Can I use ordinary cable for solar panels?

No. The DC leads should use solar (PV) cable, which is UV-resistant and rated for outdoor DC. Ordinary indoor flex degrades outdoors and isn't suitable.

Can I extend a solar panel cable?

Yes, with a proper solar extension lead using matched MC4 connectors rather than cutting and joining cable. Keep the total run as short as practical to minimise small resistance losses.

Inverters & components

Solar cables and connectors: a plain guide

Cables are easy to overlook, but the right cable, properly routed, is part of a safe and efficient plug-in solar setup. The leads from a panel are usually 'solar cable', which is built for the job.This guide explains the cable types and the safe-routing basics. It pairs with our guide to MC4 connectors.

Written and edited by Christopher Panteli

Last reviewed 21 June 2026

Christopher is the founder and editor of MyPlugInSolar. He oversees the site’s research standards, data tools and editorial process. He is not an electrician or solar installer, and specialist technical claims are sourced from official documentation or reviewed by appropriately qualified professionals.

Why solar cable is special

The DC leads on a panel use cable designed to sit outdoors for years: UV-stable insulation, a wide temperature range and the right current rating. Standard mains flex isn't built for that exposure, which is why you shouldn't substitute it for the DC side.

Extension leads and joining cable

If a panel's lead doesn't reach the microinverter, use a proper solar extension lead with matched MC4 connectors rather than cutting and joining cable. Pre-made leads keep the connection weatherproof and correctly rated. Keep runs as short as practical — very long DC runs lose a small amount of energy to resistance.

Routing cables safely

Avoid trip hazards and pinch points (doors, windows, walkways).
Protect cable from abrasion, sharp edges and UV where you can.
Don't run DC cable through water-collecting spots or standing water.
Secure cable so it can't be tugged on the connectors.

Safety and compliance

The DC side connects to a microinverter that feeds your mains; any fixed-wiring connection must be done by a qualified, registered electrician. Plug-in solar is not yet legal to use in the UK — see the legal status.

Frequently asked questions

Can I use ordinary cable for solar panels?: No. The DC leads should use solar (PV) cable, which is UV-resistant and rated for outdoor DC. Ordinary indoor flex degrades outdoors and isn't suitable.
Can I extend a solar panel cable?: Yes, with a proper solar extension lead using matched MC4 connectors rather than cutting and joining cable. Keep the total run as short as practical to minimise small resistance losses.

Sources

1. BS 7671 Requirements for Electrical Installations (IET Wiring Regulations) — Institution of Engineering and Technology

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