hello friends ,

in this article i will tell about different levels of electrical voltages....... 

1. Extra low voltage range.
2. Low voltage range.
3. Medium voltage range.
4. High voltage range.
5. Extra high voltage range.
6. Ultra high voltage range.

these above all six levels of voltages generally used in electrical systems......

1) extra low voltage also be stand as ELV .....

 ELV circuit as one in which the electrical potential of any conductor against earth (ground) is not more than either 25 volts RMS for alternating current, or 60 volts for direct current.

i put one chart for better understanding 

you also can download that handmade chart for reference......

above charts gives all voltage range declared by IEC and BS standard 

THANK YOU ...