WWW − When and Where should Which surge protection be used?
By Dipl Ing R Hausmann, Phoenix Contact
Electricity+Control, January 2015 (pages 18 – 21)
Enquiries: Email rhausmann@phoenix contact.com
Read the full article on WWW − When and Where should Which surge protection be used? in PDF format.
IEC 61643-22 is a guide for the application of Surge Protection Devices (SPDs) to telecommunications and signalling lines. Because telecommunications and signalling systems depend on long lengths of wire, either buried or aerial, the exposure to over voltages from lightning, power line faults and power line or load switching, can be significant. If these lines are unprotected, the resultant risk to Information Technology Equipment (ITE) can also be significant.
International Standard IEC 61643-22 (prTS 61634-22) describes the principles for the selection, operation, location and coordination of SPDs connected to telecommunication and signalling networks.
When should a surge protection to be used?
The need for protective measures for IT systems should be based on a risk assessment considering the probability of overvoltage and overcurrent. The decision to install protective measures shall be assessed based on:
- Risk of damage to the network outside or inside the structure
- Tolerable risk of damage
For the structure and network inside the structure, the customer shall analyse these two values. Table 1 (see pdf) gives a general overview of the responsibility for protective measures. Annex C of IEC 61643-22 provides additional information concerning Risk Management.
- Adherence to IEC 61643-22 will prevent severe damage.
- The need for protective measures for IT systems should be based on risk assessment.
- Protection devices should be applied in a cascade arrangement at the zone interfaces.