LV MV HV Voltage – How Are They Defined? Which One Does Your Project Need?

Low Voltage, Medium Voltage, High Voltage – How Are They Defined?
Which One Does Your Project Need?

Introduction

"Should my project use low voltage or medium voltage? What‘s the difference between 10kV and 35kV?"

These are common questions from overseas clients when planning a power distribution project. Voltage levels sound straightforward, but different countries use different classification standards – and that can cause confusion.

This article helps clarify:

• How voltage levels are classified

• The difference between Chinese and international standards

• What voltage levels are used in most projects

1️⃣ Chinese Standard: How Are LV, MV, and HV Defined?

According to Chinese national standard GB/T 156 and related industry regulations, AC voltage levels are generally classified as follows:

Source: Chinese national standard GB/T 156-2007 Standard Voltages

Plain English:

• LV (220V/380V) – directly powers equipment, sockets, and lighting

• MV (10kV/35kV) – the incoming supply for factories, commercial buildings, and residential complexes. This is our core business.

• HV and above (110kV+) – transmission grid, power transfer between substations, not typically delivered directly to end users.

2️⃣ Important Note: International and Chinese Standards Differ

IEC (International Electrotechnical Commission) classification:

According to IEC TS 62749, the globally recognized voltage level classification is as follows:

Source: IEC TS 62749:2020

Key differences from Chinese standards:

• China classifies 1kV–35kV as "medium voltage" and 35kV–220kV as "high voltage"

• IEC classifies anything above 35kV as "high voltage" – without a separate medium voltage sub-category

Example:
A 35kV project is called "medium voltage" in China, but when communicating with international clients, saying "Medium Voltage" works – because IEC defines medium voltage as 1kV–35kV, which aligns with the Chinese classification in this range.

3️⃣ Our Business Scope: Up to 35kV

We cover the following range:

• Low Voltage: 220V / 380V distribution panels, distribution boxes

• Medium Voltage: 10kV, 35kV switchgear, ring main units, transformers

Why we don’t go higher:

• 110kV and above belongs to the transmission grid – manufacturing standards and applications are completely different from customer-side distribution

• These projects require specialized transmission equipment qualifications – not the standard scope of a medium/low voltage equipment supplier

• Most factories, commercial buildings, and residential projects use 10kV or 35kV as their incoming supply

Whatever you need within this voltage range, we can supply. Beyond this range, we recommend consulting a specialized transmission equipment manufacturer.

4️⃣ Which Voltage Do Common Projects Use?

In short: The vast majority of projects fall within 35kV and below – which is exactly our business scope.

Conclusion

• LV: ≤1kV, directly powers equipment

• MV: 1kV–35kV, the incoming supply for factories, buildings, and residential complexes – our core business

• HV: Above 35kV, transmission grid – not our business focus

Chinese voltage classification differs slightly from IEC standards, but the 1kV–35kV medium voltage range is consistent worldwide. If your project falls within this range, we can provide a complete equipment configuration solution.

If you have a specific project and need voltage selection advice, feel free to contact us.

Web: https://yqsxdl.en.made-in-china.com/
Whatsapp：+86 195 1818 9858
Mail: lunahe927@gmail.com/19518189858@163.com