SOLAR PUMPING Guidelines - Electrical design and installation of solar pumps
5
GROUNDING SYSTEM All solar pump systems must be grounded via a ground rod. Equipment to connect to the
ground network are:
EQUIPMENT TO BE GROUNDED SIZE AND TYPE OF WIRE TO CONNECT TO THE GROUND ROD Solar panels, usually a small hole is already made in the frame of the panel
where the symbol earth (see above) is already present.
Same size as solar panels cables
Solar panel support / stand and metallic frames
16 mm² / Insulated or Bare Copper
Lightning arrestor inside the protection cabinet
16 mm² / Insulated
Metal frame of pump controller or inverter if in a metal frame
16 mm² / Insulated
Pump controller or solar pump inverter
Same size as power supply cables
Submersible pump
Same size as power supply cables
6
LOW LEVEL WATER SENSOR (IN THE BOREHOLE) All pumps must be protected against lack of water. The lack of water occurs when the pumping rate is greater than the
capacity of the well, for example in the dry season or in case the slots of the well screen are clogged.
In the large majority of cases a sensor provides protection against «lack of water», placed between 10 and 30 cm above
the pump. Most of the time this is a separate probe (figure 8), which is fixed with stainless steel collars (cerflex) or plastic
collars (colson) on the discharge pipe, or on the galvanized steel suspension cable of the pump when the discharge pipe is
flexible. The probe should never be attached to the power cable, as this cable must always remain relaxed.
Some suppliers (such as Grundfos - only in the SQFlex range) integrate this probe directly into the pump supply cable
(figure 9), but this is still rare. In any case, you must include this safety feature into your quotation request.
FIGURE 9: GRUNDFOS PUMP - SQFLEX WITH LOW
LEVEL SENSOR INTEGRATED ON THE CABLE
FIGURE 8: TYPICAL SENSOR AND ITS FIXING ON
THE PIPE
Grounding
symbol
