A surge protection device (also called SPD) is a component of the electrical installation protection system.
This device is connected in parallel on the power supply circuit of the loads that it must protect, but it can also be used at all levels of the power supply network.
This is the most commonly used and most efficient type of overvoltage protection.
SPD is designed to limit transient overvoltage (coming from atmospheric origin or switching surges due to network operations) and evacuate the peak voltage to earth, to limit the amplitude of this overvoltage to a value that is not hazardous for the electrical installation.
Today, standards define three types of SPD for low voltage electrical installations: Type 1, Type 2 & Type 3 SPDs.
Depending on the environment and on the current and voltage waves, you might use some of those types.
• Type 1 SPD, such as our range Acti9 iPRD1, PRD1
This device is connected in parallel on the power supply circuit of the loads that it must protect, but it can also be used at all levels of the power supply network.
This is the most commonly used and most efficient type of overvoltage protection.
SPD is designed to limit transient overvoltage (coming from atmospheric origin or switching surges due to network operations) and evacuate the peak voltage to earth, to limit the amplitude of this overvoltage to a value that is not hazardous for the electrical installation.
Today, standards define three types of SPD for low voltage electrical installations: Type 1, Type 2 & Type 3 SPDs.
Depending on the environment and on the current and voltage waves, you might use some of those types.
• Type 1 SPD, such as our range Acti9 iPRD1, PRD1
To be used if building with lightning rod (or distance ≤ 50m). Prevents 90% of destructive lightning currents from entering the electrical installation of a building, but with low voltage protection level (Up). Type 1 must be completed by Type 2.
• Type 2 SPD, such as our ranges Acti9 iQuick-PF, iQuick-PRD or Acti9 iPRD To complete Type 1. Diverts 99% of lightning current flow and ensures good voltage protection level (Up).
• Type 3 SPD, such as our range Acti9 iPRD To complete Type 2. Provides very good voltage protection level, but with very low discharge capacity. It must be installed in the vicinity (d2 < 10 m *) of sensitive loads (Up ≤ 1500V) and it cannot be used alone with Type 1.
Finally, the lightning arrester's associated disconnecting device (circuit breaker or fuse) will be determined according to the short-circuit current at the installation site. Manufacturers provide a coordination table between the surge arrester and the associated disconnecting device. You'll find this table in our Design Guide.
Released for:Schneider Electric Belgium
