Installation manual

PS10270JENAA01 20/10/2004 41
Installing the hardware
High leakage currents
In the event of a power line fault near telephone lines, service technicians must be aware
of the possibility of high leakage currents on metal system surfaces.
Leakage currents normally flow safely through the power cord to protective ground.
Isolate the telephone network lines before any servicing on the ICS.
Lightning overvoltages
Transient overvoltages due to lightning can be conveyed by the supply cables and
telephone lines of the installation:
• the electrical power supply installation of the room must be protected against
lightning-generated overvoltages coming from the power supply network
• the telephone installation must be protected against lightning-generated overvoltages
by inserting protection modules between the PSTN and the distribution frame