Mitigation method/Results/Conclusion As can be seen from Figure 2.5-1, the equipment is not installed according to the manufacturer's instructions. The idea of the manufacturer was that the equipment, provided with high-current inherent protection, would be earthed via the backside of the front panel to the installation frame that is further connected to the bonding system of the telecom centre. In the damaged system, however, the installation frame was painted with non-conducting paint, and this prevented the intended contact from the backside of the panel. Moreover, the manufacturer of the installation frame had installed the bonding bar of the frame on insulating supports, and although the installation personnel had connected the bar to the bonding system, the frame was not earthed. This example contains several general principles of problem solving methodology for the operator: • When a problem arises, react immediately. • Try to find the real reason of the problem by analysing the condition in the field and by laboratory testing. • Cooperate effectively with the manufacturer. • Check whether earthing instructions have been followed properly. • Check that the instructions are understood and taken into account throughout the country. • Arrange courses for installation personnel on practical problems and protection practices. It also shows one particular problem of bonding: paint may sometimes cause discontinuities. References Recs ITU-T K.27, ITU-T K.35, ITU-T K.40, ITU-T K.56; Annex C. Case study 2.5 – 2 –