SOLAR PUMPING Guidelines - Electrical design and installation of solar pumps
PUMP POWER CABLE EXTENSION If the pump is correctly sized, made of stainless steel and equipped with a quality motor, then the weak point of the system
will not be the pump but its installation. Indeed, the pump is delivered with a small cable (50cm to 1m maximum) that must
be connected to the power cable that goes down into the borehole.
This connection must be perfectly sealed and durable in time. For this, the 3 approved systems are shown in Table 5 below.
TABLE 5: METHODS OF CABLE EXTENSION, QUALITATIVELY SORTED
DESCRIPTION PICTURE OF A KIT KIT INSTALLED BEST QUALITY Plastic junction box with liquid resin This is a kit consisting of an envelope (housing) generally
spindle-shaped, tightened at the ends to tighten the
cables, and flared in the middle to leave the volume
necessary for connectors in the central part.
Once the connection is made and the box closed
around the connection, the resin supplied with the kit is
poured, then hardens and makes the assembly long-term
waterproof.
SECOND QUALITY Heat Shrink Solder Sleeves It is a set of sleeves composed of 3 parts:
•
Crimp sleeve to connect the conductors to each other
•
Heat-shrinkable sleeves to put on wires
•
Heat-shrinkable sheath to put on the entire cable
Warning: the installation of this kit requires some
specific skills to be really waterproof.
APPROVED BUT TO AVOID IF POSSIBLE Cable extender It is a waterproof kit to screw. It is not recommended
because:
•
Once the connection is made, there is still air in the
connection part. This system is not resistant to
pressurization and is generally not waterproof above
5bar (50m deep).
•
It does not fit on flat cables, but most pumps are
equipped with flat cables.
All systems done with tape (electric or standard), connector blocks, WAGO, … with or without “waterproof box” ARE
PROHIBITED. These systems (main ones of which are presented in figure 11) are not resistant to pressure, do not last long,
and / or do not provide a real sealing. These boxes are called «waterproof» because they are rainproof, but they are not
submersible at all.
FIGURE 11: MAIN PROHIBITED SYSTEMS FOR SUBMERSIBLE EXTENSIONS
