While some may perceive a fine line between NFPA 70, the National Electrical Code, and NFPA 70E, Electrical Safe Work Practices, I see two documents working in harmony. And there is a lot more potential to be had.
Understanding how various codes and standards interact requires careful analysis. NFPA 70 and NFPA 70E demonstrate effective collaboration. Some critics reject including Arc Flash and incident energy in the NEC, arguing that NFPA 70E alone should address these issues. I believe NFPA 70 needs stronger requirements to address incident energy and better mitigate arc flash risks. Let’s examine how these documents work together and explore ways to create a safer electrical environment for everyone.
An Accepted Harmony
These two documents work together in many aspects of electrical safety, with numerous complementing requirements demonstrating their synergy. However, they have largely overlooked incident energy and arc flash until recently. Over the years, progress has fallen short. They already collaborate effectively in areas like electrical shock protection, illumination, and lockout/tagout, but opportunities for improvement remain. Their natural harmony stands clear, and efforts should continue to strengthen it.
Developing the roadmap to address incident energy requires understanding existing successes in other areas of electrical safety.
Shock Protection
Shock protection requirements in NFPA 70 align well with requirements of NFPA 70E. There are direct relationships and indirect relationships that can be built upon.
NFPA 70
210.8 Ground-Fault Circuit-Interrupter Protection for Personnel
GFCI protection is required as part of this section for various applications that include receptacle outlet and hard wired outlet applications.
NFPA 70E
110.8 Ground-Fault Circuit-Interrupter (GFCI) Protection.
GFCI protection is required as part of this section for electrical workers where required by applicable state, federal, or local codes and standards.
I want to highlight the following language: “. . . where required by applicable state, federal, or local codes and standards.” This directly references code adoption. The National Electrical Code is not adopted uniformly or immediately across all states. In fact, some states are still operating under the 2008 edition. For more details, refer to this online resource from the NFPA.
Comparing these two documents on shock protection reveals important insights. Examining the topic of GFCIs shows how installation requirements align with safe work practices. As you explore these comparisons, consider whether they should be better aligned.
NFPA 70
210.8(A)(3) Outdoors requires all 125-volt through 250-volt receptacles installed in the following locations and supplied by single-phase branch circuits rated 150 volts or less to ground to be GFCI protected.
210.8(B)(6) Outdoors requires all 125-volt through 250-volt receptacles supplied by single-phase branch circuits rated 150 volts or less to ground, 50 amperes or less, and all receptacles supplied by three-phase branch circuits rated 150 volts or less to ground, 100 amperes or less to be GFCI protected.
210.8(F) Outdoor requires that all outdoor outlets be provided with GFCI protection but limits this only to dwellings and specifically 3 areas.
NFPA 70E
110.8(C) Outdoors
This section requires GFCI protection when an employee is outdoors and operating or using cord sets or cord- and plug-connected equipment that is supplied by 120-volt, 15-, 20-, or 30-ampere circuits.
I haven’t addressed other areas including lock-out Tag-out where the NEC has installation requirements like the following:
Where is the opportunity to strengthen the relationship between NPFA 70 and NFPA 70E? What if NFPA 70E did not rely on what local codes and standards have been adopted, but rather what local codes and standards have been published as of the date of 70E. These two documents work well together, but not when the latest edition of 70E is referencing an installation requirement that is 17 years old. Just think about the state adoption of NFPA 70 across the country. You have the latest requirements of 70E that state you need to have GFCI protection or working space as per the latest code that has been adopted. The latest code that has been adopted in some states is 17 years old.
Think about the discrepancy and then imagine the opportunity.
Illumination
Illumination plays an important role in electrical safe work practices and is very much a part of the installation requirements found in the national electrical code. Let’s walk through some comparisons in this regard.
NFPA 70
210.70 Lighting Outlets Required
(C) All Occupancies
Requires a lighting outlet where identified spaces are used for storage or contain equipment requiring servicing. Where installed for equipment requiring service, the lighting outlet shall be installed at or near the equipment.
NFPA 70E
130.8 Other Precautions for Personnel Activities.
(C) Illumination
Requires that employees not enter spaces where electrical hazards exist unless illumination is provided that enables the employees to perform the work safely.
Illumination plays a critical role in electrical safety and safety in general. Lighting an area provides the ability to clearly see potential hazards, obstacles, and more. The act of illumination does not reduce severity of an event but does reduce risk through reducing likelihood.
Lockout / Tagout
Lockout/Tagout (LOTO) procedures are pivotal safeguards in ensuring electrical safety. The National Electrical Code (NEC) and NFPA 70E include critical requirements underscoring LOTO indispensable role in mitigating electrical hazards. These regulations are designed to protect personnel from the dangers of unexpected energization or startup of machinery and equipment during maintenance, servicing, or repair activities. By adhering to LOTO protocols prescribed by both the NEC and NFPA 70E, organizations not only comply with legal mandates but also prioritize the well-being of workers, thereby fostering a secure working environment conducive to productivity and safety.
NFPA 70
110.25 Lockable Disconnecting Means.
Specifies that If a disconnecting means is required to be lockable open elsewhere in this Code, they must be capable of being locked in the open position. The provisions for locking shall remain in place with or without the lock installed.t.
495.46 Circuit Breaker Locking.
Circuit breakers shall be capable of being locked in the open position or, if they are installed in a draw-out mechanism, that mechanism shall be capable of being locked in such a position that the mechanism cannot be moved into the connected position. In either case, the provision for locking shall be lockable open in accordance with 110.25.
NFPA 70E
Article 120 Establishing an Electrically Safe Work Condition
An entire article is dedicated to establishing an electrically safe work condition and lockout/tagout is at the heart of these requirements as witnessed by the sections within.
120.2 Lockout/Tagout Program
120.3 Lockout/Tagout Principles.
120.4 Lockout/Tagout Equipment.
120.5 Lockout/Tagout Procedures.
I want to highlight the following language: “. . . If a disconnecting means is required to be lockable open elsewhere in this Code.” The question that is in my head relates to what circuit breaker would you not want to be provided with a means to lock in the open position? After all, they are the beginning of a conductor that supplies power to something that will, at some point, require maintenance or similar activities. Establishing an electrically safe work condition should not be compromised and the NEC should facilitate this action for all applications not just some.
As I said above, there is room to improve the existing requirements. Change begins with knowledge. Understand where we’ve been, where we are and where we want to go.
working Space
Before we address the topic of arc flash, it must be recognized that working space plays a key role in all electrical hazards. Having adequate working space reduces likelihood of shock, arc flash, arc blast and thermal burns. Remember that working space does not reduce the severity of an event should one occur.
NFPA 70
110.26 Spaces About Electrical Equipment
“Working space, and access to and egress from working space, shall be provided and maintained about all electrical equipment to permit ready and safe operation and maintenance of such equipment. Open equipment doors shall not impede access to and egress from the working space.”
NFPA 70E
205.6 Spaces About Electrical Equipment.
All working space and clearances required by electrical codes and standards shall be maintained.
Proper working space should be a focus for all designs. Placement of equipment is a decision that is critical to the electrical worker well after the installation is completed.
The NEC has working space requirements but there are exceptions and requirements for specific applications. Care should be taken when implementing those exceptions. Make the right decisions in design that benefit the future.
Working space cannot be emphasized enough. All too often we just accept what we’re given but that doesn’t have to be the case if care is taken during the design and layout of a project. There are tools available to help with “perspective” to help designers understand proper placement of equipment and not just electrical equipment. It is not unrealistic to recognize that mechanical or other trades can and do encroach on working space for electrical equipment. A holistic approach to design is essential.
Arc Flash
So now on to the main course. A foundation of understanding on the areas discussed thus far regarding where NFPA 70E and NFPA 70 successfully dance in harmony, is critical to understanding if there are opportunities around incident energy / arc flash.
As it stands today, the National Electrical Code has three areas where the arc flash hazard is specifically addressed. Keep in mind that the code cn impact two key areas of risk including likelihood and severity. Let’s review each of the areas of the code where requirements directly pertain to incident energy / arc flash and categorize these into what portion of risk that they impact.
110.16 Arc-Flash Hazard Warning.
Section 110.16 became a part of the NEC with its introduction into the 2002 version of the NEC. The goal of the submitter was not directly achieved with the new requirements of 110.16 as the Code making panel debated and arrived at the marking of a hazard warning in this section instead of an actual arc flash label which was being sought by the submitter. The submitter was working to achieve a marking of incident energy.
Keep in mind that this was the same year that IEEE 1584, “Guide for Performing Arc-Flash Hazard Calculations”, was published. The substantiation used during that code cycle noted that “Significant number of electricians are being seriously burned and often killed from an accidental electrical flash while working equipment ‘hot’. Most of these serious accidents can be eliminated or significantly reduced if the electricians wear the proper type of protective clothing. If switchboards, panelboards, loadcenters, and motor control centers were individually marked with the incident energy, the personnel would easily know what type of protective clothing to wear, because its rating is based upon the available incident energy in calories per square centimeter.”
230.95 Ground-Fault Protection of Equipment
Ground-fault protection of equipment (GFPE) was introduced in 1971 to address the massive destructive forces of arcing ground faults occurring in service entrance equipment. The industry at this time was moving from ungrounded delta systems to grounded wye, from 208 volt to 480V and increasing services from 600A to 4000A. Catastrophic events releasing the destructive forces of arcing faults were documented at service entrance equipment and becoming a problem. The latest technology available on the market at that time, GFPE, was the best the industry could do to address the problem.
47 years have passed since the introduction of GFPE to the National Electrical Code (NEC) to solve a problem that we know significantly more about today than ever before (especially when one considers all the work and research on incident energy calculations for arcing faults). A problem that has more solutions today than ever before. This article will review GFPE and associated NEC requirements based on what we’ve learned during 47 years of research and product development.
Changes to the NEC will generate an industry swell of discussion and debate around controversial topics. It was shortly after the introduction of this new requirement that Dunki-Jacobs authored an IEEE paper on the topic of arcing ground-faults. (Dunki-Jacobs, The Effects of Arcing Ground Faults on Low-Voltage System Design, 1972) In his paper, Dunki-Jacobs recognized that the issue of arcing ground-faults are relatively new to the industry and he made some observations as to the circumstances that impacted the increase of these events. The following 3 reasons were provided:
- Ungrounded to grounded systems: The industry at this time was moving from ungrounded delta systems to 480Y/277 V solidly grounded systems. Ground-fault currents were of magnitudes greater on these new grounded systems than those experienced on ungrounded systems.
- 208 vs. 480 volt systems: In addition to moving from an ungrounded system to a grounded system, the voltage was also increasing. Dunki-Jacobs noted that in the lower voltage system, arcing faults would self-extinguish while in the higher voltage system the arc can be sustained causing increased damage.
- Increased service ampere ratings: To compound these issues service equipment moved from 600A to as high as 4000A. With this change came overcurrent protective devices with trip curves permitting longer delays at higher currents.
This paper revealed to the industry some important information regarding the problem that was being experienced. Dunki-Jacobs noted that “It is the energy of this arc which releases a tremendous amount of heat in an extremely short time. The surrounding air heats up, building up pressures which blow open doors and cause copper or aluminum buses to be melted away in a matter of seconds or less. Most surprisingly, this large amount of energy is released at fairly low current levels. The usual phase-overcurrent direct-acting trips may not always sense these low level arcing faults within a reasonably short time. It is therefore appropriate to gain an understanding of the current limiting effects of arcing faults.” (Dunki-Jacobs, The Effects of Arcing Ground Faults on Low-Voltage System Design, 1972)
240.87 Arc Energy Reduction
It wouldn’t be until 2011, 40 years after the introduction of GFPE, that NFPA-70 would see the next installation requirement for an arc reduction technology. NFPA 70-2011 was the first introduction of Section 240.87 which introduced technology to begin the journey of addressing the incident energy issue that was not solved through the introduction of 230.95 GFPE requirements. Over the years this section has been refined but focuses on providing arc reduction technologies for the electrical worker.
The first introduction of this requirement in 2011 focused on circuit breakers without an instantaneous. These types of circuit breakers are power circuit breakers and are rarely seen in general application.
It was during the NFPA 70-2014 cycle that the realization occurred that the impact is very limited. 240.87 was then expanded to include all circuit breakers 1200Amps and larger. The options were also expanded beyond the initial three which included zone selective interlocking, differential relaying and the energy-reducing maintenance switching with local status indicator.
NFPA 70-2017 saw a few more options added to the list but the section withstood much scrutiny and proposals and comments to remove it from the code.,
Over the years, this section has been massaged but time will tell on what the next portion of the journey holds for 240.87.
240.67 Arc Energy Reduction
Section 240.67 This section was first introduced as part of NEC 2017 but had an effective date of January 1, 2020. The requirement addresses fuse applications where the fuse is 1200A or larger. There are options that must be employed only when the arcing current has a clearing time longer than 0.07 seconds. These options include:
- Differential relaying
- Energy-reducing maintenance switching with local status indicator
- Energy-reducing active arc-flash mitigation system
- Current-limiting, electronically actuated fuses
- An approved equivalent means
This section was introduced after the requirements were placed in 240.87.
When will the experts realize that the ampere rating of the OCPD is not the deciding factor when it comes to incident energy. it’s all about current and time.
Closing Remarks
I hope that this post helped in understanding the relationship between NFPA 70 and NFPA 70E and sparked some thought around the opportunities that exist. We’ve walked through some examples to demonstrate the chemistry that exists between these two documents. We have work to do to strengthen the relationship through a conscious effort of strategic public inputs and comments future future editions of both documents.
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