S 1.5 Galvanic separation of external lines

Initiation responsibility: Head of Site/Bldg Technical Service

Implementation responsibility: Site/Bldg Technical Service

Many in-house networks have a direct galvanic connection to external lines. This may be the case with telephone lines, power supply, data networks with remote data transmission connections, but also with gas and water supplies.

Through these mains connections, external voltage and overvoltage can be imported into the building. There are a number of electric, electronic or software-based measures which can protect networks against external factors. However, absolutely reliable protection cannot be guaranteed in all cases. Systematic galvanic separation of outside lines at the entry points into the building is then the last resort. This can be done, for instance, by installing a switch which will connect the line only when required (remote maintenance).

For the protection of inseparable lines (telephone, data, power, gas, water) against overvoltage, consideration should be given to installing an overvoltage protection device (c.f. S 1.25 Overvoltage protection).