6.6 Land based systems
off-grid system grounding Do not ground the positive or negative of the PV array: the PV negative input of the MPPT is not isolated from the negative output. Grounding the PV will therefore result in ground currents. The PV frames however may be grounded, either close to the PV array or (preferably) to the central ground. This will provide some protection against lightning. Ground close to the battery. The battery poles are supposed to be safe to touch. The battery ground should therefore be the most reliable and visible ground connection. Required cross-section: DC ground cabling should be able to carry a fault current at least equal to the DC fuse rating. The chassis of the inverter or Multi/Quattro must be grounded (basic insulation between AC and chassis). The chassis of the MPPT solar charger must be grounded (basic insulation between AC and chassis).
AC distribution with fuses or MCB’s: not shown. PV array and PV frame grounding: not shown.
off-grid with generator One ground only, close to the battery. Required cross-section: DC ground cabling should be able to carry a fault current at least equal to the DC fuse rating. Similarly, AC ground cabling should be able to carry a fault current at least equal to the AC fuse rating. A GFCI will be functional only if the chassis of the Multi/Quattro is grounded.
off-grid with high power generator Ground the genset directly at the central ground.
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