Sunny Island
Installation & Operating Instructions
BWRI33-12:EE
- 26 -
SMA Regelsysteme GmbH
The required cable cross-section of the grounding conductor can be es-
timated with the following formula for fused interrupters with disconnect-
ing times up to 5 s if a copper cable is used:
S =
(I
SC
2
∗
t)
143
t = disconnecting time in seconds, I
SC
= maximum battery current (short-circuit current) in
amperes, S = conductor cross-section in mm²
The maximum battery current can be seen in the data sheets for the bat-
tery. If this is not possible it can usually be estimated with the following
formula:
I
SC
=
C
0,05h
C = battery capacity in Ah
For an exact determination of the grounding conductor cross-section please refer to
the relevant standards (e. g. VDE 0100 part 540).
3.4.2 Connection of the battery
On the DC side a suitable storage battery has to be connected according to DIN
VDE 0510 (VDE specification for electric storage batteries and battery plants).
Make sure the cable to the storage battery has a sufficient cross-
section. Pay attention to the correct polarity of the connection to the
storage battery.
If the battery is to be grounded please follow the special instructions
in chapter 3.4.1.
