# Thread: What is HV,MV and LV

1. Senior Member
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## What is HV,MV and LV

Kindly define the voltage range of High Volt (HV), Medium Volt(MV) and Low volt (LV)?

2. Originally Posted by vinod
Kindly define the voltage range of High Volt (HV), Medium Volt(MV) and Low volt (LV)?
There really is no definition of those terms. Low voltage can mean 24 volts if you are referencing 120 volts ot it can be 240 volts if your reference for high volts is 480.

The NEC does not define it. What are you specifically looking for.

The NEC oftens has articles that refer to 600 volts or less and others that say over 600 volts but that is not a definition of voltages.

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## range

As far as I know that,

LV is <600V
MV is >600V to <38KV
HV is >38KV to <115 KV
Extra HV is >115KV

Am I correct?

4. Originally Posted by vinod
As far as I know that,

LV is <600V
MV is >600V to <38KV
HV is >38KV to <115 KV
Extra HV is >115KV

Am I correct?
Where, may I ask, are you referencing this info from?

5. This is from Wikkipedia

In electric power transmission engineering, high voltage is usually considered any voltage over approximately 35,000 volts. This is a classification based on the design of apparatus and insulation.
The International Electrotechnical Commission and its national counterparts (IET, IEEE, VDE, etc.) define high voltage circuits as those with more than 1000 V for alternating current and at least 1500 V for direct current, and distinguish it from low voltage (50–1000 V AC or 120–1500 V DC) and extra low voltage (<50 V AC or <120 V DC) circuits. This is in the context of the safety of electrical apparatus.
In the United States 2005 National Electrical Code (NEC), high voltage is any voltage over 600 V (article 490.2). Laypersons may consider household mains circuits (100–250 V AC), which carry the highest and most dangerous voltages they normally encounter, to be high voltage. For example, an installer of heating, ventilation and air conditioning equipment may be licensed to install 24 Volt control circuits, but may not be permitted to connect the 240 volt power circuits of the equipment.
Voltages over approximately 50 volts can usually cause dangerous amounts of current to flow through a human being touching two points of a circuit, so safety standards generally are more restrictive where the chance of contact with such high voltage circuits exists.
In digital electronics, a high voltage is the one that represents a logic 1 (1.1–5 V).

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Sir
Thank you very much for your explenation.
I am working as a electrical substation technician.

7. Per IEEE:

LV < 600V
MV 601-69kV
HV 69kV-230kV
EHV 230kV- 800kV
UHV >800kV

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Thank you Sir

This is what I am really looking for....

Thanks a lot.... Mr.Zog

9. Originally Posted by vinod
Kindly define the voltage range of High Volt (HV), Medium Volt(MV) and Low volt (LV)?
It is best to go to an authorotive source. (Wikipedia may be right but it is NOT and authority.)

IEEE Std. 141 also known as the Red Book
120-600V Lov Voltage
2400-69000 Medium Voltage
115000-230000 High Voltage
345000-765000 Extra High Voltage

(This way you can cite the authority, not Jack from the Mike Holt Forum....)

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Funny that; IEEE is an international authority, but the 110KV lines we have here in NZ dont fit into any official category....

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