Exhibitor News

👉 600V Is No Longer Enough – Are You Ready for 1500V PV Testing?

Solar PV Testing for the Next Generation of High Voltage Systems

The rapid evolution of solar photovoltaic technology is bringing both greater efficiency and new challenges for installers and electrical contractors. As module efficiency improves, the voltage characteristics of PV strings are increasing, with open circuit voltage (VOC) regularly exceeding the traditional 600V range that many standard clamp meters were originally designed to measure.

For today’s installer, this shift is not just a technical detail – it directly impacts safe working practices, correct equipment selection, and ultimately compliance. This is where purpose-built Solar PV test kits such as the Di-LOG SL350 and the newly launched SL550 are becoming essential tools on site.

The Move Beyond 600V – Why It Matters

Higher efficiency panels mean more modules can be connected in series, delivering greater system output. However, this inevitably pushes string voltages upwards. Modern installations are increasingly operating at 1000V DC, and in larger commercial and utility-scale applications, 1500V DC systems are now becoming commonplace.

The move towards 1500V DC systems aligns with wider industry design practices and safety frameworks, including the requirements surrounding PV power systems and equipment safety outlined in IEC 62109, which addresses protection against electrical hazards in high voltage environments.

“IEC 62109 is an international safety standard ensuring that photovoltaic power converters are designed and tested to safely withstand high‑voltage conditions, including applications aligned with CAT III 1500V systems protecting against electric shock, fire, and mechanical hazards.”

For contractors, the implication is clear: test equipment must be capable of safely and accurately measuring higher voltages, particularly when verifying open circuit voltage during commissioning or fault finding.

SL350 – Practical Testing for Domestic and Commercial Installations

The Di-LOG SL350 Professional Solar PV Test Kit has been designed to provide installers with a comprehensive yet accessible solution for everyday PV testing.

At the core of the kit is the DL6414 True RMS AC/DC clamp meter, capable of measuring voltages up to 1000V AC/DC. This allows safe verification of high VOC values typically encountered in larger domestic and medium-scale commercial installations.

Complementing this is the SL104 Solar Irradiance Survey Tool, which enables accurate measurement of irradiance, array direction, roof pitch and, importantly, panel temperature. The inclusion of both internal and external temperature probes ensures compliance with IEC 62446-1 requirements for PV system testing, including cell temperature measurement.

For installers, the benefit is clear: the SL350 brings together electrical and environmental measurements in one compact kit, reducing the need for multiple instruments and streamlining the commissioning process.

Introducing the SL550 – Meeting High Voltage Demands

With the continued shift towards higher voltage PV systems, the newly launched Di-LOG SL550 Advanced Solar PV Test Kit has been developed to support the next generation of installations.

While the SL350 comfortably supports systems up to 1000V DC, the SL550 is positioned to address the growing requirement for testing at 1500V DC. This is particularly relevant for larger commercial and industrial projects, where higher system voltages are now standard practice.

A key differentiator of the SL550 is the inclusion of Di-LOG’s new flagship clamp meter, the DL6415. Rated CAT III 1500V, this advanced instrument has been designed specifically for modern high-voltage PV applications conforming to IEC 62109, providing installers with the confidence to work safely and accurately on higher energy systems.

Beyond voltage and current measurement, the DL6415 delivers a significantly enhanced feature set, including Power and Energy measurement, Harmonics analysis, and Bluetooth connectivity. This allows contractors not only to verify electrical parameters, but also to gain deeper insight into system performance and share or record data more efficiently.

For contractors working in this space, having test equipment that matches system voltage ratings is not just about capability – it is about safety, compliance, and confidence on site. The SL550 ensures installers are equipped for modern PV architectures, reducing risk while also expanding diagnostic capability.

A Practical Approach for Today’s Installer

For larger installations operating at higher voltages, the SL550, complete with the advanced DL6415 clamp meter, ensures safe and effective testing aligned with modern PV system demands, while also providing enhanced measurement and reporting capability.

Beyond Basic Testing – Full PV System Verification

While solar PV kits such as the SL350 and SL550 provide essential tools for installation and maintenance, full system verification often requires dedicated PV testers.

Di-LOG also supplies the Seaward PV:1525 Series, a comprehensive handheld test solution capable of performing electrical safety tests and performance measurements on PV systems up to 1500V DC and 25A. These instruments support key commissioning tests, including open circuit voltage, short circuit current, insulation resistance, and continuity.

For more advanced diagnostics, the PV:1525-IV model adds I-V curve tracing, enabling installers to assess system performance and identify faults beyond basic electrical checks.

By offering both solar PV test kits and advanced PV testers, contractors can scale their testing capability depending on project size and complexity.

For electrical contractors looking to stay ahead of evolving PV system demands, having the right test equipment is essential. Whether you are working on domestic installations or high voltage commercial projects, Di-LOG offers practical, future-ready solutions to support safe and compliant testing. To explore the full range of Solar PV test kits and solutions, visit www.dilog.co.uk/pv  or speak directly to the team on 0161 877 0322 for expert advice and support tailored to your next project.

David Sweetman

Managing Director – Commercial

Di-LOG Group

June 2026