Dianoush Emami is an electrical engineer with 30 years of experience developing high-voltage electrical systems. There is no universally agreed upon definition of what constitutes a high-voltage system, but definitions generally depend on industry standards and safety risks. The National Electric Code defines high voltage as anything over 100 volts that can harm a person, while outside the US high voltage is considered 600 volts or more, with low voltage being 120 volts or less.

1. WHAT
CONSTITUTES A
HIGH-VOLTAGE
ELECTRICAL
SYSTEM?
DIANOUSH EMAMI

2. INTRODUCTION
• An electrical engineer in California, Dianoush Emami has been
involved in several power-generation and electrical substation
projects throughout his 30-year career. Dianoush Emami was
responsible for developing a human-machine interface for the
systems at Avista, performing a technical audit for the California
Independent System Operator, and designing and installing
various high-voltage electrical systems.
Defining “high-voltage” is often difficult since there is no
universally accepted definition. According to Merriam-Webster,
high-voltage means “marked by great energy.” Collins Dictionary
in the United Kingdom states that high-voltage systems are over
1,000 volts.

3. HIGH-VOLTAGE
• Usually, defining high-voltage is dependent on industry standards,
but even these vary to some extent. The National Electric Code (NEC)
standards defines high voltage (HV) as anything above 100 volts that
is capable of causing harm to a person.
Low voltage systems, meanwhile, are often below 100 volts and have
a lower risk of injury. These definitions relate to domestic usage only
and are usually the definitions followed by electrical professionals in
the United States.
However, outside of the US, the ranges also change. On average, low
voltage systems are 120 volts or less, while high voltage systems are
at least 600 volts.