Surge Protection device & solutions

Surge Protection Device (SPD) Installation Stages

A Surge Protector need to be installed with a. Power lines : Placed in parallel with main incomer of distribution and sub distribution cables. LT Service Entrance conductor.
LT sub distribution board.
b. "Point of Use" Protection: PPlaced in series with the source of the over voltage Surge, and nearer to the equipment. RF Surge Protection Device
Data / Networks Surge Protection Device
Telephone Lines Surge Protection Device
CCTV (security monitoring system)

The transient voltage surges are broadly classified into two types i.e.: Lightning Surges
Switching surges

Surge Protection Device (SPD) for Power lines

Type I / Class B SPDs (10/350 Ás lightning current arrestor, which can withstand direct lightning) Type II / Class C SPDs (8/20 Ás surge arrestor, to protect against induced surge current) Combination of Type I + II / Class B + Class C SPDs (protect against both lightning + switching surges)

L T Power distribution system


Both the Lightning and the switching surges can come from outside of our power system and hence need to be isolated at the main incomer level itself.

Mode of Protection:
Depends on the configuration of the electrical distribution system, surge can be transmitted in, Common Mode:
Perturbation between an active conductor and earth, line-to-ground (L-G) or neutral-to-ground (N-G). Differential Mode:
Perturbation between active conductors, line-to-neutral (L-N), line-to-line (L-L).

Comprehensive and state of the art LT power line surge protection system salient features are:

  • Combined (Class B & C) protectionThis enables protection against both lightning and switching surges originating from outside our power system to be isolated at the main incomer level itself.
  • ConfigurationCommon mode and Differential mode transient protector.
  • Status indicator flag (local indication)Since any SPD for the power supply line is always connected in parallel to the circuit, the status indication is very essential. The modules provide status indication for both Class B and Class C characteristics.
  • Potential free contacts for Remote indicationIn addition to a local indicator flag, the unit also offers potential free contacts using which any form of audio visual alarm / automation can be configured.
  • Multiple levels of redundancyThis feature ensures that the SPD system is virtually fail safe. The modules provide for 2 levels of redundancy in each phase wherein if any element of an SPD fuses due to a major surge, that element alone will be disconnected from the circuit while the balance elements remain in the circuit and continue to provide the required protection.
  • LED IndicatorsFor visual inspection of surge occurring in the circuit to which an SPD is connected, an SPD is equipped with LED indicators for indication of the occurrence of surge.
  • Easy ReplacementModularization DIN rail design, convenient for installation and replacement

"Point of Use" Protection


Type III (Class D) SPDs (8/20 Ás surge arrestor, to protect against induced surge current)
Class D (Type III) Surge Protectors provided at the end equipment. This alone will not give continuous protection to which it is meant to give protection, since they are provided at the tail end of the system. RF signal Surge Protection Device
RF Signal receiver or emitter use to be located at higher points. They are normally the first object in the way of the lightning strike. The protection unit installed in series with the device to be protected, with coaxial cable. Data / Networks Surge Protection Device
Protect input electronic circuits of Network Cards against various damages caused by Surges. Generally, these protection devices are installed nearer to the input signal port to the device to be protected. Scope of protection: Modems, Routers, Connected Computers. Telephone Lines Surge Protection Device
The sensitive electronics equipment connected via PP, DSL or PSNT and ISDN Telephone networks should be protected as they are very sensitive and its operating voltage is very low. This series connected device can easily be couple with under protected device connection cable. CCTV (security monitoring system)
These 24 x 7 surveillances praises remote unit to be on line for notify any security threat. Continuous operation of this system may hamper / go down, affected by inductive lightning surge thorough power and control cables.