Electricity + Control October 2016

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unless the cable or its protective sheathing are adequately shielded
or of a special design to withstand the effects of such exposure.
Protection of cables from physical damage
TUV approved PV cables are manufactured with mechanical robust-
ness. These solar cable are insulated twice with an insulation around
the conductor and an insulation outer jacket. If the outer jacket is dam-
aged or cut, there is another layer providing the necessary protection
for the conductor. The insulation for PV cables is also manufactured
by using the electronic beam cross linking procedure which improves
the shear and impact strength of the cable thus protecting the cable
more effectively.
Notwithstanding the above, damage can still occur during PV
cable installation if sharp edges and corners exist. Moreover, PV
cables are installed through openings drilled in the structural metal
work of the PV system creating sharp holes that can cut through the
insulation of the cable.
PV cables and their insulation shall be protected by ensuring that
every hole is bushed so as to prevent abrasion of the cable insulation
or even compressed under the weight of modules. PV cables must
be protected from possible movement by the fastening of cable ties,
clips and other attachment tools ensuring that the electrical properties
of the cables is not in any way compromised.
Protection of PV cables against corrosion
The insulation for PV cables is manufactured by using the electronic
beam cross linking procedure. These cross linked insulation materials
greatly improve the chemical resistance of the cable thus protecting
the cable more effectively. The type of PV cable insulation must be
selected to be able to protect the cable from corrosive chemicals.
The protection of PV cable can be provided by fixing the cable in
positions where the cable or its protective insulation is adequately
shielded or exposed to corrosive chemicals or as mentioned, of special
design to withstand the effects of such exposure.
PV cables that are likely to be exposed to chemicals should have
an insulation cover that has a high degree of resistance to chemicals.
The PV cables can be afforded protection by being kept or shall
not be fixed within six inches from such corrosive materials the con-
tents of which might damage the cable or its insulation unless the
cable is adequately shielded or of a special design to withstand the
effects of such chemicals.
Protection of cables from animals
Pests like rodents feed on PV cables resulting in a loss of production
and extensive repair works if the issue is not addressed. Some of the
existing technology on the market to mitigate this situation involves
the use of barriers attached to structural members and rails. The two
take note
technologies in the market are:
♦ Heyco’s SunScreener
♦ Spiffy’s Solar screening
Conclusion
It can be noted that compliance with the relevant standards will
certainly achieve the code compliant and safe cable management
for PV cables. As a result of adhering to the design and installation
requirements, the entire PV cabling network can be adequately pro-
tected. The PV cable system will ensure reliability guaranteeing the
much required rate of return on the capital investment for clients.
maintenance of the installed system must follow to ensure that the
investment does not deteriorate and this can be achieved by peri-
odic inspections and verification of the soundness of all PV cables
and equipment. The maintenance can be achieved by drawing up a
maintenance management plan which can be agreed with the clients.
With the evolving of new technologies, installers must advise clients
on these new innovations and be able to advise on ways to improving
the old existing plants.
Factors for consideration in selecting the right technology for
protection of the PV cables should be based on code compliance,
ease of installation and cost.
References
[1] ISO 4892-1. 2016. Plastics -- Methods of exposure to laboratory
light sources. Part 1: General guidance.
[2] EN 50395:2005. 2011. Electrical test methods for low voltage
energy cables.
[3] EN 50396:2005: 2011. Non electrical test methods for low voltage
energy cables.
[4] IEC 60811:2012. Electric and optical fibre cables - Test methods
for non-metallic materials.
Morgan Havire is a Chartered Electrical Engineer with experi-
ence that includes site surveys, design, supervision, testing
and commissioning of new buildings and refurbishment of
existing ones. He has undertaken major projects as a principal
and lead design engineer responsible for all electrical and
electronic services on projects in South Africa, Zimbabwe,
Angola, Mozambique, Zambia and Equatorial Guinea. Morgan has undertaken
design assignments within teams working on projects in South Africa, Zambia,
Mozambique, Nigeria, Australia, United States, Nigeria and Equatorial Guinea.
Morgan has experience in sustainable building design concepts that include
photo voltaic solar power on projects. Enquiries: Email
• The lifespan of PV cables is generally 25 years.
• Continuous direct sunlight exposure causes cables to
degrade.
• Protection of cables from direct sunlight can be achieved by
implementing a code compliant wire management system.
CABLES + ACCESSORIES
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