SMA AUTOMATIC SWITCH BOX M-20 - Manual (Page 30)

5 Electrical Connection SMA Solar Technology AG
30 AS-BOX-M_L-IA-IEN110320 Installation Guide
5.3 Connecting functional and operational grounding
TN system:
When connecting in a TN system, only connect a functional grounding. This connection activates the
EMC interference elimination measures in the Automatic Switch Box. The functional grounding is not
identical to the protective grounding of the Automatic Switch Box.
TT system:
When connecting in a TT system, connect an operational and a functional grounding. This connection
activates the EMC interference elimination measures in the Automatic Switch Box. By means of the
operational grounding, the neutral conductor of the Sunny Backup is grounded via a resistor. The
operational and the functional grounding are not identical to the protective grounding of the
Automatic Switch Box.
Requirements:
☐ In case of a functional grounding, the cable cross-section for copper cables is 6 mm².
☐ In case of a redundant connection of the operational grounding, the cable cross-section for
each copper cable is ≥ 6 mm².
☐ In case of an ordinary connection of the operational grounding, the cable cross-section for
copper cables is ≥ 10 mm².
Connection terminals "PE" in the Automatic Switch Box
The Automatic Switch Box corresponds to protection class II. The connection terminals "PE" in
the connection area do not serve as a protective grounding of the Automatic Switch Box
enclosure. Via the connection terminals "PE" in the connection area of the Automatic Switch
Box, PE of the individual terminals will only be routed through the Automatic Switch Box and
distributed in the following installation.