On the basis of different criteria, electrical voltages can be classified into many classes based on different standards. A general classification of voltage classes and range is shown below:
| Voltage Class | Range |
| Extra-low voltage | 0 – 50 kV |
| Low voltage | 50 V – 1 kV |
| Medium voltage | 1 – 35 kV |
| High voltage | 35 – 245 kV |
| Extra high voltage | >245 kV |