NEC 2020 enhances four foundational elements of service entrance and surge protection

Short circuit current rating

The 2020 change

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


The rationale for change

The 2017 label change only accounted for one type of solution used in that application. The 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.



What might the future hold?

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.

"The changes passed enhance protection for persons and property at service entrance, potentially the most dangerous place in the power distribution system."
Thomas Domitrovich, Eaton vice president, technical sales

Safety disconnect (formerly the firefighter disconnect)

The 2020 change

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

The rationale for change

Aside from fire dangers, first responders often must account for electrical hazards during emergencies. Fires are chaotic, with firefighters rushing to ventilate buildings on rooftops, breaking through windows and opening 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 homes' 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. 

What might the future hold?

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 the 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 homeowner, 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. When bidding on new jobs, technicians should stress the importance of safety to justify costs to consumers. 

Line side barriers and the six disconnect rule

The 2020 change

What many refer to as "the six disconnect rule" was modified per Article 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; 2017's changes in NEC Articles 110.16, 240.87, 240.67 and 408.3 during the 2017 review cycle furthered that awareness and inspired more change during the NEC 2020 development process.

The changes in the latest cycle provide options on leveraging up to 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 expanded to service equipment beyond panelboards and switchboards.

The rationale for change

Exposing hazards

The NEC changed Article 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 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. Due to the new changes in 230.71, the NEC removed the exception in the 2020 update by including transfer switches, feasible disconnect switches and others with catch-all language. Now all equipment must have a barrier on the line side.

Better personal protection

NEC 2017 changed Article 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 what I believe is an obvious safety hazard has inspired electrical professionals to look at installations more closely. Since exposed energized buses in panelboards do not have upstream OCPDs, 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 1200 amps and higher and recognizes such 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.

What might the future hold?

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 impact businesses financially. But I think resourceful contractors will find ways to meet the Code while becoming more cost-efficient.

"Technicians may need to review their designs against new requirements and will likely need to change the way they plan future projects."
Thomas Domitrovich, Eaton vice president, technical sales

Surge protection

The 2020 Change

The NEC recognizes in Article 90.1(A) that the purpose of the Code is the practical safeguarding of persons and property from hazards arising from the use of electricity. Updates to surge are twofold. First, Article 242, titled "Overvoltage Protection," does not add new requirements but rather consolidates surge requirements from around the NEC to bring attention to performance issues that align with circuit applications. Secondly, Article 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.
The rationale for change

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 table stakes and a key driver for surge protection clarification and expansion. The requirements provide for life safety products like AFCIs, GFCIs, smoke detectors and other protection devices. But I could make an argument 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. Insurance companies take the brunt of surge losses. While insurance companies don't often publish payout amounts due to proprietary information, my best guess is that it's millions of dollars. This, of course, results in higher insurance premiums paid by homeowners, something these requirement changes look to help prevent.

What might the future hold?

Not all surge devices are created equally. Devices feature different parameters, such as varied threshold voltages, but no performance-related requirement currently exists. I believe the NEC will push to mandate higher-quality products by establishing SPD performance requirements in the future.

Additionally, I feel the NEC should look to protect digital connections. For instance, we can protect the power supply for a TV, but surges also travel down data cables to cause damage. There's potential for the NEC to discuss this aspect of power protection as well.
Looking to the 2023 code review cycle

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 protections for workers and the equipment they service. As with any requirement update, feedback from professionals in the field is extraordinarily important. I look forward to seeing how technicians implement the new requirements so that we may refine the Code in 2023.

Further, I feel it's vital that everyone in the electrical field explore articles in their purview that could benefit from enhancement. Many 2020 updates were inspired by professionals who knew that more could be done to enhance safety, so I know the industry has the capacity to make proactive changes. With that, I encourage everyone in the industry to look to the requirements they know need improvement and start conversations now in preparation for the 2023 code review cycle.

Looking to the 2023 code review cycle

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 protections for workers and the equipment they service. As with any requirement update, feedback from professionals in the field is extraordinarily important. I look forward to seeing how technicians implement the new requirements so that we may refine the Code in 2023.

Further, I feel it's vital that everyone in the electrical field explore articles in their purview that could benefit from enhancement. Many 2020 updates were inspired by professionals who knew that more could be done to enhance safety, so I know the industry has the capacity to make proactive changes. With that, I encourage everyone in the industry to look to the requirements they know need improvement and start conversations now in preparation for the 2023 code review cycle.

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See the original full article at: https://www.eaton.com/us/en-us/company/news-insights/for-safetys-sake-blog/nec-2020-enhances-service-entrance-surge-protection.html

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