Permitted voltage supply systems

TN and TT systems – voltage systems with directly grounded star point

Use is possible without restrictions.

IT systems – voltage systems with non-grounded star point

Use is only permitted with adherence to the following measures:

• The device must be connected to the protective earth. Observe the Notes on PE connection.
• If an insulation monitoring device is used, it must be capable of measuring the insulation resistance of the grid even if ground capacitances are present in the system.
• In the event of a line-side ground fault, the DC link voltage may increase. This can be prevented by using an external braking resistor; in this case, the smallest permissible braking resistor is sufficient.
• The EMC limit values for interference emission are not specified for voltage supply systems without grounded star point (IT systems). The effectiveness of line filters is severely limited.

It is possible to deactivate the EMC capacitors used in the device, which reduces the capacitance to ground. This affects the interference suppression of the device and may impair electromagnetic compatibility (EMC).

To deactivate the EMC capacitors, proceed as follows:

Size 0S, 0L:

1. Only deactivate the EMC capacitors when used in IT systems, see chapter Use in IT systems for sizes 0S and 0L.
2. Mark this on the nameplate in the "IT system activated" box provided for this purpose.

Sizes 3 – 8:

3. Remove all existing EMC contact screws from all devices only when used in IT systems. For the positions of the EMC contact screws refer to the product manual > chapter "Device structure" > Size 3.
4. Mark this on the nameplate in the "IT system activated" box provided for this purpose.

Voltage systems
with grounded outer conductor

Use only for nominal line voltages up to max. 240 V.