Photovoltaic Wires & Cables

The main difference between AC electrical and low voltage DC photovoltaic system installation is different voltage range at PV systems and much higher currents. The system's careful design should consider proper wire sizing allowing for efficient operation. The most important parameter is the wire section. Inappropriate wire sizing could result in excessive heating and even fire due to large current. Properly connected and sized wiring won't require any maintenance for years. Exterior modules and other PV components connection wires and cables should be used with UV radiation resistible insulation. Standard wire and cable insulation cracks under years of exposure to atmospheric conditions and UV radiation. The temperature range is also important. Exterior cables should allow for temperature range from -45°C to up to +80°C or even more. Application of such cables will enable efficient system operation for the next two decades or longer. Standard, usually stranded wires and cables are used for interior connections. A simple rule to follow in small systems is 1 mm2 wire area/1 A current. Its application will prevent wire overheating and curb loss within required limits.

Wires & Cables

Some general recommendations that should be followed are:

The maximum allowed loss between battery and charge regulator is up to 1 %.
Maximum allowed loses between solar modules and charge regulator are up to 3 %.
Maximum allowed loses between charge regulator and loads are up to 7 %.

Anyhow, the loss should be kept at minimum if possible. The tables below are a fine tool to guide you through your photovoltaic system design. The maximum power at specific wire length and required wire section at 1 and 3 % power loss is presented in the tables.

distance wire cross-section (mm2)
4 6 10 16 25 35 50
1 m 160 240 400 660 1000 1400 2010
2 m 80 120 200 320 500 700 1000
4 m 40 60 100 160 250 350 500
6 m 25 40 65 100 160 230 330
8 m 20 30 50 80 120 170 250
10 m 15 20 40 60 100 140 200
15 m 10 15 25 40 65 90 130
20 m 8 10 20 30 50 70 100
30 m 5 8 10 20 30 45 65

TABLE 1: Maximal load power in watts for 12 V DC voltage and 1 % loss

distance wire cross-section (mm2)
1.5 2.5 4 6 10 16 25
1 m 180 300 480 720 1200 1930 3020
2 m 90 150 240 360 600 960 1500
4 m 40 70 120 180 300 480 750
6 m 30 50 80 120 200 320 500
8 m 20 35 60 90 150 240 370
10 m 15 30 45 70 120 190 300
15 m 10 20 30 45 80 120 200
20 m 8 15 20 35 60 90 150
30 m 5 10 15 20 40 65 100

TABLE 2: Maximal load power in watts for 12 V DC voltage and 3 % loss

distance wire cross-section (mm2)
4 6 10 16 25 35 50
1 m 640 960 1600 2570 4020 5630 8040
2 m 320 480 800 1280 2010 2810 4020
4 m 160 240 400 640 1000 1400 2010
6 m 100 160 260 420 670 930 1340
8 m 80 120 200 320 500 700 100
10 m 60 90 160 250 400 560 800
15 m 40 60 100 170 260 370 530
20 m 30 45 80 120 200 280 400
30 m 20 30 50 80 130 180 260

TABLE 3: Maximal load power in watts for 24 V DC voltage and 1 % loss

distance wire cross-section (mm2)
1.5 2.5 4 6 10 16 25
1 m 720 1200 1930 2900 4380 7740 12090
2 m 360 600 960 1450 2410 3870 6040
4 m 180 300 480 720 1200 1930 3020
6 m 120 200 320 480 800 1290 2010
8 m 90 150 240 360 600 960 1510
10 m 70 120 190 290 480 770 1200
15 m 40 80 120 190 320 510 800
20 m 35 60 90 140 240 380 600
30 m 20 40 60 90 160 250 400

TABLE 4: Maximal load power in watts for 24 V DC voltage and 3 % loss

Other

Other parts of PV system electrical installations, similar to AC electrical installations, include plugs and jacks, fuses, switches, PVC installation tubes or wall ducts etc. Special consideration should be paid to selection of fuses, for only DC rated fuses are suitable. There are a great variety of fuses available in the market, such as classical blow-up fuses, automatic fuses similar to the ones used in AC circuits. Plugs and jacks used in PV systems must be different from the AC wiring plugs and jacks. The plugs and jacks used in DC wiring must differ from the ones used in AC wiring. Application of the same plugs and jacks type is not allowed due to security reasons.

Solar Cables - Links

DRAKA Kabel - DRAKA is the largest manufacturer of low-voltage cable and wire in the Netherlands. Established in 1910, DRAKA has been producing and selling cable and wire for a wide range of applications and in close cooperation with end-users.

HIS Solarsysteme - HIS is one of the leading providers of switches and cables for photovoltaic systems.

HELUKABEL - HELUKABEL® is a leading international manufacturer and supplier of wires & cables, custom cables, cable accessories, data-network-bus-engineering and pre-assembled cable protection systems for robotics and handling systems.

SOLAR-KABEL - Full-Range Product Line for Photovoltaic Cabling. Special Solutions for Your Specific Needs.

LAPP KABEL - Cables, plugs and photovoltaic accessories.

USA Wire & Cable - USA Wire & Cable is a global supplier of electrical wire and cable, including armored cable, high temperature cable, telephone and power cable.


Solar Connectors - Links

Wieland Electric - Pluggable solutions for solar technology made by Wieland Electric. With the gesis AC-SOLAR round connector series, installation on the AC side now also profits from the advantages of a pluggable connection: time savings during assembly, clear structure and easy maintenance.

Multi Contact - With over 15 years of experience in this field, Multi-Contact is leading provider of dependable connector systems for photovoltaic installations.

TE Connectivity - TE is a leading manufacturer of electronic components and solutions for solar energy.

Lumberg - Lumberg offers a comprehensive product range for photovoltaic connectivity.


Junction boxes

Spelsberg - for almost 100 years Günther Spelsberg company has been representing competence in the development, quality production and service reliability in the electrical and enclosure industry.

FPE Fischer - aluminium junction boxes for photovoltaic systems.

SKS Kontakt - photovoltaic junction boxes.