Electrical surges are undesirable situations in which the actual voltage briefly exceeds the electrical voltage limit for which an electrical system was designed.
These can cause various types of damage: data loss, outages, fusion of conductors, breakage or destruction of equipment, up to fires.

Now let's see what are the causes of overvoltages and how to make your electrican home and work equipment safe.

Image of  Overvoltage causes


  • Lightning (direct and indirect);
  • Large inductive loads connected to the network: industrial, commercial or air conditioning systems;
  • Disconnection and restoration of power to the grid due to maintenance work carried out on the power distribution system;
  • The switching on and off of these plants cause dangerous surges of transient pulses that can get into the electrical distribution network, reaching even domestic appliances.


  • Common mode: occur between the live cable (L) and the earth. So the appliances with earth connection are the more at risk; 
  • Differential mode: occur between the active cables, L/L or L/N. In this case all the appliances without earth connection (like PC, telephone chargers, all the Class II devices) are the more at risk.
Image of  Surge Protection Devices


Surge protectors are devices that protect power lines by absorbing voltage variations in place of special equipment. There are high voltage surge arrester and SPD Surge Protection Device (for low tension systems).

  • Type 1 (T1):  suitable for areas often affected by thunderstorms with high risk of direct lightning, especially if there is no external lightning protection system in the building.
    Suggested installation: close to the mains switch from the mains provider.
  • Type 2 (T2): not suitable to protect against direct lightning, but they can be used to filter out overvoltage and overcurrent caused by an indirect lightning; they can also be used where several maintenance work are performed in the mains distribution network.
    Suggested installation: within the main switch board and the secondary switch boards along the domestic system.
  • Type 3 (T3): useful to add an extra protection to electrical appliances already covered with Type 1 or Type 2 SPD.
    Suggested installation: nearby the device to protect, especially when the cable run from the switch board is longer than 10 meters.
Image of  Scorpio


Scorpio is a differential surge protector (SPD) designed specifically for low voltage that protects against direct and indirect effects of lightning or other transient overvoltages. To be installed before the device to protect.

Available in 4 models:

  • 2kA 4kV (cod. SRG-S000-240-01)
  • 3kA 6kV (cod. SRG-S001-240-01)
  • 5kA 10kV DIN (cod. SRG7XCB2)
  • 5kA10kV BOX (cod. SRG7XCBD)

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