Electrical Safety

NEC 2020 Enhances Service Entrance Safety

EP Editorial Staff | June 12, 2020

Recent NEC Code changes enhance protection when installing or maintaining electrical-service entrances, which can be one of the most dangerous places in the power-distribution system.

Four key changes to the National Electrical Code result in significant safety advances for electrical workers.

By Thomas Domitrovich, P.E., LEED AP, Eaton

Following the 2020 National Fire Protection Association (NFPA), Quincy, MA (nfpa.org), annual conference, members agreed on four key NEC (National Electrical Code) changes designed to increase electrical safety and provide additional protection that will help enhance protection for persons and property at service-entrance applications, potentially the most dangerous place within the power-distribution system.

Short-circuit current rating

Effective January 1, 2023, pressure connectors and devices used for splices and taps must be marked as “suitable for use on the line side of the service equipment” or equivalent. This new short-circuit current rating requirement parallels changes that affected power-distribution blocks (PDBs) from the 2017 cycle, but now addresses other types of termination devices. The update has far-reaching implications for manufacturers.

Rationale: The 2017 label change only accounted for one type of solution used in that application. The 2020 update now requires marking all termination types, including PDBs, pressure connectors, and devices for splices and taps used in these locations, as suitable for use on the line side of service equipment to assure connectors are tested for given locations in the circuit. Manufacturers currently don’t build devices for use on the line side of service equipment, so manufacturers and standards developers must quickly bring solutions to market. The requirement’s effective date offers manufacturers leeway to bring products up to speed.   

Safety disconnect

Language now exists in Section 230.85 for emergency disconnects (formerly the firefighter disconnect) on the exterior of one- and two-family dwelling units so that first responders may quickly disconnect power to a structure. Language in Section 445.18 also addresses emergency generator shutdown.

Rationale: In addition to fire, gas leaks, and other dangers, first responders often must account for electrical hazards during emergencies. These situations can be chaotic, requiring responders to ventilate buildings on rooftops, break through windows, and open walls in seconds. With that, there’s a real danger of coming in contact with energized conductors and equipment.

Typically, first responders look to turn the power off before entering a blaze, but many residential panelboards are in basements. Terminating power at the transformer, which could be atop a pole, is not something any untrained person should attempt. This change mandates placing emergency disconnects near the service- entrance equipment outside of a structure.

Concerns were raised during requirement debates that safety disconnects allow anyone to terminate the power to a home. The NEC’s response was to allow installation of disconnect locks to thwart unauthorized power access. While the locks will not impede firefighters or other first responders and may provide a level of comfort to the owner, contractors will still have to explain the expense of safety disconnects, especially in locations where it’s not common practice to add outdoor service panelboards.

Line-side barriers and six disconnect rule

What many refer to as “the six disconnect rule” was modified per Section 230.71 such that service panelboards without a main and six or fewer disconnects will no longer be permitted. Hazards associated with six disconnects without a main in a service panelboard have always been a concern. Changes in 2017 to NEC Sections 110.16, 240.87, 240.67, and 408.3 furthered that awareness and inspired more change during the NEC 2020 development process. 

The changes in the latest cycle provide options on leveraging as many as six disconnects instead of a single main overcurrent protective device (OCPD), with a how-to section outlining four options:

• separate enclosures with a main service disconnect
panelboards with a main service disconnect
switchboards with only one service disconnect and barriers separating each vertical section
service disconnects in switchgear/metering centers with disconnects located in separate compartments.

In addition, line-side barrier requirements are expanded to service equipment beyond panelboards and switchboards.

There are two reasons for the change:

Exposing hazards. The NEC changed Section 408.3 in 2017 to require barriers on service-entrance panelboards, recognizing that adding line-side barriers on panelboard service disconnects may not be possible with six disconnects used in the same panelboard. This decreased the likelihood of workers coming in contact with energized terminations on the line side of the main service OCPD or switch. However, one panelboard with six means of disconnect with no main circuit breaker results in electrical workers lacking the ability to apply barriers to the line side of each overcurrent device because the line side is a bus. The 2017 NEC update included an exception for these types of applications.

The 2017 Code focused on panelboards, switchboards, and low-voltage assembly solutions, but warranted an exception since technicians can’t barrier the line side of six disconnects in a panelboard. The NEC removed the exception in the 2020 update by including transfer switches, feasible disconnect switches, and others with catch-all language.

Better personal protection. NEC 2017 changed Section 110.16 to require marking service equipment with available fault current, clearing times, and date of installation to help determine personal protective equipment (PPE). With six disconnects used in the same panel, six distinct clearing times must be labeled on the equipment. This update to an obvious safety hazard has inspired electrical professionals to look at installations more closely. Since exposed energized buses in service panelboards do not have upstream OCPDs outside of the fuse on the primary/utility side of the transformer, the NEC 2020 changes to labeling requirements raise awareness of hazards associated with six disconnects in the same enclosure.

Arc reduction

Arc-reduction requirements have expanded during every review cycle since their introduction in 2011. While not for service equipment per se, this requirement is intended for any circuit breaker or fuse 1,200 amps and higher and recognizes those applications are prone to high incident energy due to the longer clearing times of devices at these ampere levels. By raising awareness of service-entrance equipment hazards that lack upstream OCPDs, the changes help reduce the likelihood of exposure to an energized bus.

Aside from manufacturers creating new code-compliant products, technicians may need to review their designs against new requirements and will likely need to change the way they plan future projects. Some believe the changes could have a financial impact on businesses. Resourceful contractors will find ways to meet the Code while becoming more cost-efficient.

Surge protection

The NEC recognizes in Section 90.1(A) that the purpose of the Code is practical safeguarding of persons and property from hazards arising from the use of electricity. Updates to surge protection are twofold. First, Article 242, titled “Overvoltage Protection,” does not add new requirements but rather consolidates surge requirements from around the NEC to draw attention to performance issues that align with circuit applications. Second, Section 230.67 now mandates services supplying dwelling units shall be provided with a surge-protective device (SPD) as an integral part of equipment or located immediately adjacent, either Type 1 or Type 2 SPD.

Rationale: The surge requirement change is all about usability. The NEC has made the requirement easier to navigate and implement, which increases the likelihood of proper installation.

Protecting people is a key driver for surge protection clarification and expansion. The requirements provide for life-safety products, such as AFCIs, GFCIs, and smoke detectors. An argument can be made that the Code goes beyond life safety to include protection of property. Loss isn’t always devastating; something as small a losing a TV or appliance to surge isn’t life-threatening, but it is a nuisance that results in higher insurance premiums.

For years, the NEC has anticipated stronger protections for those who work on service equipment. With the updates passed by the NFPA, the Code enhances protection for workers and the equipment they service. As with any requirement update, feedback from professionals in the field is extraordinarily important. It’s vital that everyone in the electrical field explore articles in their purview that could benefit from enhancement. The industry has the capacity to make proactive changes, because many 2020 updates were inspired by professionals who knew that more could be done to enhance safety. EP

Thomas A. Domitrovich is an electrical engineer at Eaton (eaton.com), electrical business. He has experience in engineering, sales & marketing, business development, and product management and is involved with various electrical industry organizations.


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