4 Product Overview
SMA Solar Technology AG
Operating manual
11
NA-BOX-12-3-20-BE-en-12
4
Product Overview
4.1
Product Description
The NA-Box is an automatic transfer switch. It enables the operation of an SMA multicluster system on a utility grid in
accordance with the VDE-AR-N 4105 application regulations. In the event of a grid failure, the NA-Box disconnects
the SMA multicluster system from the utility grid via a redundant tie switch.
A
C
D
F
G
E
G
B
Figure 2: NA-Box with cabinet door open
Position
Designation
A
Protective cover
Prevents inadvertent contact with live components during operation and thus protects
from electric shocks. When the product is in operation, the protective covers must al-
ways be mounted.
B
Type label
The type label clearly identifies the product. The type label must remain permanently at-
tached to the product. You will find the following information on the type label:
• Device type (Model)
• Serial number (Serial No. or S/N)
• Date of manufacture
• Device-specific characteristics
C
Fuse holder 6 A
Used as receptacles for cylindrical thermal fuses (6 A, tripping characteristic gG). The
thermal fuses protect the connected conductors from excessive heat build-up due to
overload or short circuits.
D
External grid and PV system protection device which interrupts the connection between
the power generation system and the electricity grid in the event of voltage- or fre-
quency disturbances via the control of a redundant tie switch.
The grid and PV system protection device monitors the utility grid voltage and fre-
quency for disturbances. If the values fall below the lower limits or exceed the upper
limits, the grid and PV system protection device disconnects the power generation sys-
tem from the utility grid by opening the redundant tie switch.
The NA-Box is fitted with the grid and PV system protection device manufactured by
Bender GmbH & Co.KG.
