Solar wiring and connection issues: a hidden performance killer — UK

Loose connectors, corroded terminals, and damaged wiring cause resistive losses that silently drain your system's output. Unlike other faults, wiring issues can also be a fire risk. Here's what to watch for and why you should never attempt DIY wiring repairs. This guide is tailored for UK solar owners, where maritime climate conditions and shorter daylight hours create different challenges.

Symptoms to watch for

Signs that this issue may be affecting your system

Wiring or connection issues

Uncommon

Loose connectors, corroded terminals, or damaged wiring causing resistive losses. Can be a fire risk if severe.

Loss: 3–20%Detection: electrical

When to get a professional inspection

Signs you need professional help

-Your system is over 7 years old and you've noticed a production decline
-Production has dropped more than 1% per year compared to year one
-Your system has experienced hail, storms, or physical damage
-You see visible damage: discolouration, bubbling, or cracked glass
-Your inverter shows frequent error codes or unexpected shutdowns

Expected inspection costs

Drone thermal audit

Most comprehensive option

Handheld thermal scan

Best for smaller systems

Electrical inspection

Inverter and wiring only

Find inspection providers

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Is your system affected?

Use our free Solar Loss Checker to get a personalised diagnosis with an action plan.

Check my systemShould I get an audit?

Based on conservative solar performance modelling and published degradation data

NRELIEA-PVPSSunSpecPVsyst+ published research

Updated April 2026 · Structured performance modelling

How we calculate →

More guides

→Why Are My Solar Panels Underperforming?→Solar Panel Hotspots Explained→Is Your Solar Inverter Losing Efficiency?→How Dirt and Soiling Reduce Solar Panel Output

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