Solar extension cable

With this solar extension cable set (20 metres, 4mm²) you can bridge enormous distances between your solar modules and the technology. This length is ideal when you need to place your panels in a sunny spot in the garden, on a distant garage or an outbuilding, while the inverter or storage system is installed centrally in the house.

The set consists of two double-insulated PV cables (1x red for plus, 1x black for minus). Both ends are already professionally fitted with MC4-compatible plugs and sockets ("Plug & Play"). The conductor made of tinned copper ensures durability; with this long length, the physical voltage drop should be taken into account (see notes). The cables are designed for permanent outdoor use in all weather conditions.

Highlights at a glance

• Enormous range: 20 metres in length gives you maximum freedom in choosing the location of your modules, far from the house connection.
• Plug & Play: Ready for immediate use thanks to pre-assembled MC4-compatible connectors (no crimping needed).
• Safety set: The colour combination red (+) and black (-) prevents polarity errors over long distances, where you might often lose track.
• Weatherproof (IP67): The plug connections are dustproof and waterproof; the insulation withstands extreme temperatures (-40°C to +90°C).
• UV- & ozone-resistant: The robust sheath made of cross-linked polyolefin does not become brittle even after years in the sun.
• Certified quality: Suitable for system voltages up to 1000V/1500V DC (TÜV/EN standards).

Areas of application

The 20-metre extension is designed for extensive installations:

• Ground-mounted systems: Placement of the modules at the end of the property for optimum solar yield.
• Outbuildings: Connection from garden shed, carport or barn to the main house.
• Façade installation: Routing the cables from high roofs or façades down to the basement technical room.
• Shading management: Avoiding large sources of shade (trees, neighbouring buildings) by installing panels further away.

Installation & safety instructions

• Note voltage drop: With 20 metres length (40m current path there and back), resistance occurs. For grid-connected high-voltage systems (strings with several modules, >100V) 4mm² is unproblematic. For individual 12V/24V modules or standalone/off-grid systems, the loss at 4mm² is noticeable (approx. 3-5%). A 6mm² cable would be more efficient here.
• Do not create coils: Never wind excess cable into tight coils under high current (induction heating). Instead, lay it in large loops.
• Mechanical protection: Never lay the cable of this length unprotected on the ground (lawnmowers, animals!). Use cable ducts or protective tubes.
• Strain relief: Secure the cable immediately after connecting it to the module so that the weight of 20m of cable does not pull on the junction box.

Properties

FAQs about the 20m solar extension cable

Is 4mm² still sufficient for 20 metres in length?

Depends on the application. For a typical "balcony power station" (approx. 30-40V module voltage), the loss at full load is around 3-4%. This is technically safe, but means a slight reduction in output. For high-voltage strings (e.g. 300V), the percentage loss is negligible. For 12V systems (campers/battery charging), the voltage drop is too high; here we recommend 6mm² or 10mm².

Can I bury the cable?

Only in protective conduit. The insulation is weather-resistant but not certified for direct burial (risks: stones, moisture, rodents). A simple PE empty conduit from a DIY store provides sufficient protection.

Are the connectors compatible with every inverter?

Yes. The MC4 standard is universal. The cables suit all common modules and inverters (Hoymiles, Deye, Growatt etc.).