VLF Withstand Testing

Our VLF withstand testing solutions help you verify the condition of MV and HV cables quickly and reliably. From commissioning to diagnostics, Megger gives you the tools to prevent failures, reduce downtime, and keep your network running safely.

Unreliable cable networks lead to unplanned outages, costly downtime, and reputational risk. VLF withstand testing helps you catch insulation issues before they become failures — giving you the confidence to make data-driven maintenance decisions.

Megger’s VLF solutions support both MV and HV applications and go far beyond simple pass/fail testing. With integrated diagnostics like Tan Delta, partial discharge, and sheath testing, you can pinpoint degradation, verify repairs, and fully commission new installations.

Every product is built for efficient field use, combining portable design with modern automation to speed up workflows and reduce manual error.

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All-in-one cable testing and diagnostics

Commissioning or diagnosing cables often requires multiple tests — and multiple instruments. Megger’s VLF SINE systems simplify that. One platform gives you everything you need for a complete view of cable health across MV and HV networks. With the VLF SINE range and optional PD couplers (PDS 62-SIN or PDS 60-V3), you can carry out withstand testing, oversheath testing, and partial discharge (PD) diagnostics — all using one flexible system. For deeper condition insight, built-in Tan Delta (TD) testing helps identify early-stage insulation ageing. Results are automatically interpreted using the latest IEEE 400.2 standard, giving you clear, consistent data with no guesswork. Whether you're verifying new cable installations or assessing ageing assets, Megger’s all-in-one solution saves time, reduces complexity, and puts complete control in your hands — without needing separate instruments or external software.

Lightweight, powerful, built for the field

Field testing can be demanding — especially when equipment is bulky, heavy, or underpowered. The Megger VLF SINE series is engineered to overcome those limitations. It’s the lightest high-performance VLF tester in its class, making it easy to move between sites, carry into hard-to-reach areas, and set up with minimal effort. You don’t need two people or a trolley — just one reliable unit that’s ready when you are. But portability doesn’t mean compromise. The VLF SINE range delivers the power needed for testing longer cable runs and higher-voltage networks, giving you full flexibility without upsizing your equipment. Whether you’re working in substations, wind farms, or remote industrial locations, Megger gives you the muscle to get the job done — without the weight.

Simple to use — even in the toughest environments

Electrical testing shouldn't be complicated. Megger’s VLF systems are built with the user in mind — combining intuitive operation with smart design features that make testing faster, clearer, and more consistent across your team. With touchscreen interfaces, guided workflows, and built-in automation, our systems reduce setup time and eliminate guesswork. This means fewer training requirements, less chance of error, and greater confidence in your results — whether you're an experienced engineer or new to VLF testing. Menus and reports are available in multiple languages, and tests are easy to repeat across different sites, helping to standardise procedures and improve documentation quality. From first-time users to seasoned technicians, Megger makes it easy to test right the first time — so you can stay focused on the outcome, not the interface.

Complete control of your test data

Efficient testing doesn’t end with a pass or fail — it depends on how easily you can store, access, and act on your results. Megger’s VLF systems put data control at your fingertips, without the need for external devices or complicated workflows. Built-in memory and wireless connectivity allow you to save, export, and share results directly from the instrument. Whether you’re archiving for compliance, generating reports, or comparing trends over time, you can do it all in the field — with no external PC required. MeggerBook Lite software makes post-test analysis fast and frustration-free. It lets you create standardised reports, track condition changes, and manage your test history across teams and sites. The result? Smoother workflows, better traceability, and complete confidence in your cable assessments — from first test to final report.

Frequently Asked Questions

Which product should I use for my application?

Your choice depends on the maximum test voltage and the cable length or insulation level.

VLF SINE 37 – ideal for typical MV distribution cables (up to 15 kV class).
VLF SINE 45 – ideal for typical MV distribution cables (up to 25 kV class). When combined with the VLF CR-40-TB best suited for long cables.
VLF SINE 62 – ideal for typical MV distribution cables (up to 35 kV class).
TDS 40/ TDS 60 – ideal for typical MV cables up to 20/36 kV class as per relevant IEC standard.

All models deliver the same core test capabilities. Not sure which one fits your network? Contact us for tailored advice.

What software do Megger’s VLF products use?

Megger’s VLF systems support a wide range of cable testing needs, including:

Commissioning of new installations
Condition assessment of ageing cables
Sheath integrity testing and fault pinpointing
Tan Delta and offline partial discharge diagnostics (with optional coupler)

They’re ideal for utilities, renewables, and industrial sites — anywhere cable reliability matters.

Can the VLF Sine Series perform partial discharge testing?

Yes — all VLF Sine models can perform offline partial discharge (PD) testing when used with the PDS 62-SIN coupler.

This enables you to detect insulation defects before failure, giving you deeper diagnostic insight beyond standard withstand tests. It's a powerful tool for teams focused on proactive asset management.

Can the TDS 40/ TDS 60 perform partial discharge testing?

Yes – all TDS models can perform offline partial discharge (PD) testing when used with the PDS 60-V3 coupler. Either with DAC Damped AC voltage, or VLF CR voltage, the Megger recommended test voltages for PD testing/ diagnosis. This enables you to detect insulation defects before failure, giving you deeper diagnostic insight beyond standard withstand tests. It's a powerful tool for teams focused on proactive asset management.

What applications are Megger’s VLF products suitable for?

Megger’s VLF systems support a wide range of cable testing needs, including: