SMA Solar Technology AG
Electrical Connection of the Automatic Switch Box S
Technical Description
SBU2200-TEN083320
77
8.2.4 Consumer System (X4/Backup Loads)
Connect the X4/Backup Loads connection to the loads. Use a conductor cross-section of max. 6 mm².
The terminals are designed as spring-type terminals. The nominal AC current is 25 A.
Due to its design, the Sunny Backup can only deliver limited current in the event that body contact is
made with the device. This current cannot trigger a 16 A line circuit breaker commonly used in
building installations. Therefore, a RDC must be installed.
However, if all load circuits are protected with line circuit breakers with a maximum rating of B6, the
Sunny Backup can provide corresponding current. If the present form of the standard in the respective
country allows, the RCD is not required.
DANGER!
Risk of death from feedback into the public grid.
If three-phase loads are connected in the backup system, feedback into the public grid via
one of the L conductors may occur in the event of a grid failure.
• Only run single-phase loads in a Sunny Backup System S.
DANGER!
Risk of death from leakage currents.
Install a RCD switch between the Automatic Switch Box S and the loads.
NOTICE!
Device fault due to overcurrents.
The grid current and the current from the Sunny Backup 2200 can combine with each other
and exceed the permitted 25 A limit.
• Install a 25 A fuse between the Automatic Switch Box S (X4/Backup Loads
connection terminal) and the loads.