6.5.3
Functional grounding
A module with exposed conductive parts is considered to be in compliance with UL 1703 only when it is
electrically grounded in accordance with the instructions presented below and the requirements of the
National Electrical Code.
Common hardware items such as nuts, bolts, star washers, spilt-ring lock washers, flat washers and the
like have not been evaluated for electrical conductivity or for use as grounding device and should be
used only for maintaining mechanical connections and holding electrical grounding devices in the
proper position for electrical conductivity. Such devices, where supplied with the module and evaluated
through the requirements in UL 1703, may be used for grounding connections in accordance with the
instructions provided with the module.
Install functional grounding for the solar power system when you are installing it in a country or a
system in which functional grounding is necessary or prescribed.
Direct grounding with a direct connection between the pole and the ground is not permitted. We
recommend functional grounding for large PV systems.
When installing the functional grounding, ensure that only the negative terminal of the module field
is grounded.
Only use inverters or other components for which the manufacturer enables functional grounding
or provides a ground kit that fulfils the above requirements.
TRANSFORMERLESS INVERTERS
Insofar as this is permitted by regulations depending on the site of installation, transformerless
inverters can also be used if the potential of the DC side to the ground or ‘0’ is less than 600 volts (<600
V DC).
When using transformerless inverters, the instructions of the inverter manufacturer shall be observed.
WARNING!
Fire hazard for improper grounding!
