What is PID (Potential Induced Degradation)?
A fault where stray voltage gradually drains a panel's output over time, mostly affecting older panel designs.
Quick Answer
PID is rarely a problem for quality panels installed in the UK today, as reputable manufacturers build in PID resistance and test to IEC standards. It is more a consideration when assessing older systems or very cheap, unbranded panels. Choosing a reputable brand and MCS-certified installer effectively removes the risk.
Fact-checked by John Rooney, Solar Energy Editor. Editorial policy
PID (Potential Induced Degradation) Explained
PID (Potential Induced Degradation) is a performance loss caused by stray currents leaking between a panel's cells and its frame, driven by the voltage difference between the panel and earth. Over months or years it can cut a panel's output significantly. It is more common in humid conditions and in older or lower-quality panels. Modern N-type panels and PID-resistant designs largely avoid it, and quality manufacturers test against IEC PID standards.
How Does PID (Potential Induced Degradation) Work in the UK?
PID is rarely a problem for quality panels installed in the UK today, as reputable manufacturers build in PID resistance and test to IEC standards. It is more a consideration when assessing older systems or very cheap, unbranded panels. Choosing a reputable brand and MCS-certified installer effectively removes the risk.
Frequently Asked Questions
What causes potential induced degradation?
PID is caused by stray leakage currents between the solar cells and the panel frame, driven by the voltage difference to earth and worsened by heat and humidity. It gradually reduces output, mainly in older or lower-quality panels.
Should I worry about PID on a new UK system?
Generally no. Reputable manufacturers build PID resistance into modern panels and test to IEC standards. PID is mainly a concern for older systems or very cheap unbranded panels. A quality brand fitted by an MCS-certified installer avoids it.
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John Rooney is the founder of Solar Info and has been covering the UK solar energy market since 2023. He researches every battery and inverter brand against manufacturer datasheets, MCS and Ofgem data, and feedback from the MCS-certified installers in our directory before publishing.