1. International Telecommunication Union Technical Session on Home Networks Geneva, 29/04/2011 ITU-T Study Group 5 Protection against Lightning Phil Day Australia

2. ITU-T Study Group 5 Introduction o This presentation is about the protection of Home Network (HN) equipment and will specifically cover: Protection parts Philosophy of protection Classification of ports Mechanisms of damage Risk 2 29.04.2011 Technical Session - Home Networks - Geneva

3. ITU-T Study Group 5 Introduction (cont) Standards Conclusion 3 29.04.2011 Technical Session - Home Networks - Geneva

4. ITU-T Study Group 5 Protection parts o Protection of an installation may require a combination of: Lightning protection of the building. Resistibility of equipment. Protection of incoming lines. Earthing and bonding of the installation. 4 29.04.2011 Technical Session - Home Networks - Geneva

5. ITU-T Study Group 5 Protection parts 5 29.04.2011 Technical Session - Home Networks - Geneva equipment a.c. mains SPD metallic water pipe earth electrodes LPS main earthing terminal Telecommunication cable Figure 1 SPD

6. ITU-T Study Group 5 Protection parts o Protection of the building structure: Protection of the building structure, if necessary, is installed according to the IEC 62305 series. It includes a Lightning Protection System (LPS) comprising air terminals, downconductors, equipotential bonding conductors and earth terminations. 6 29.04.2011 Technical Session - Home Networks - Geneva

7. ITU-T Study Group 5 Protection parts o Resistibility requirements are in Recommendation K.21: inherent and coordination requirement for external ports. inherent requirement for internal ports. basic requirement for general use. enhanced requirement for specific reasons. 7 29.04.2011 Technical Session - Home Networks - Geneva

8. ITU-T Study Group 5 Protection parts Special requirements where earthing and bonding cannot be achieved. 8 29.04.2011 Technical Session - Home Networks - Geneva

9. ITU-T Study Group 5 Protection parts o Protection of incoming lines and equipment: Installation of primary protection on external lines; mains and external telecommunication or data lines as required. Installation of protection at the equipment as required. 9 29.04.2011 Technical Session - Home Networks - Geneva

10. ITU-T Study Group 5 Protection parts o Earthing and bonding Earthing is the connection of the earth bar to earth, usually via an installed earth electrode. Bonding is the interconnection of earth electrodes and interconnection of metallic parts to minimise potential differences 10 29.04.2011 Technical Session - Home Networks - Geneva

11. ITU-T Study Group 5 Protection parts (cont) SPDs and cable screens are earthed IEC 60364-4-44 has the possibility of bonding the PE to the structure earth on each floor to reduce loop sizes 11 29.04.2011 Technical Session - Home Networks - Geneva

12. ITU-T Study Group 5 Philosophy of Protection o The first method of protection is to install a Multiservice Surge Protective Device (MSPD): These are described in Recommendation K.66 (currently called a Combination Protection Unit (CPU). They provide equipotential bonding of the ports at the equipment. 12 29.04.2011 Technical Session - Home Networks - Geneva

13. ITU-T Study Group 5 Philosophy of Protection They will protect against surges induced into the services and internal wiring, and against conducted surges let through by the primary SPD. 13 29.04.2011 Technical Session - Home Networks - Geneva

14. ITU-T Study Group 5 Philosophy of Protection (cont) o Power and telecommunication Network operators may install SPDs in lightning prone areas. o If not, it is recommended that SPDs be installed as required. o These primary SPDs (telecoms and mains) protect MSPDs, secondary protection and the house wiring. 14 29.04.2011 Technical Session - Home Networks - Geneva

15. ITU-T Study Group 5 Classification of ports o Equipment can have a combination of internal and external ports: External ports are protectable by a GDT on the telecommunications ports and a mains SPD on the mains port. They must comply with a coordination test. 15 29.04.2011 Technical Session - Home Networks - Geneva

16. ITU-T Study Group 5 Classification of ports Internal ports require a unique SPD designed according to IEC 61643. There is no coordination test in K.21. Guidance on classification of ports is given in K.44 and K.75. Incorrect classification may result in damage. 16 29.04.2011 Technical Session - Home Networks - Geneva

17. ITU-T Study Group 5 Mechanisms of damage o Strike to the structure (S1) may result in damage to external ports (conducted surges) and internal ports (induced surges) o Strike near to the structure (S2) may result in damage to internal ports (induced surges) 17 29.04.2011 Technical Session - Home Networks - Geneva

18. ITU-T Study Group 5 Mechanisms of damage (cont) o Strike to the services (S3) may result in damage to external ports (conducted surges) and internal ports (conducted surges). This is the work introduced by NTT. This issue will be studied over the next few months. o Strike near to the services (S4) may result in damage to external ports (induced surges). 18 29.04.2011 Technical Session - Home Networks - Geneva

19. ITU-T Study Group 5 Practices which may cause damage o Internal port connected to external cable. o The interconnected pieces of equipment are connected to different un-bonded electrodes. 19 29.04.2011 Technical Session - Home Networks - Geneva

20. ITU-T Study Group 5 Risk o Risk is covered in some ITU-T documents but not for damage of customer equipment. o Risk is also covered in IEC 62305-2, but not for damage of customer equipment. o Need to consider loss versus frequency of damage. 20 29.04.2011 Technical Session - Home Networks - Geneva

21. ITU-T Study Group 5 Risk (cont) o Recommendation K.hnwr will contain the information for performing a risk assessment and also an example risk assessment. o The frequency of damage will be determined. 21 29.04.2011 Technical Session - Home Networks - Geneva

22. ITU-T Study Group 5 Relevant Standards o The following ITU-T documents are relevant. K.21, K.44, K.66, K.71, K.74, K.75 and K.hnwr o The following IEC documents are relevant IEC 60364-4-44, IEC 61000-4-5, IEC 61643 parts 12, 21 and 22 and IEC 62305 series 22 29.04.2011 Technical Session - Home Networks - Geneva

23. ITU-T Study Group 5 Conclusion o If we are to prevent damage to HN equipment we need: Adequate resistibility of equipment. Correct classification and use of ports. Good installation practices. Correct earthing and bonding. Protection for external and internal ports as necessary. _________________________________________________ 23 29.04.2011 Technical Session - Home Networks - Geneva