Low-voltage switchgears - Fuse-switch-units - DO-System; Corrigendum 1
2Expert Interpretation
This article provides an in-depth analysis of the revised DIN VDE 0638 document, released in December 2018, focusing on the updated requirements for the 220/380V to 400/230V voltage standards. It covers the technical background, implementation impacts, and compliance recommendations, providing guidance for electrical engineers on standard implementation.
Standard Revision Background and Technological Evolution
DIN VDE 0638 Berichtigung 1 (VDE 0638 Amendment 1), published in December 2018, is a major technical revision of the DIN VDE 0638 standard, originally published in September 1981. Maintained by the UK 541.1 "Fuses and Switch-Fuse Units" working group under the German Commission for Electrical, Electronic and Information Technology (DKE), this standard is a key component of the VDE normative system.
The core of this revision is the standardization of all references to 220/380V AC voltages to 400/230V. This change applies not only to the main standard itself but also to all related referenced standards. From a technological perspective, this revision reflects the modernization of European grid voltage standards and aligns them with International Electrotechnical Commission (IEC) standards.
Detailed Explanation of Key Technical Changes
The revised document explicitly mandates that all references to "220/380V" AC voltage in DIN VDE 0638:1981-09 should be replaced with "400/230V." This voltage standard update has significant technical significance:
The 400/230V voltage system complies with the low-voltage power supply voltage standards specified in European standard EN 60038, where 400V refers to line voltage and 230V to phase voltage. Compared to the existing 220/380V system, the new standard better aligns with the actual operating parameters of modern power systems, improving equipment safety and compatibility.
| Parameter type | Original standard value | Corrected value | Change range |
|---|---|---|---|
| Phase voltage | 220V | 230V | +4.5% |
| Line voltage | 380V | 400V | +5.3% |
| Voltage level | Old European standard | Current international standard | Standard unification |
Low voltage switchgear220V 230V +4.5% Line voltage 380V 400V +5.3% Voltage level Old European standard Current international standard Standard unification
Low voltage switchgear Impact Analysis on Fuse Switch Units: This revision of the voltage standard directly impacts the design, manufacturing, and inspection requirements for low-voltage switchgear and fuse switch units. As the standard applies to DO systems, related equipment must adapt to the new voltage parameters: Equipment insulation performance requirements must be adjusted accordingly, particularly with changes to the design reference voltage for clearances and creepage distances. Fuse breaking capacity verification must also be conducted based on the new voltage standard to ensure safe interruption performance in 400/230V systems. In a practical application case, a German manufacturer conducted a conformity assessment of existing fuse switch units and found that while most products met the new voltage requirements, the insulation materials of some older models required upgrading to withstand the higher voltage stresses.
Standard Implementation Recommendations and Compliance Measures
Standard Implementation Recommendations and Compliance Measures
To ensure a smooth transition to the new voltage standard, the following implementation measures are recommended:
First, all users of the relevant standards should indicate this revision in the affected standard text to ensure the correct voltage parameters are used during project design and equipment selection.
Second, equipment manufacturers should re-evaluate their product designs, particularly the voltage withstand capability of their low-voltage switchgear, and conduct type testing where necessary. For equipment already in use, its suitability under the new voltage standard should be assessed, particularly with regard to the risk assessment of equipment with aging insulation.
Finally, engineering designers should uniformly adopt 400/230V as the reference voltage value when designing systems to ensure that both new and retrofit projects comply with the latest standard requirements.
Technical Background and Standard Coordination Analysis
This revision reflects the progress towards harmonization of voltage standards across Europe. As early as the 1990s, the European Committee for Standardization (CEN) began promoting the harmonization of voltage standards, aiming to eliminate technical barriers between countries and promote the market distribution of electrical equipment. The 400/230V voltage system has become the mainstream standard in EU member states, fully consistent with the international standard IEC 60038. This revision of DIN VDE 0638 is a concrete manifestation of the alignment of German standards with international standards, ensuring the competitiveness of German-made fuse switch units and low-voltage switchgear in the global market. From a technological perspective, higher voltage levels improve power transmission and distribution efficiency, reduce line losses, and reserve sufficient capacity to meet future electricity demand growth. This is why most countries around the world are trending towards higher voltage levels in low-voltage distribution systems.