The Fascinating Connection: Decoding the Mystery Behind Multiples of 11 in Transmission Voltage

Have you ever wondered why most of the transmission voltage is a multiple of 11? This seemingly random number is actually a result of careful engineering and design. The choice of 11 as a base number for transmission voltage is not arbitrary, but rather a result of practical considerations and historical precedents. This article will delve into the fascinating connection between multiples of 11 and transmission voltage, decoding the mystery behind this intriguing pattern.

The Origin of the 11kV System

The 11kV system, or 11,000 volts, is a standard in many countries for electricity transmission. This standard originated in the UK, where the first public electricity supply was established. The choice of 11kV was a compromise between the need for high voltage to transmit power efficiently over long distances, and the need to limit the voltage to a level that could be safely handled with the technology available at the time.

Why Multiples of 11?

The choice of 11 as a base number is not arbitrary. It is a result of the way electrical systems are designed and manufactured. Electrical equipment, such as transformers and generators, are often designed to operate at voltages that are multiples of 11. This is because these voltages are easier to produce and control with the materials and technology available. Additionally, using multiples of 11 allows for a consistent and standardized system, which simplifies design, manufacturing, and maintenance processes.

The Role of Safety and Efficiency

Safety and efficiency are two key considerations in the design of electrical systems. High voltages are more efficient for transmitting power over long distances, as they reduce power loss due to resistance. However, high voltages also pose a greater risk of electrical shock and equipment damage. Therefore, a balance must be struck between efficiency and safety. The 11kV system, and its multiples, provide a good balance between these two factors.

As technology advances, the standard transmission voltages may change. However, the principles of safety and efficiency will always be paramount. Therefore, it is likely that future transmission voltages will continue to be multiples of 11, or some other base number that provides a good balance between safety and efficiency.


The connection between multiples of 11 and transmission voltage is a fascinating example of how engineering and design decisions are influenced by practical considerations and historical precedents. It is a reminder that even seemingly arbitrary patterns can have a logical explanation. So, the next time you see a transmission line, remember the careful thought and planning that went into its design.