SPD application example in Supermarket

Installation examples

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Fig. J43: Application example: supermarket

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Solutions and schematic diagram

The surge arrester selection guide has made it possible to determine the precise value of the surge arrester at the incoming end of the installation and that of the associated disconnection circuit breaker.

• As the sensitive devices (Uimp < 1.5 kV) are located more than 30 m from the incoming protection device, the fine protection surge arresters must be installed as close as possible to the loads.
• To ensure better continuity of service for cold room areas:

  - "si" type residual current circuit breakers will be used to avoid nuisance tripping caused by the rise in earth potential as the lightning
     wave passes through. 

• For protection against atmospheric overvoltages:

  - install a surge arrester in the main switchboard
  - install a fine protection surge arrester in each switchboard (1 and 2) supplying the sensitive devices situated more than 30 m from the
    incoming surge arrester
  - install a surge arrester on the telecommunications network to protect the devices supplied, for example fire alarms, modems,
    telephones, faxes.

Cabling recommendations 

• Ensure the equipotentiality of the earth terminations of the building.
• Reduce the looped power supply cable areas.

Installation recommendations

• Install a surge arrester,Imax = 40 kA (8/20 µs) and a C60 disconnection circuit breaker rated at 20 A.
• Install fine protection surge arresters, Imax = 8 kA (8/20 µs) and the associated C60 disconnection circuit breakers rated at 20

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Fig. J44: Telecommunications network