By LarsonElectronics.com – May 14, 2025

Transmission Voltage Levels

Transmission lines are designed to carry electricity over long distances with minimal loss. These are typically classified as high voltage or extra-high voltage systems:

69 kV – Entry-level transmission voltage
115 kV
138 kV
161 kV
230 kV
345 kV
500 kV
765 kV – Among the highest AC transmission voltages in the U.S.

Sub-Transmission Voltage Levels

These voltages serve as intermediates between high-voltage transmission and medium-voltage distribution. Sub-transmission is common in rural areas and industrial zones:

34.5 kV
46 kV
69 kV

Distribution Voltage Levels

These voltage levels are typically used for delivering power from substations to commercial, industrial, and residential areas. While some may classify them as medium voltage, they are often referred to as high voltage within distribution networks:

4.16 kV (4160 V)
12.47 kV
13.2 kV
24.9 kV
34.5 kV

Industrial High Voltage Applications

Large industrial operations often utilize higher voltages to power motors and heavy machinery. These systems demand robust electrical infrastructure:

4160 V – Frequently used in manufacturing plants
13.8 kV – Common in major industrial facilities

High Voltage Direct Current (HVDC) Systems

HVDC is used for long-distance, high-efficiency transmission and for connecting asynchronous power grids:

±500 kV – Common for long-range, high-capacity transmission
±800 kV – Used for ultra-long distances and major energy corridors

Voltage Classifications (Based on IEEE and NESC Standards)

Classification	Voltage Range
Low Voltage	600 V or less
Medium Voltage	601 V to 69 kV
High Voltage	69 kV to 230 kV
Extra-High Voltage (EHV)	230 kV to 765 kV
Ultra-High Voltage (UHV)	Above 765 kV

Need help identifying the correct high voltage configuration for your operation?

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