International Telecommunication Union ITU-T Study Group 5 The

International Telecommunication Union ITU-T Study Group 5 The need for special requirements Tetsuya Tominaga Technical Session on Home Networks Geneva, 29/04/2011

AC mains plugs in global ITU-T Study Group 05 o There are many plugs in the world o There is no earth terminal in Japanese type JAPANESE TYPE Technical Session - Home Networks - Geneva

Japanese customer premises AC power o o ITU-T o Study Group 05 o o Voltage: 100 V rms Frequency: • 50 Hz Eastern Japan • 60 Hz Western Japan Configuration: TT Each PE has each grounding rod Technical Session - Home Networks - Geneva

Smart House is “Connected House” ITU-T Many kinds of equipment will be connected each other under the TT system. Study Group 05 Optic Fiber Smart Meter SPD：Surge Protective Device 7/3/2011 TTC Work. Shop 4

Bad installation and insufficient resistibility ITU-T Good installation and Adequate resistibility are needed. Study Group 05 Optic Fiber Smart Meter SPD：Surge Protective Device 7/3/2011 TTC Work. Shop 5

Philosophy of protection Good installation and Adequate resistibility of equipment ITU-T Classification of interface (K. 75) Adequate Resistibility (K. 21, K. 44, K. 66, K. 71, K. hnwr) Study Group 05 Optic Fiber SPD SPD Additional Protection (K. 66) Good Bonding (K. 66) Who knows K. 66? Is Japanese type grounding configuration special? 7/3/2011 TTC Work. Shop 6 SPD：Surge Protective Device

Selection for Required resistibility (K. hnwr/Draft) Figure 1/K. hnwr - Flowchart for determining required level of resistibility Identify the equipment and the number and type of ports ITU-T Determine the power induction limits Study Group 05 When the bonding configuration is not along with K. 66 Are there unique problems requiring high isolation values? Bad bonding configuration (K. 66 For example, the bonding wire length >1. 5 m ) Yes No Does the equipment have more than one port type? Yes No Are the power induction limits > 600 V? Yes No “Basic” “Enhanced ” 5. 2 Resistibility Recommendation K. 21 has two levels of resistibility “basic” and “enhanced”. Specification EN 50468: 2009 gives advice on the selection of “basic” and “enhanced”. EN 50468: 2009 advises: For equipment having only external telecommunication ports the resistibility requirements are defined in ITU-T K. 21 “Basic level”. For equipment having additional connections to networks e. g. power networks, the test levels are defined in ITU-T K. 21 “Enhanced level” The required level of resistibility can be determined in Figure 1/K. hnw. Information on “Special requirements” is contained in K. 44. “Special” Figure 1/K. hnwr - Flowchart for determining required level of resistibility 7/3/2011 TTC Work. Shop 7

Proposal: Special Resistibility (K. 44, K. 66, K. hnwr) ITU-T Study Group 05 TEST The special level is already described in K. 44 and K. 66. The external port is optical fibre now. So, All telecom. Ports are “Internal” The proposal is adequate Internal port test levels Telecom Mains municati Internal municati Internal power – on line – tel. Port – Internal on line – tel. Port Ether longitudi transvers Internal USB Port Mains longitudi transvers Internal (L 1 -L 2) Port nal e port power tel. Port nal e port line 4 k. V 13 k. V Combin Lightnin 10 k. V 10/700 10 k. V ation 13 k. V 4 k. V 13 k. V g Surge combina 10 k. V combina Current 10/700 limit Test tion combina tion resistor = tion 50 W Table II. 6 -1/K. 44 – Resistibility and safety requirements of customer premises equipment powered by mains power Proposal Technical Session - Home Networks - Geneva 10 k. V ? ? 6 k. V ? ? Under Study Coax. Port 6. 42 k. A 10/350 K. 75 For SPD

Concideration ITU-T Coordination of “protecters” and “Safety and Lightning protection” are important. Safety = Breaking Fuse Minimize of Damage ratio = No Breaking Fuse The impedance is need for coordination FUSE between SPDs Study Group 05 SPD 2 V 2 SPD 1 V 1 o Resistibility of inherent IC’s or circuit is becoming smaller, so it becomes more difficult to prevent the damage. V 0 o No Earth is Un safe? Coordination of protection Un safe method Class II without earthed SPDs Safe method Class II with earthed SPDs A A N N E E Safety and lightning Protection in no earth 7/3/2011 TTC Work. Shop 9

Bypass circuit and Safety standard ITU-T Study Group 05 o Conflict between Safety standards (e. g. IEC 60950) and Lightning protection (Recommendation K. 66 and so on). • Bypass circuits between AC mains and telecom ports described in K. 66 should be permitted in any case to protect telecommunication equipments against overvoltages. • The protector operate voltage would be higher than the insulation test voltage. Unfortunately the safety standards, e. g. IEC 60950, do not allow voltage limiters to bridge supplementary insulation, double insulation or reinforced insulation. TD 566 is describe in detail, please read them. Technical Session - Home Networks - Geneva

Conclusion ITU-T Study Group 05 7/3/2011 o If we are to prevent damage to HNW equipment we need: • Adequate resistibility of equipment • Special resistibility of equipment, when the equipment can not be controlled the installation environment. • Correct classification and use of ports • Good installation practices • Correct earthing and bonding • Protection for external and internal ports as necessary. Work. Shop TTC 11