety program and your business.
Not only should you use NFPA 70E as a reference for conducting hazard assessments and making personal protective equipment (PPE) selections, but implementing the standard's requirements within your safety program may also be used as evidence that you have acted reasonably should OSHA enforcement actions or litigation develop following an accident.
Delivering due diligence. As an employer, you are responsible for creating a safe workplace and enforcing written safety procedures. You should begin by establishing your own electrical safety program — one that includes an organized approach and prevents injuries and property damage by eliminating hazards, eliminating exposures, and using PPE.
Your company needs to create policies for working around energized components, provide training to qualified and unqualified workers, and establish safe work practices such as the use of ground fault circuit interrupters with extension cords, lockout tagout procedures, and protective grounding equipment. Once the program is established, it must be audited to ensure compliance. Referencing publications such as “The Electrical Safety Program Book,” published by NFPA, can help you establish your basic program elements.
You should also review your test instruments to be sure they are “category rated” for the type of work they will be required to perform. Emergency response procedures should be established, and your employees should be trained in first aid, CPR, and automated external defibrillator (AED) use. Finally, you should have a policy for conducting a job briefing before and after the work is completed. This review can help to ensure a safe efficient installation and understand any unanticipated situations encountered. How can NFPA 70E help you in these efforts?
Do the right thing. NFPA 70E is a “how-to” guide for implementing the electrical safety requirements of OSHA. It is a “best practice” of how workers can be protected from electrical hazards operating under certain conditions that should be used as the minimum requirement when establishing your program. NFPA 70E applies to most workplace environments and specifically to workers who are exposed to energized parts over 50V, which includes diagnostic and troubleshooting activities.
Most of us have seen pictures of grotesque burn injuries and heard industry statistics on the startling number of fatalities and injuries attributed to electrical incidents. Those examples should be enough to influence you to improve safe work practices. If you don't believe that you should create a safe workplace for your employees for the “right” reasons, consider the impact that non-compliance may have on your livelihood.
Ignoring electrical safety rules and regulations can lead to governmental citations, insurance premium increases, catastrophic medical costs, large litigation settlements, equipment damage, customer downtime, loss of corporate reputation, bankruptcy, and even criminal prosecution. Simply stated, implementing an effective electrical safety program is just good business.
De-energize whenever possible. The most important element in preventing unnecessary incidents and injury is to place equipment and conductors in an “electrically safe work condition” before performing work. In most instances, this can be accomplished with forward planning with your customer.
NFPA 70E, Section 110.4 provides information about the responsible obligations required of both parties. De-energized infeasibility, as a defensible position, is mainly limited to life safety or continuous process examples and not after-hour's work or customer inconvenience. A written agreement between you and the equipment owner, including a justification for live work permits, should be completed and signed by both parties before work is initiated.
An example of an Energized Work Permit is located in Annex J of the NFPA 70E standard. When you approach your customer and ask them to sign an energized work permit, in many instances they will typically find an acceptable way to de-energize the equipment. Remember, both parties could share liability if an injury occurs. If you cannot get a signed agreement, you should either refuse to do the work or work energized after conducting a shock and flash hazard analysis.
Conduct a hazard analysis. Conveniently, NFPA 70E provides tables that can help with both instances. Shock hazard approach boundaries are a function of the voltage level and clearance distances. Table 130.2(C) provides those distances. Combining these dimensions with the boundary definitions is a fairly straightforward process. Flash hazard/risk category classifications can either be obtained from the task specific Table 130.7(C)(9)(a) or by calculating the flash protection boundary (FPB) and the incident energy level at 18 inches using the formulas provided.
The dilemma when using the tables as well as the 70E formulas is that the fault current and opening time of the overcurrent device must be known. This becomes evident when the table notes for tasks at 600V or less be properly applied. In either example, you can then continue on to Tables 130.7(C) (10) and (11) to select your PPE required to perform the energized work successfully. Remember: If your calculation reveals incident energy above 40 cal/cm2, do not attempt to perform the work in an energized condition — NFPA 70E places the maximum workable incident energy at 40 cal/cm2 due to the devastating effects of arc blast.
As stated above, in order to determine the FPB and incident energy level you will need to have the available short-circuit current magnitude and device clearing times of that portion of the system you're working on. An additional source of information including kVA, impedance, fuse characteristics, and voltage can be provided by your local utility or by reviewing the nameplate rating of the distribution transformer that feeds the building.
Electrical systems also need to be maintained to ensure that they will operate as designed. Accurate single line drawings need to be updated and verified. Current limiting overcurrent protective devices must be installed to reduce the available short-circuit current. “Finger-safe” covers should be installed to prevent contact with energized parts. Circuit breakers and protective relays should be tested periodically. Finally, system-wide flash hazard analysis needs to be performed, and equipment should be labeled. As a final line of defense, strict PPE practices should always be followed.
The importance of PPE. Protection is required against shock hazards at and above 50V. This will necessitate the use of gloves in most instances, including performing diagnostic and troubleshooting activities. You should also consider the use of gloves on high current systems fewer than 50V if a burn or shock hazard exists. Once the gloves are placed into service, they must be tested every six months and inspected before each use. Although not rated for this purpose, insulated gloves and their leather protectors provide a degree of protection from an arcing fault.
Injuries are caused by burns suffered when clothing is ignited in an arc flash incident. In many instances, this clothing continued to burn long after the arc had subsided. For this reason, you should invest in fire-resistant (FR) clothing for your employees. FR clothing can help mitigate the extent of burn injury because of its self-extinguishing nature. This clothing should be used as “everyday wear” and should consist of an FR long sleeve shirt and FR trousers.
These garments can either be purchased or rented through a laundry supplier and typically have an Arc Thermal Performance Value (ATPV) of approximately 4 to 8 cal/cm2. Garment suppliers can also provide the expertise to clean and repair the garments as required. When warranted by the incident energy levels encountered, higher ATPV-rated garments should be readily available and required to be used by your employees. Additionally, any outerwear worn as thermal insulation or for protection from the rain must also be arc rated.
Head and face protection like hard-hat/face shield combinations and arc hoods are required to reduce thermal burns, protect against flying particles, and filter out ultraviolet radiation all produced in an arc flash. These devices are designed as secondary eye protection so safety glasses must be worn beneath. Hearing protection and leather footwear are also required for exposures at 8 cal/cm2 or greater.
Obviously, every work situation has its own unique set of requirements. However, following steps such as those outlined in this article will get you well on your way to protecting your people and your business.
Editor's note: This article does not constitute an official position of NFPA or the T.A. Edison Institute.
Drobnick is a principal member of the NFPA 70E technical committee and a featured presenter for the T.A. Edison Institute.