Type 1 SPD vs Type 2

What Are Surge Protective Devices and Why Are They Important?

SPD concept: Surge Protective Device (SPD) is an electrical appliance designed to protect circuits and associated facilities from damages caused by transient overvoltages and spikes. They can provide precise protection to minimize equipment downtime and guarantee smooth operation.

Surge protective devices, often called surge arresters or surge suppressors, are designed to protect electrical installations and equipment against transient overvoltages. These sudden voltage spikes can originate from:

- Lightning strikes (direct or indirect)
- Utility grid switching operations
- Large equipment turning on or off
- Power outages and subsequent restoration
- Electrical accidents

Without proper surge protection, these transient voltage events can damage sensitive electronics, reduce equipment lifespan, cause data loss, and even create fire hazards. According to industry studies, power surges cause billions of dollars in equipment damage annually, making surge protection an essential investment for both residential and commercial applications.

When it comes to protecting your electrical equipment and systems from power surges, understanding the differences between Surge Protective Device (SPD) Type 1 and Type 2 is crucial. Each type serves a specific purpose in the electrical protection hierarchy, and choosing the right one can mean the difference between safeguarding your valuable equipment or risking costly damage.

What is a type 1 surge protector?

Type 1 surge protectors protect residential and commercial buildings from external, high-energy voltage spikes, primarily caused by lightning strikes.

Typically installed between the utility service entrance and the main distribution panel, they provide a first line of defense by intercepting power surges before they enter the building’s electrical system. This type of protector can effectively manage large surges, preventing potential damage to electrical infrastructure and connected equipment.

What is a type 2 surge protector?

Type 2 surge protectors protect appliances and sensitive electronic equipment from internal voltage spikes and surges commonly found in a building’s electrical system.

Installed in switchboards, this type of surge protector handles surges that occur from switching electrical loads or bypassing external defenses. It provides a vital second line of defense by mitigating the effects of these surges, thereby increasing the overall safety and lifespan of electrical equipment within the premises.

Differences between Type 1, Type 2 SPD surge protector

1. Waveform:

Different SPDs are categorized and rated based on specific waveforms that simulate the nature of common electrical disturbances. A waveform refers to the specific shape and characteristics of the transient voltage or current surge that the SPD is designed to withstand. Different types of SPDs are tested and rated against different waveform standards, which represent different types of potential surges. Here are some of the most common:

- 10/350 µs Waveform (Type 1 SPDs): features a rise time of 10 microseconds and a more protracted duration of 350 microseconds. The waveform is employed in defining the ratings of type 1 SPDs, specialized devices crafted to protect against direct lightning strikes. The extended rise time reflects the slower buildup of voltage typical in such lightning events.

- 8/20 µs Waveform (Type 2 SPDs): This waveform exhibits a rapid rise time of 8 microseconds and a relatively extended duration of 20 microseconds. It is a standard for defining the ratings of type 2 SPDs. The devices are engineered to protect against fast-rising, high-current surges that may arise from activities like switching operations or nearby lightning strikes. The waveform effectively replicates the swift increase in voltage associated with these events, guiding the design and performance expectations of type 2 SPDs.

2. Energy Handling Capacity:

Two types of SPDs differently in their energy handling capacity as they are designed to function against varied end-of-use scenarios, classified according to their location and protection level:

- Type 1 surge protective device (SPD), categorized as Class B, efficiently handles the highest surge currents originating from direct lightning strikes or intense high-energy events, with an energy handling capacity of Iimp (10/350 µs) 25kA to 100kA.

- Type 2 surge protective device (SPD), classified as Class C, addresses medium-sized surges more common than type 1 but still potent enough to damage electronics. With an energy handling capacity ranging from In & Imax (8/20 µs) 20kA to 110kA.

3. Performance:

- Type 1 devices are designed to protect against external surges, including direct lightning strikes, which are rare but can be very destructive.

- Type 2 devices protect against surges inside a building from large appliances turning on/off, or against external surges that pass through a Type 1 device.

Is Type 1 SPD better than Type 2?

A type 1 SPD is generally crafted to manage the high-energy surges linked with direct lightning strikes. However, type 1 arresters alone do not fully protect the electrical system. From the standpoint of energy handling capacity, they do surpass that of type 2 SPDs, whereas type 1 SPDs confront greater surge currents. Although they can endure a significant portion of the energy, there remains residual current that requires the functionality of type 2 surge arresters.

Consider a large concert venue where the main entrance is equipped with sufficient security checks (functions as a type 1 SPD) to prevent any major threats or unauthorized items from entering the venue. At the same time, inside the concert hall, there are additional security personnel and checks (similar to a type 2 SPD) to handle smaller issues to guarantee the concert is going on smoothly.

The choice between type 1 and type 2 SPDs depends on factors such as installation location and the anticipated energy currents they need to handle. It’s worth noting that neither type 1 nor type 2 SPDs are inherently superior; their effectiveness is contingent on specific application requirements.

Positions type 1 and type 2 SPDs are designed to protect

Type 1 SPDs are strategically designed to be installed at the main electrical panel and their primary function is to handle high-energy surges that originate externally.

It will be installed in the primary distribution board at the origin of the electrical installation. Type 1 surge protection device is particularly useful in a high lightning density area where the risk of heavy surge current or even direct strike is high (eg.: buildings equipped with lightning rods).

Type 1 surge protective device (SPD) can be found extensively in various applications, prominently at the main electrical panel.

On the other hand, type 2 SPDs are positioned at the sub-panel or branch circuit level within the electrical system and on the load side of the service equipment overcurrent device, including SPDs located at the branch panel. They are designed to provide protection against localized surges and moderate to high-energy transients that may still pose a threat to sensitive equipment.

By being closer to the point of use, type 2 SPDs offer a secondary layer of defense, effectively preventing surges from traveling further into the electrical network.

How to Choose the Right Surge Protective Device?

Selecting the appropriate surge protection requires consideration of several factors:

1. Risk Assessment

- Lightning Exposure: Properties in lightning-prone areas should prioritize Type 1 protection
- Equipment Value: Higher-value equipment justifies more comprehensive protection
- Critical Operations: Mission-critical systems require multi-layered protection
- Downtime Costs: Consider the cost of potential downtime from surge damage

2. Technical Considerations

- System Voltage: Match the SPD to your electrical system voltage
- Short Circuit Current Rating: Ensure the SPD can handle the available fault current
- Surge Current Capacity: Higher ratings provide better protection and longer life
- Voltage Protection Rating (VPR): Lower is better for sensitive equipment
- Modes of Protection: L-N, L-G, N-G, L-L (more complete protection includes all modes)

3. Implementation Strategy

- Type 1 SPD at the service entrance to handle the most severe surges
- Type 2 SPDs at distribution panels to protect branch circuits

Should I get both Type 1 and Type 2 SPDs?

The decision to use both type 1 and type 2 SPDs depends upon various factors. Considerations include the risk of lightning strikes in the area, the sensitivity of the electronic equipment being used, budget plans, and adherence to local electrical codes and regulations.

In situations where the risk of lightning is high or where critical and sensitive equipment is in use, the installation of both types of SPDs is often recommended.

Type 1 surge arresters are required to be installed directly under the incoming breaker, especially when there is a lightning rod on the building roof.

For industrial and commercial sites, it is a must to have both surge arresters installed in place as lightning protection to these areas dense in popularity comes more urgent, the lack of protection could not only bring in equipment and facility damage but potentially extend to putting the safety of people at risk.

Consulting with a qualified electrician or electrical engineer is necessary to assessing the specific needs of the electrical system and determining the most effective combination of SPDs for sustained protection.

Installation Best Practices

Proper installation is crucial for effective surge protection:

1. Important notes before installing

- Make sure power at the circuit breakers or disconnect switches is disconnected.

- The installation and wiring procedures must adhere to both national and local electrical standards.

- Qualified licensed technicians or electricians should be responsible for the installation and servicing of the system.

- The conductor lengths should be as short and straight as possible for best performance.

- Avoid coiling excess wire. Avoid coiling excess leads.

- Avoid 90 degrees bend and bend wires as rounded for the best performance.

- Cut all leads to the correct length.

- The conductors for the SPD installation are preferably not exceed 0.5 meters and, under no circumstances, surpass 1 meter.

2. Type 1 SPD Installation

- Install as close as possible to the service entrance
- Use short, straight conductor leads (less than 12 inches if possible)
- Use appropriate wire size (typically 6 AWG or larger)
- Ensure proper grounding connection
- Follow manufacturer’s torque specifications

3. Type 2 SPD Installation

- Install on load side of main breaker
- Position close to the protected equipment or panel
- Minimize lead length to reduce impedance
- Use dedicated breaker per manufacturer specifications
- Install in a location accessible for periodic inspection

Maintenance and Replacement Considerations

Surge protective devices don’t last forever and require periodic attention:

- Regular Inspection: Check indicator lights (if available) monthly
- Lifespan: Most SPDs have a finite lifespan and degrade with each surge event
- Replacement Triggers: Replace after major surge events, when indicators show end-of-life, or per manufacturer’s recommended schedule
- Documentation: Keep records of installation dates and any surge events
- Testing: Consider periodic testing by qualified electricians for critical installations

Regulatory Standards and Compliance

When selecting surge protective devices, look for products that comply with relevant standards:

- UL 1449 4th Edition: The primary standard for surge protective devices in North America
- IEEE C62.41: Defines surge environments and testing procedures
- NFPA 70 (National Electrical Code): Contains requirements for SPD installation
- IEC 61643: International standard for low-voltage surge protective devices

Compliance with these standards ensures that the devices have been tested and verified to provide the protection they claim.

Common Misconceptions About Surge Protection

To help you make informed decisions, let’s address some common misunderstandings:

- Misconception: A single surge protector is sufficient for whole-building protection.
  Reality: A coordinated approach with multiple types provides the most comprehensive protection.

- Misconception: All surge protectors provide equal protection.
  Reality: Protection levels vary significantly between Types 1, 2, and 3, and even between models within each type.

- Misconception: Surge protectors last forever.
  Reality: They degrade with each surge event and require periodic replacement.

- Misconception: Surge protectors protect against all power problems.
  Reality: They protect against transient surges but not against sustained overvoltages, undervoltages, or outages.

Conclusion

In summary, the main differences between Type 1 and Type 2 surge protectors are their location and the nature of the surges they are designed to combat. Understanding these differences can help us choose the right surge protection strategy to ensure the life and reliability of electrical installations and sensitive equipment.

While Type 1 surge arresters serve as the primary defense against powerful external surges like lightning strikes, Type 2 spds provide essential protection against the more frequent internal transient overvoltages generated within your electrical installation. Often, the most robust and reliable protection is achieved through a coordinated approach that utilizes both types of spd in a layered configuration. This provides comprehensive surge protection from the secondary of the service transformer down to the point of use.