Before revision: For example medium voltage can be defined as 1 to 75 URL ultra high voltage (UHV) can be defined as AC voltages of or over 1000 KV and DC voltages of or over 750 URL according to the Society of Automotive Engineers (SAE), low voltage is under 30 volts, medium voltage is 30 to 60 volts and high voltage is over 60 URL and according to the National Electrical Code (NEC) in the USA, voltages of up to 30 volts AC or 60 volts DC are considered low voltage, and voltages higher than these are considered high voltage.National Electrical Code (NEC), NFPA 70, URL Primary distribution Primary distribution voltages range from 4 kV to 35 kV phase-to-phase (2.4 kV to 20 kV phase-to-neutral) Only large consumers are fed directly from distribution voltages; most utility customers are connected to a transformer, which reduces the distribution voltage to the low voltage "utilization voltage", "supply voltage" or "mains voltage" used by lighting and interior wiring systems.
After revision: used in buildingsFor example medium voltage can be defined as 1 to 75 URL ultra high voltage (UHV) can be defined as AC voltages of or over 1000 KV and DC voltages of or over 750 URL according to the Society of Automotive Engineers (SAE), low voltage is under 30 volts, medium voltage is 30 to 60 volts and high voltage is over 60 URL and according to the National Electrical Code (NEC) in the USA, voltages of up to 30 volts AC or 60 volts DC are considered low voltage, and voltages higher than these are considered high voltage.National Electrical Code (NEC), NFPA 70, URL Primary distribution Primary distribution voltages range from 4 kV to 35 kV phase-to-phase (2.4 kV to 20 kV phase-to-neutral) Only large consumers are fed directly from distribution voltages; most utility customers are connected to a transformer, which reduces the distribution voltage to the low voltage "utilization voltage", "supply voltage" or "mains voltage" used by lighting and interior wiring systems.