Electrical Surge Protection

By R.W. Hurst, Editor

Electrical surge protection is a system designed to protect electronic devices from voltage spikes caused by various factors, such as lightning strikes, power line faults, or electrical equipment switching. These sudden increases in voltage can damage or destroy connected devices, leading to expensive repairs or replacements. Therefore, the importance of electrical surge protection cannot be overstated, as it helps maintain the integrity of electrical systems and safeguards investments in electronic equipment.


A surge suppressor is at the heart of electrical surge protection. They limit the voltage supplied to an electronic device by blocking or shorting the unwanted voltage from neutral to ground or line to ground. Some surge protectors, such as the metal oxide varistor (MOV), react to the excess voltage by diverting it away from sensitive components. In contrast, others, like the uninterruptible power supply (UPS), provide continuous power even during voltage fluctuations, ensuring that connected devices remain operational.

Although surge protectors and power strips may appear similar, there is a crucial difference between them. Power strips primarily function as extension cords, providing multiple outlets for plugging in devices. While some power strips may offer basic surge protection, more is needed to protect against significant voltage spikes. On the other hand, surge protectors are specifically designed to guard against harmful voltage fluctuations, providing higher protection for connected devices.

Choosing the right surge protector for your home or office requires consideration of several factors. First, identify the type of devices to be protected and their power requirements. For industrial and commercial applications, consider investing in a whole-house surge protector or a surge protection device (SPD) installed at the service entrance to shield the entire facility. Additionally, ensure that the surge protector meets industry standards and offers adequate joule rating, response time, and clamping voltage to provide optimal protection.

When selecting a high-quality surge protector, look for the following key features:

  • A high joule rating indicates the surge protector's energy-absorbing capacity.
  • A low clamping voltage determines the voltage level at which the protector starts to divert excess voltage.
  • Fast response time ensures the protector reacts quickly to voltage spikes.
  • UL certification, confirming that the product has been tested and meets safety standards.
  • Indicator lights, which signal if the protector is functioning correctly and if the connected devices are grounded.

Regular replacement of surge protectors is essential for maintaining their effectiveness. However, over time, the components within a surge protector can degrade, reducing its ability to protect against surges. Therefore, replacing surge protectors every three to five years or following a significant power surge or lightning strike is generally recommended.

While surge protectors can offer protection against many voltage fluctuations, it is essential to note that they may not provide complete protection against direct lightning strikes. Therefore, a comprehensive lightning protection system, including grounding and bonding, must safeguard electrical systems and structures from severe lightning-induced damage.

Electrical surge protection plays a vital role in preserving the integrity of industrial, commercial, and institutional power systems and protecting valuable electronic devices from potential damage. By understanding the importance of surge protection, selecting the appropriate surge protectors, and ensuring their regular replacement, facilities can minimize the risks associated with power surges and safeguard their investments in technology.


What are the three different types of surge protectors?

There are various types of surge protectors, but they can generally be categorized into three main types:

  1. Primary (Type 1) Surge Protectors: These surge protectors are installed at the main service entrance or utility meter of a building. They protect against high-energy voltage surges, such as those caused by direct lightning strikes, and are designed to handle large amounts of energy. Type 1 surge protectors are typically used in industrial and commercial facilities with a high risk of lightning strikes.

  2. Secondary (Type 2) Surge Protectors: Type 2 surge protectors, also known as point-of-use surge protectors, are the most common type found in homes and offices. They are installed at the electrical panel, subpanel, or power outlet to protect individual or group devices. In addition, secondary surge protectors safeguard against voltage spikes from within the building, such as those caused by switching electrical loads or faulty wiring. These surge protectors typically include power strips with built-in surge protection, standalone surge protectors, or whole-house surge protectors connected to the electrical panel.

  3. Power Line Conditioners (Type 3) Surge Protectors: Power line conditioners, also known as voltage regulators or uninterruptible power supplies (UPS), protect devices from voltage surges and help maintain a stable voltage level. They are designed to correct voltage fluctuations, ensuring connected devices receive a consistent and clean power supply. Power line conditioners are commonly used with sensitive electronic equipment, such as computers, servers, and medical devices, where stable power is crucial for proper functioning and data integrity.

Each type of surge protector has its specific use case and provides varying levels of protection. Therefore, choosing the right type is essential because of your particular needs and the devices you want to protect.