Grounding The Battery And The Pv Plant - SMA Sunny Island SIC50-MPT Installation Manual

SMA Solar Technology AG
6.3.2 Grounding the Battery and the PV Plant
DANGER!
Danger to life due to high voltages at the battery's negative ground terminal.
• Ground the battery.
Not grounding the battery is permitted only if the battery connections have protection
against accidental contact.
NOTICE!
Grounding the positive pole may lead to destruction of the battery.
• Never ground the positive pole of the battery or the PV plant.
Cross-section of the Protective Conductor
SMA Solar Technology AG cannot make any general statements regarding the required cross-section
of the protective conductor for external grounding of the battery. The conductor dimensions depend
on the type and size of the battery connected, the external fuse (DC side) and the material used in
the protective conductor.
Determining the cross-section
When determining the cross-section of the protective conductor, all standards and
guidelines that apply at the installation location must be observed.
The required cross-section of the protective conductor can be calculated using the following formula.
Tripping times for short-circuit currents of between 2 000 A and 10 000 A are typically about 25 ms.
A protective conductor with a cross-section of 16 mm² is therefore sufficient for short-circuit currents
up to 10 000 A.
Installation Guide
t = short-circuit duration in seconds
I = maximum battery current (short-circuit current) in amperes
SC
S = conductor cross-section in mm²
Electrical Connection
SIC50-IA-en-11 21