SPD application example in Supermarket

Fig. J45 – Application example: supermarket

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 10m 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 10m 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 iC60 disconnection circuit breaker rated at 40 A.
• Install fine protection surge arresters, Imax = 8 kA (8/20 µs) and the associated iC60 disconnection circuit breakers rated at 10 A

Fig. J46 – Telecommunications network