IEEE 4-1940

4-1940 is a superseded AIEE standard titled Standards for Measurement of Test Voltage in Dielectric tests, focused on how test voltage should be measured during dielectric testing. It is relevant to power, energy, and industrial electrical work where insulation performance must be assessed with care. By defining measurement expectations for test voltage, this document helps support more consistent testing outcomes, clearer comparison of results, and better control of dielectric evaluation practices.

Overview of 4-1940

This technical standard addresses the measurement of test voltage used in dielectric tests, a key part of evaluating insulating materials, components, and electrical assemblies. 4-1940 sits within a testing context where accuracy in voltage measurement affects the reliability of insulation assessments and related engineering decisions. For users handling high-voltage or insulation test procedures, the document provides historical guidance on a specific measurement practice rather than a general design code.

Typical use cases

Typical use cases include dielectric testing of electrical components, insulation systems, and engineered materials where the applied test voltage must be measured and recorded consistently. It may be consulted in laboratory test workflows, equipment qualification, and review of older test methods for power and industrial applications. The standard is also useful when comparing legacy test procedures or interpreting documentation tied to AIEE-era measurement practices in dielectric testing.

Why it matters

Measurement details can significantly affect dielectric test results, so a document like 4-1940 matters for consistency, traceability, and risk reduction. Accurate voltage measurement supports fair comparison between tests, helps avoid misinterpretation of insulation performance, and improves confidence in compliance records. For organizations maintaining legacy procedures or evaluating older equipment documentation, it can also provide important context for how test voltage was intended to be measured.

• Dielectric test voltage measurement
• Insulation and materials testing context
• Legacy AIEE technical guidance
• High-voltage test consistency
• Superseded historical standard