DC Cables(or SOLAR CABLE)

DC cable are used for passing DC current from source to destination.
In case of DC cable sometimes we can also use Single Strand cable, But we never prefer the use of Single Strand cable in case of AC because of Skin effect.

Skin effect

When AC current flows through a conductor then an magnetic flux induces in it and this magnetic flux is greater at the center due to which concentration of electron is increase at the outer surface of the conductor and decrease at inner surface of the conductor. As a result current flow mainly on outer surface of the conductor. Due to this effective area for current flows in our conductor decrease and this is know as skin effect.
1-Due to skin effect resistance of the conductor is increase and conductivity decrease.
2-To reduce skin effect we mostly use Multi-stranded conductor for AC current flow.
Note:-Skin effect depend on frequency if frequency increase skin effect increase and, In case of DC there is no skin effect that is a reason due to which sometime we use Single Strand conductor in case of DC and Multi-stranded conductor in case of AC. But due to flexibility issue we use and as surface area of Stranded wire is higher than original cylindrical wire. As a result extra surface area helps in flow of more currents than original cylindrical wire. Therefore Multi-stranded conductor in case of DC also. Note:-More the number of strands in the cable, the more flexible but the cost of the cable will increase

How to calculate size of cable by the number of strand in the cable?

As we know that ,Area=π*(Radius)^2
Lets we have diameter(d) of one strand=0.2mm
then,
Area=(π*d^2)/4
if diameter=0.2mm
Area of one strand=(π*d^2)/4
=(3.14*0.04)/4
=0.0314mm2
if we have number of strand=16
then, Area of cable=16*0.0314
=0.5024mm2 it is approximately 0.5mm

Similarly, 1mm wire have 32 strand of 0.2mm
As, Area of cable=32*0.0314
=1.0048mm2

SOLAR CABLE

Solar cable is a type of DC cable with double insulation mostly. This double insulation provide extra protection from temperature and UV light. solar cable can be categorize according to the temperature,operating voltage,material used and type of certification issue to the cable.
For example in India polycab company have different types of solar DC cable.

Solar dc cable specification (or solar cable types)

SOLAR DC CABLE TYPE-3

1)) Annealed Flexible Cu Conductor
2)) Non TUV Certified 

3)) DC Voltage = 1.5 Kv
4)) Standard: UV resistant according to DIN 83387
5)) It is insulated with XLPE and sheathed with UV stabilized PVC ST2 compound(It is odorless non-toxic,plasticized PVC grade with calcium carbonate).

SOLAR DC CABLE TYPE-1

1)) Tinned Flexible Cu Conductor
2)) TUV Certified
3)) DC Voltage = 1.8 Kv
4)) Standard: TUV Specification-2 Pfg 1169/08.2007, Flame retardant according to IEC 60332-1-2,Halogen free according to EN 50627-2-2,Ozone resistant according EN 50396,Weather/UV resistant according to DIN 53387
5)) It is insulated and sheathed with cross linkable LSOH(low smoke zero halogen) which has UV as well as Ozone protection property.

Solar Cable Certified according to EN 50618(E Beam)

1. Insulation:-Cross linkable (E Beam) LSZH Insulation
2. Sheathed:-Cross linkable (E Beam) LSZH Sheathed Solar Cable as per EN 50618
3. Flame retardant,low smoke as we use Cross linkable LSZH material
4. Flexible Tinned Copper Conductor of class 5.
5. As in this E Beam is used therefore it is more flexible and we can bend it more.
6. Max Conductor Temperature -40°C to 120°C.
7. UV,ozone,temperature and hydrolysis resistance.