What is Voltage Rating?

Malcolm Tatum
Malcolm Tatum

A voltage rating is an evaluation based on research and experimentation that help determine how much voltage can be safely utilized by a particular device or form of wiring over the life of the device or wiring. For electrical and electronic devices, this rating is determined during product development and testing by increasing the voltage levels until the devices break down or begin malfunctioning. The voltage rating is not the maximum at which breakdown occurs, it is a percentage of the maximum and is intended to be a safe level for extended use. For wiring, the voltage takes into consideration the materials used to construct the wiring, the thickness of wires and the intended use of the wiring. A voltage rating scale has been established for all forms of electrical wires.

Wiring that is used in the electrical system of a residential home must meet a specific voltage rating.
Wiring that is used in the electrical system of a residential home must meet a specific voltage rating.


The main purpose of a voltage rating is to ensure that the user of the wiring or the device can reasonably expect to use the material for its intended purposes and not encounter danger to the user or damage the device. From this perspective, the rating will specify how much electrical current can safely be carried through the wiring, and it will define the type of current that can be safely conducted through the wire. Following the standard set by the voltage rating greatly diminishes the chances of overheating and electrical fires.


There is no commercially manufactured device that has not been tested and certified with a voltage rating. Depending on the construction and intended use of the device's wiring, the rating could vary greatly. For example, voltage ratings for mineral-insulated (MI) copper cable usually is close to 1,000 volts. The wiring for table lamps and other small household appliances usually is much lower.

Safety Standards

By setting a rating that specifies the highest voltage that the wiring can carry and still operate within acceptable safety limits, governments and other organizations can set standards for wiring depending on its applications. Wiring that is used in the electrical system of a residential home, for example, typically must meet specific standards and be within a certain range. The same is true for wiring in public buildings. Many types of machinery used in the production of goods and services must also contain wiring that meets standards and have a voltage rating that is considered reasonable for the level of current that the machine will need to function properly over the long term.

Malcolm Tatum
Malcolm Tatum

After many years in the teleconferencing industry, Michael decided to embrace his passion for trivia, research, and writing by becoming a full-time freelance writer. Since then, he has contributed articles to a variety of print and online publications, including EasyTechJunkie, and his work has also appeared in poetry collections, devotional anthologies, and several newspapers. Malcolm’s other interests include collecting vinyl records, minor league baseball, and cycling.

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Discussion Comments


What is the voltage rating of an electric stove?


To the light bulb question. You answered your own question there. The light bulb is rated for 12V. If you need an equation to justify an answer, take the wattage (50 watts) divide it by the amperage (4.17 amps) and you'll get 11.99, so 12 Volts is your answer.


please give me a clear idea about amps, kilovolts, kilovolt amps and watts.


i have a 50 watt light designed for recreational vehicles (12V) and it draws a current of 4.17 amps. What is the approximate voltage rating of the light bulb?


I have equipment rated 400v. can I connect it to a 440 or 460 volts supply or do i need a transformer that will produce exactly 400 volts.


If voltage rating is the stress of voltage on the size wire or fuse. And it is the load (or current)that creates the heat, plus the factors of ac vs. dc. Then I should be able to send 120 volts across a automotive fuse (or Fuseholder rated for 24 volts) with a 2 amp fuse and less than a 2 amp load. So why "voltage rating"?


what is 0.6/1kv?


The article is a little confusing. The current rating is based on the size of copper wire used and the voltage rating is the maximum amount of stress the cable insulation can take. (Dielectric Strength)

208V is three phase and 240V single phase three wire (two hots)


I think it is the rated voltage of the cable i.e uo/u


Are you seriously asking this?


I have a cable rated 150/250V

Is the 150 single phase and the 250 three phase?

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