The differences between Type 1, Type 2, and Type 3 SPDs can be distinguished in four aspects, namely installation location, protection objectives, surge protection capabilities, and application scenarios.
Installation location: Type 1 SPD is installed at the power supply entrance of the electrical system, close to the main circuit breaker, to prevent severe external large surges. Type 2 SPD is installed in the distribution board as a second layer of protection for the electrical system, blocking secondary surges generated by Type 1 SPDs that are not completely intercepted, and can also block internal surges. Type 3 SPD is installed near the terminal equipment to provide more detailed low-level surge protection for the equipment that needs to be protected.
Protection Goal: Type 1 SPD protects the entire building’s electrical system from external large surges (lightning strikes). Type 2 SPD is used to block internal surges (operating overvoltage caused by human operations, electrical equipment switches, etc.), while Type 1 SPD does not completely block secondary surges caused by large surges. Type 3 SPD focuses on protecting a single or a small group of end devices.
Surge Protection Capability: Type 1 SPD can withstand very high surge currents and protect equipment from large surges such as lightning strikes. Type 2 SPD is suitable for handling most surges and has wide applicability. Its protection capability is between Type 1 SPD and Type 3 SPD. Type 3 SPD is used to handle low-level surges and provide more detailed protection for end equipment.
Application Scenarios: Type 1 SPD is used in industrial facilities and commercial buildings as well as some large electrical systems to prevent risks caused by large surges such as lightning strikes. Type 2 SPD is widely used and is the most common type of surge protector. Type 3 SPD is used in niche and small situations, focusing on protecting a single or a small group of sensitive and high-value devices.
These three types of SPDs need to be used together in practical applications to provide comprehensive protection for the electrical system through different functions and protection levels.
Feature | Type 1 SPD | Type 2 SPD | Type 3 SPD |
Where It’s Installed | At the entry point of your home/building’s electricity, like the main entrance | On the electrical panel, like the power distribution center of your home | Right next to or directly plugged into appliances, like beside your TV and computer |
Why Use It | Protects your whole house when lightning strikes directly or nearby | Deals with smaller surges that sneak in from outside, protecting home appliances | Blocks the last bit of small surges, protecting close-to-heart electronics |
How Big a Surge It Can Handle | Can block super big surges, like a superhero in movies | Medium strength, can block most surges under normal conditions | Specifically for small surges, protecting sensitive electronic devices |
Ideal For | Places that might get directly hit by lightning, like skyscrapers or factories | Almost every home, shop, and factory needs one | Protecting pricey electronics like computers and TVs |