Copyright Bosch Solar Energy Corp., version 1.0
Page 14 of 19
Series and Parallel Wiring
The modules may be wired in series to produce the desired voltage output in the range of
maximum system voltage and input voltage of the required inverter. Connect the modules in
series electrically by connecting the positive (+) connector of one module to the negative (-)
connector of another. Only use modules of the same type for series connections. An arrangement
of several solar modules which are connected in series is often referred to as a “module string”.
To determine the maximum number of modules that may be connected in series, divide the
maximum system voltage as stated on the module label (or the maximum allowed by local
standards or codes, whichever is less) by the module open circuit voltage (Voc) printed on the
label, after correcting for temperature as required by local codes or standards.
The number of module strings connected in parallel without protective fuses should be limited to
two. If more than two strings are to be connected in parallel, then a series fuse is required for each
string in each non-earthed pole. Only DC fuses rated at the maximum system voltage should be
used. Maximum fuse rating should not exceed the maximum system voltage rating stated on the
module label.
DC Fuse Ratings
To calculate the minimum fuse size, multiply the short circuit current (Isc) rating of the module
by a factor of 1.56. The Isc value must take into consideration the maximum irradiation and
temperature of the installation site. If the loss of a fuse connection occurs, verify that the
maximum current rating was considered when calculating the fuse rating.
CAUTION
DO NOT connect or disconnect a Bosch Solar Energy module unless the array string is open-
circuited or all of the modules in the a r r a y string are covered. Take appropriate steps to black out
the top (cell side) of the solar modules as much as possible. The connectors are not designed to
make or break the full system current. Do not direct concentrated artificial lighting sources on the
modules or panels.
B.
Grounding
In order to ensure a code compliant installation, requirements for earth grounding and lightning
protection must be followed. In the United States, the grounding methods must comply with
Articles 250 and 690 of the National Electric Code (NEC).
According to the NEC, the installer must ground the m o d u l e frame. Use only UL Listed
grounding lugs suitable for outdoor. Alternate means of module grounding not covered within this
Manual may be acceptable. Contact Bosch Solar Energy for additional information regarding the
use of additional grounding techniques.
Please refer to Figure 7B for a typical earth grounding method for the module utilizing ground
lugs.
