# Difference Between High Voltage and Low Voltage

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## Difference Between High Voltage and Low Voltage

What is the difference between high voltage and low voltage ?

Let us understand it in details.

Any voltage used on board a ship ,if less than 1kv (1000 v) then it is called as lv ( low voltage ) system and any voltage above 1kv is termed as high voltage.

As Per IEC Standards,voltages less than 1000 (1 kv ) voltage is classified as low voltage.

And voltages greater than (245000 v )245kv is classified as high voltage according to IEC.

What is classed as high voltage ?

In marine field,

Voltages below (less than ) 1,000 vac (1kv ) are considered low voltage, and

voltages above 1kv is High Voltages.

Typically, high voltages kn board are 3.3 kvs,6.6 kvs and 11 kvs.

## The major difference between high voltage supply and low voltage supply on board ship are :-

1.High voltage system as compare to low voltage are more extensive with complicated networks and connections.

2.Isolated Equipment used must be earthed down.

3.Entry to high voltages area will be strictly restricted and controlled.

4.Isolation process are more involved.

5.Switching strategies need to be formulated and recorded.

6.It is necessary to use specific high voltage test probes and instruments.

7.It is necessary to test Diagnostic insulation resistance.

8.High voltages systems are normally earthed neutral and uses such resistors which limit current.

9.There is need to be installed Special high voltage circuit breakers.

Definition of low voltage ( LV ), medium voltage (MV ), high voltage (HV ) and extra high voltage (EHV ) vary somewhat but, a general guide for categories voltage are as follows :-

1.Low Voltage (LV ):- Up to 1000V

2.Medium Voltage (MV ):-   between  1000 V and 35000 V (35 kV )

3.High Voltage (HV ):- Voltage  between   35 kV and 230 kV

4.Extra High Voltage (EHV ) :- Voltage from  230 kV and above.

Low Voltage,Medium voltage,high voltage and Extra high voltage classifications:-

The Voltage Range of LV, MV,HV and EHV are:-

1.Low Voltage
Voltage rating used in the LV (Low Voltage) is 50 Volts-1000Volts (1KV)
50V < Low Voltage <1000 V

2.Medium Voltage

Voltage range used in the MV (Medium Voltage) is 1000Volts (1KV) to 35,000Volts (35KV)

1KV < Medium Voltage < 35KV

3.High Voltage
The voltage range used in the HV (High Voltage) is 35,000Volts (35KV) to 245,000Volts (245KV)

35KV < High Voltage < 245KV

4.Extra High Voltage

The voltage range used in the EHV (Extra High Voltage) is > 245,000 Volts.

EHV > 245KV