Better Industry Testing Standards and What That Means for You
Overview
SDMyers now recommends ASTM D1816 over the traditional D877 dielectric test for power equipment liquid screening—here’s why the change matters and what it means for your testing package.
How SDMyers Is Improving Dielectric Breakdown Voltage Testing
For several years, SDMyers included ASTM D877 as the dielectric test for power equipment in our liquid screen test package. In recent years, organizations including IEEE and ASTM compared D877 to another dielectric test, ASTM D1816, and found that D1816 provides more accurate results for evaluating the dielectric characteristics of liquid inside power equipment. As a result, SDMyers now recommends D1816 over D877.
What Is Changing, and Why?
SDMyers now recommends ASTM D1816 as the standard dielectric test for electric power equipment owners. There are three primary reasons for this transition:
- Improved sensitivity and technical accuracy — The electrodes in the D1816 test are more responsive to particles and dissolved water in oil, providing a better evaluation of changes that may occur in transformer oil.
- Better representation of transformer characteristics — The flat disk electrodes in D877 do not accurately represent the dielectric environment inside transformers and other power equipment. The rounded electrodes in D1816 more closely resemble real-world transformer applications.
- Industry acceptance — As the science of our industry has advanced, so has SDMyers’ testing. D1816 has become the most widely accepted dielectric test, supported by real-world application results and the expertise of power professionals worldwide—including our own team at SDMyers.
This change reflects our ongoing commitment to delivering the best value to our customers and maximizing the reliability and safety of your electrical power equipment.
What Are the Differences Between D877 and D1816?
Both are standard methods from ASTM International. D877 is the Standard Test Method for Dielectric Breakdown Voltage of Insulating Liquids Using Disk Electrodes. D1816 is the Standard Test Method for Dielectric Breakdown Voltage of Insulating Oils of Petroleum Origin Using VDE Electrodes. The table below outlines the key differences between the two standards.
| ASTM D877 | ASTM D1816 | |
|---|---|---|
| Types of electrodes | Disk | VDE |
| Electrode gap | 2.54 mm | 1 or 2 mm |
| Stirring | None | Continuous |
| Voltage rate of rise | 3 kV/s | 0.5 kV/s |
| Breakdown value | Mean of 5 measurements | Mean of 5 measurements |
What Does This Mean for You?
SDMyers customers can request either dielectric test—D877 or D1816—as part of their testing package. Your SDMyers contact can walk you through the differences in more detail and help determine which option is the best fit for your equipment and goals.
We are committed to delivering value to electrical power system owners in a way that continuously improves and advances with industry expectations. A key part of that commitment is ensuring our results and testing recommendations reflect the highest technical accuracy available—so you can have confidence that your results are reliable, actionable, and supportive of your assets’ long-term health.
