ProMinent Sigma 3 Basic Operating Instructions Manual page 45

Earthing lines
Potential equalisation line (prescribed in
the area at risk from explosion)
Other units
Connect the electrical components of the entire installation supplied
cleanly and permanently to an electrically clean earthing point, e.g. with an
earthing bar on site - see earthing diagrams in the appendix.
The entire installation supplied is provided ex works with the necessary
potential equalisation lines. Electrically connect an additional potential
equalisation cable from the potential equalisation cables from this system
cleanly and permanently to an electrically clean potential equalisation
point, e.g. to a potential equalisation bar on site.
Install the other units in line with their documentation.
Installation, electrical
45