Insulating oil test sets

  • Latest IEC standards
  • IEC60156-2018 and IEC60156-2018 V for viscous oils
  • IEC60156-2018 Annex A and IEC60156-2018 Annex A (V) for viscous oils
  • Withstand tests
  • OTS configurator removed – range consolidated
  • AF 12 variants
  • PB 8 variants
  • Lightweight from 16.8 kg – OTS PB range 60 kV and 80 kV
  • Portable (OTS PB) and Laboratory instruments (OTS AF) range from 60 kV up to 100 kV

The OTS PB and OTS AF insulating oil test sets are a range of automatic oil test sets that perform accurate breakdown and withstand voltage tests on
mineral, ester, and silicone insulating liquids. All models have precision, shatter-proof test vessels that are easy to clean and provide repeatable results, whether they are used in the field or laboratory. They also have a transparent, shielded lid and a large test chamber, giving you easy access to the test vessel and allowing you see what is happening within the test chamber.

Test results are identified either by a serial number or asset ID and are time and date stamped. The units come with PowerDB Lite, Megger's asset and data management software, at no extra cost, giving you an excellent tool for downloading and printing results. They units also have an internal printer, so you can have a hard copy of your results. The instruments also have USB drives for easy transfer of test results and an external USB printer. The AF model also includes a barcode scanner.

These test sets have been designed with your safety in mind so that during a test, you can terminate at any time by pressing any button on the keyboard and this will remove the high voltage immediately and abort the test. The transparent lid also provides ample visibility within the chamber, yet is protected and electrically shielded by a screen with multiple links to instrument ground.

All of the current test standards worldwide are pre-loaded in the instrument for convenient automatic operation, however should a new test standard or an existing standard be amended, there are 3 custom tests that can be configured to the new requirements. This enables testing to continue to cover the short period while Megger updates the test procedure files. New updated files are then downloaded by the user and installed into the test instrument via a USB drive.

OTS PB models

These 60 kV and 80 kV oil test sets are the smallest and the lightest on the market with weight ranging from 16.8 kg to 20.8 kg depending on the model configuration. These units can be mains powered or battery operated for additional flexibility in portable applications and all PBs are fitted with NiMH batteries and are also supplied with an internal12 V DC charger and vehicle adaptor cable as standard. The transport case and carry bag are optional accessories. The carry bag has pouches for electrode accessory pack, leads, quick user guide, paper roll etc.

OTS AF models

These 60 kV, 80 kV, and 100 kV models have a much larger test chamber for even easier access and cleaning, particularly useful in a lab environment. They are fitted with a 12-key alphanumeric keypad to facilitate entry of test ID, file names, notes etc. Alpha characters are entered by repetitive pressing on a key. The AF models also have the ability to use a USB barcode reader to scan oil sample barcode labels, ideal for better integration within a laboratory.

For the latest standards, please contact your local sales team here. They will be able to provide you with the new operating system and instructions on how to upgrade your instrument.

Technical Documents
Technical guide
OTS vessel preparation
Technical guide
Guide to insulating oil dielectric breakdown testing – OTS series
OTS Test Standards


The attached file will update all the test standards of your OTS to the latest versions. Do not change the file name or it will not work. Please follow the instructions below:-


1. Extract the attached file (stdSeqs.db) to a USB memory stick


2. Insert the memory stick into the Type A USB port on the front panel of the OTS (or the Type A USB port on the rear of the OTS)


3. On the OTS, navigate to the Tools menu with the Hammer & Wrench symbol


4. Scroll down and select Manage test standards


5. On the next screen select Update Standards (USB) and the instrument will upload the new file from the USB stick.


6. The instrument will now have the latest standards installed ready to use.


For Older OTS (Firmware version 1.15) use ""


For updated OTS (Firmware version use ""


IMPORTANT NOTE: is not compatible with OTS Firmware version 1.15 is not compatible with OTS Firmware version
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