Commercial Surge Protection

Commercial Surge Protection

Created by: Glen Zhu | Updated Date: August 31st, 2023

Do Commercial Buildings Need Surge Protection?

Electronic devices are the backbone of efficiency and connectivity for businesses and homes alike in our fast-paced modern world. From smart appliances to complicated industrial setups, our reliance on sensitive electronics is incomparable. However, this dependency exposes us to a persistent threat of power surges. These sudden and intense voltage spike, originates from lightning strikes, utility fluctuations, or equipment malfunctions, can swiftly disrupt operations and damage valuable equipment.

The ultimate solution to fortify your electronics against the harmful effects of power surges is Surge Protection Devices (SPDs).

Engineered to redirect excess electrical energy away from delicate devices, SPDs act as steadfast guards, preserving the functionality and longevity of your electronics. SPDs are the cornerstone of protection which assure uninterrupted operations and data integrity across commercial and residential environment by providing a steady defense against the catastrophic consequences of power surges.

In this description, we will delve into a realm of surge protection devices – unveiling their significance, mechanisms, diverse variants, and versatile applications.

Whether you’re a homeowner seeking to shield your domestic technology or a discerning professional entrusted with upholding crucial infrastructure, comprehending the essence and advantages of surge protection devices is paramount.

Join us in this study as we decode the intricacies of surge protection, equipping you with the insights needed to mitigate the perils posed by power surges and fortify your electronic investments.

SPD protect your commercial buildings & Electronics

1. What is Commercial Surge Protection Device?

A commercial surge protector, a commercial-grade surge suppressor or surge protection device (SPD), is a specialized electrical device designed to safeguard sensitive electronic equipment and systems in commercial buildings from voltage spikes and surges. These voltage fluctuations can result from various sources, including utility switching, lighting strikes, or equipment operation, and they have the potential to cause damage, data loss, and downtime to critical electronics.

Commercial surge protection provide a higher level of protection compared to standard residential surge protectors. They can handle larger electrical loads and more robust surge events commonly occuring in commercial environments having number of electronic equipments such as computers, servers, networking devices, telecommunications systems, industrial machinery, and more.

2. Features of Commercial Surge Protectors

Key features of commercial surge protectors include

(1) Voltage Regulation: They often incorporate voltage regulation mechanisms to maintain a consistent voltage level during power fluctuations.

(2) Surge Handling Capacity: These devices divert excess energy away from sensitive equipment.

(3) Multiple Protection Levels: Commercial surge protectors typically provide layers of protection, including protection against voltage spikes on power lines, data lines (such as Ethernet or phone lines), and other communication lines.

(4) Mounting Options: They come in various form factors and mounting options suitable for commercial setups, including rack-mounted surge protectors for server rooms and wall-mounted units for office spaces.

3. Commercial Surge Protectors for Commercial Buildings

Surge protection for commercial buildings relies on strategic locations of SPDs at critical points within the electrical distribution system. These devices divert surge currents from sensitive equipment, preventing damage and ensuring operational continuity. Following are the key features of surge protection for commercial buildings.

3.1  Categorization of Protection Zones in Commercial Buildings

The surge protection in commercial buildings divides into protection zones based on the potential sources of surges and the criticality of the equipment. This categorization determines the type and placement of SPDs to provide varying levels of protection against transient overvoltages or surges. These categories are in international standards like IEC 61643-11 for AC systems and IEC 61643-31 for DC systems, and summary of various types is in the table below.

Point / SPD Type

Type 1 SPD

Type 2 SPD

Type 3 SPD

Category of Class

Class I

Class II

Class III

Type of Protection





Main Distribution Panel


Near Equipment to be protected

Potential Source of Surge

Lightning Strikes

Power Grid Disturbances and Equipment Switching

Voltage Fluctuations

Voltage Handling Capacity




Impulse Current Rating




In summary, Type 1, Type 2, and Type 3 surge protection devices provide a layered approach to mitigating transient overvoltages. Type 1 devices provide primary protection against severe surges, Type 2 devices offer intermediate protection against common surges, and Type 3 devices provide localized protection for sensitive equipment. Proper coordination and installation of these SPD types by following standards and regulations help ensure comprehensive surge protection for electrical and electronic systems.

3.2 Coordinated Surge Protection for Commercial Buildings

Surge protection is implemented in a coordinated manner, starting from the external service entrance while extending to internal distribution panels and sensitive equipment. 

This layered approach ensures that surges are suppressed at multiple levels, minimizing their impact.

3.3 Proper Grounding & Bonding of Surge Protection in Commercial Buildings

Surge protection requires proper grounding and bonding practices to ensure effective dissipation of surge current and prevent ground potential rise, which can lead to safety hazards.

3.4 Maintenance and Testing

Regular inspection, maintenance, and testing of surge protection devices are essential to ensure their continued functionality. Degradation over time can compromise the effectiveness of SPDs.

4. General Types of Commercial Surge Protection Devices

The various types of commercial surge protection solutions fulfill specific needs within commercial buildings. Each of the types of surge protection devices (SPDs) for commercial applications is in detail:

4.1  Whole-Building Surge Protectors

Whole Building surge protectors, are installed at the entry point of electrical supply in the commercial buildings. These are also known as service entrance surge protectors, which protect against large-scale surges entering the building’s electrical system through the main power lines. Electrical surge protectors for commercial buildings safeguard the facility’s electrical infrastructure, including all connected devices and systems.

4.2 Panel-Mount Surge Protectors

These are also known as service entrance surge protectors installed at the main electrical panel of a commercial building. They protect against large-scale surges that enter the building’s electrical system through the utility lines. Whole-building surge protectors safeguard the entire facility’s electrical infrastructure, including all connected devices and systems.

4.3  Rack-Mount Surge Protectors

These surge protection devices are for data centers and server rooms, and installed within server racks. They protect networking equipment, servers, and all other data center gears against surges initiated from power and data lines. Rack-mounted surge protection devices are compact and fit seamlessly into standard rack units.

4.4 Point-of-Use Surge Protectors

Point-of-use surge protectors are plugged directly into electrical outlets, protecting individual devices or equipment. These are versatile and suitable for protecting sensitive electronics such as computers, monitors, printers, and other office equipment.

4.5 Data Line Surge Protectors

Data Line Surge devices protect communication and data lines from voltage spikes.

They contain surge protection for Ethernet cables, telephone lines, coaxial cables, and other communication interfaces.

4.6 Transient Voltage Suppressors (TVS)

TVS devices protect specific components or subsystems within electronic equipment. They are often engaged on printed circuit boards to safeguard sensitive electronic components from transient voltage spikes.

5. Compliance of Surge Protection in Commercial Buildings with NEC

Surge protection in commercial buildings is critical to safeguard electrical and electronic equipment from transient overvoltages or surges. The National Electrical Code (NEC) provides guidelines and requirements for surge protection systems in commercial buildings to enhance safety and minimize equipment damage. The NEC offers guidance on the implementation of surge protection.

5.1 NEC Article 280: Surge Arresters, Over 1000 Volts

This article covers surge arresters usage for systems with voltages over 1000 Volts. This article does not apply to surge protection for commercial buildings as they deal with low voltages below 1000 volts in the case of AC or DC power systems.

5.2 Surge Protection, 1000 Volts or Less

Article 285 of NEC is related to surge protection for commercial buildings as it focuses on voltages below 1000 volts. The NEC compliance of surge protection in commercial buildings is in detail.

5.2.1 Service Entrance Surge Protection

NEC 285.22 requires the installation of Type 1 SPD on the supply side of the service disconnect in locations with a high risk of lightning strikes. This article helps to stop lightning-induced surges from entering the building’s electrical scheme.

5.2.2 Coordination with Service Equipment and Grounding

NEC 285.23 emphasizes the importance of proper coordination between surge protection devices, grounding, and service equipment. This coordination ensures effective surge current diversion and protection.

5.2.3 Service Equipment Rating and Surge Current

NEC 285.24 summarizes requirements for the rating and surge current withstand capability of surge protection devices installed at the service entrance. This article guarantees that the SPD can handle the expected surge in current levels in the specific application.

5.2.4 SPD Installation and Labeling

NEC 285.25 provides installation guidelines for SPDs, including proper grounding and conductor sizing. Surge protection devices must be labeled to indicate their intended purpose and connection points.

5.3 Surge Protection Device for Dwelling Units

The requirement of surge protection devices for dwelling units of single occupancy and multiple units is in NEC 230.67(A). Type 1 or Type 2 surge protective device (SPD) is required integral to or adjacent to the electrical service.

5.4 Surge Protection with Emergency System Loads

Surge protection with emergency system loads is considered necessary according to NEC 620.51(E). This article entails the utilization of surge protection with emergency system loads such as elevators, escalators, chairlifts, moving chairlifts, and associated equipment.

5.5 Surge Protection for Critical Data Systems

Critical Operation Data Systems (COPS) is defined as “Information technology equipment systems that require continuous operation for public safety, emergency management, national security or business stability. Article 645.18 of NEC says the provision of Surge protection for Critical Operations Data Systems.

5.6  Surge Protection for Industrial Machinery

Surge protection for industrial machinery is necessary in case of failure of safety interlocks on machinery, causing safety risks to operators who may not be aware of disabled safety mechanisms. Article 670.6 of NEC tells us to install surge protection with industrial machinery.

5.7  Surge Protection with Fire Pump Controller

the article 695.15 of NEC tells us about installation of surge protection with a Fire Pump controller. A SPD is necessary to protect the fire pump controller. Fire Protection Research Foundation established that 12% of surveyed had damage in fire pumps due to surges.

5.8 Surge Protection with Emergency Switchboards & Panel Boards

Commercial buildings have a variety of power systems in operations whose safety and proper function is the most crucial requirement.

The article 700.8 of the National Electric Code highlights the installation of surge protection in all emergency switchboards and panel boards.

The Emergency power systems require power for designated loads upon loss of a normal-power supply. This requirement ensures a reliable power supply to vital loads in damaging surges or spikes.

5.9 Surge Protection with All Voltage Distribution Levels

The provision of surge protection devices with all voltage distribution levels shall be ensured for COPS as stated in NEC 708.20 article. COPS contain HVAC systems, fire alarms, safety, communications, and signaling for designated critical operations areas. The surge protection for these will ensure the operation of these systems in an emergency.

6. How does Commercial Surge Protection Work?

Surge protection devices (SPDs) work based on diverting and dissipating transient overvoltages or surges away from sensitive electrical and electronic equipment. The primary goal is to prevent these surges from damaging or disrupting connected equipment. The working principle of commercial surge protection includes the following five steps.

6.1 Surge Detection

The occurrence of a voltage surge in the electrical system causes a sudden rise in the voltage level leading to an influx of excessive electrical energy that can overwhelm and damage connected devices.

6.2 Voltage Clamping

Surge protection devices are designed with specialized components, such as metal oxide varistors (MOVs) or gas discharge tubes (GDTs), having nonlinear voltage-current characteristics. When the voltage across these components exceeds a certain threshold (known as the clamping voltage), they rapidly switch from a high-resistance state to a low-resistance state. This action essentially “clamps” the voltage surge by providing a low-impedance path for the excess energy.

6.3 Diverting Excess Energy

As the surge protection device clamps the voltage surge, it diverts the excess energy away from the connected equipment. It prevents the voltage spike from reaching and damaging sensitive electronics.

6.4 Dissipation of Energy

The surge protection device absorbs the superfluous energy and scatters it as heat. This heat is dissipated and dispersed through the device’s internal components and external heat sinks.

6.5 Recovery

After the surge event subsides and the voltage returns to normal levels, the surge protection device gradually returns to its high-resistance state. Thus, ensuring that the device is ready to respond to subsequent surge events.

7. Types of Surge Protection Devices

Surge protection devices safeguard electronic equipment and systems from voltage spikes and surges in either AC or DC power systems. The distinction between AC and DC surge protection is necessary because these two types have unique characteristics that require specialized protection measures.

7.1 AC Surge Protection in Commercial Buildings

AC surge protection devices safeguard equipment connected to alternating current power sources commonly used in residential, commercial, and industrial applications. These devices are installed in electrical panels, distribution points, or point-of-use locations to prevent voltage spikes caused by lightning strikes, utility switching, or other power disturbances from damaging connected equipment.

The Key features of AC surge protection are:

  • Protection against voltage surges on AC power lines.
  • Whole-building surge protection for main service entrances.
  • Panel-mount surge protectors for localized protection.
  • Range of voltage ratings to match the specific power system requirements.
  • Various form factors, including modular units and DIN rail-mountable devices.
  • Indicators for surge protection status and device health

7.2 DC Surge Protection in Commercial Buildings

DC surge protection devices are for direct current power systems having applications such as solar power systems, telecommunications, transportation (electric vehicles), and industrial automation. A DC surge protection devices protect sensitive electronics from voltage spikes due to lightning, system switching, or other disturbances in DC power systems.

The Key features of DC surge protection include:

  • Protection against voltage surges on DC power lines.
  • Tailored voltage ratings to match the system’s DC voltage level.
  • Wide range of applications, from solar panels to industrial control systems.
  • Specialized connectors and mounting options for various DC systems.
  • Compatibility with multiple DC voltage levels and polarities.
  • Integration with other system components, such as inverters and batteries.

8. Benefits of Surge Protection in Commercial Buildings

A commercial surge protector is a specialized device tailored to the needs of commercial buildings, contributing enhanced protection and resilience against power surges. The Surge protection in commercial buildings prevents equipment damage and contributes to business continuity, cost savings, safety, and reputation management. It is an integral part of maintaining the efficiency and reliability of modern commercial infrastructures.

Commercial surge protection offers several benefits, including:

  • Equipment Protection: Surge protection in commercial buildings preserves equipment lifespan and functionality. This device also safeguards sensitive electrical and electronic equipment such as computers, communication systems, HVAC Controls, and industrial machinery, thus reducing costly equipment failures and downtime.


  • Operational Continuity: The downtime in electric utility can disrupt the regular functioning of various parts of commercial buildings. The surge protection ensures the reduction of downtime and operational disruptions.


  • Data Preservation: Most commercial buildings house critical data centers and server rooms. A unwanted voltage surge can destroy stored data leading to potential legal and financial loss. Surge protection in commercial buildings also minimizes data loss and associated risks.


  • Cost Savings: Repairing and replacing damaged equipment is expensive. Therefore, surge protection in commercial buildings is the effective investment in terms of cost savings.


  • Regulatory Compliance: Surge Protection is mandatory for some setups that are a part of commercial buildings. The compliance of surge protection with regulatory standards and insurance requirements is critical to avoid penalties and reputation.


  • Safety & Reliability: Surge protection systems contribute to a safer working environment by reducing electrical fires or safety risks. It enhances the overall resilience of the commercial building’s electrical system, being free from external and internal disturbances.

9. Conclusion

The requirement for surge protection in commercial buildings is not just a practical choice but a strategic investment in safety, reliability, and longevity of electrical system. At one hand,the dependency of  modern businesses on sensitive electronic devices and data has significantly increased. But, on the other hand we can not ignored the potential risks caused by electric surges. The Surge protection goes beyond mere the compliance; it is a commitment to uninterrupted operations, data integrity, and safeguarding valuable assets.

By implementing a comprehensive surge protection strategy, Type 1, Type 2, and Type 3 surge protective devices, commercial buildings can fortify their infrastructure against unpredictable forces of nature and the intricacies of the power grid. This strategy mitigates the financial burden of equipment replacement and downtime and instills confidence in clients, employees, and stakeholders who rely on the uninterrupted functioning of critical systems.

Surge protection in commercial buildings is a strong pillar of resilience in a rapidly evolving business landscape, where technological advancements are both a benefit and a potential liability. It is the shield against hidden threats that can disrupt operations, compromise data integrity, and tarnish a business’s reputation. By prioritizing surge protection, the commercial buildings signal their commitment to innovation, sustainability, and operational excellence. In an interconnected world, surge protection is a non-negotiable necessity for commercial buildings that aspire to thrive amidst challenges and uncertainty.

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