ABB MS132 - North American Voltage Supply Networks and Load Types; North American Voltages; Three-Phase Network Configurations

MANUAL MOTOR STARTER GUIDE
APRIL 19 58/80
7.2 North American voltage supply networks and load types
Electrical networks in North America supply power to residential, commercial, and industrial structures. Depending
on the amount of power required for a given installation, various voltage configurations can be utilized.
7.2.1 North American voltages
North American commercial installations are typically supplied using either 120/240 V AC split (dual) or
208Y/12 0 V AC, 3-phase wye networks. Industrial installations within the U.S. commonly use 480Y/277 V AC, 3-phase
wye networks. For Canada, the network voltages are increased to 600Y/347 V AC. However, 3-phase delta networks,
which do not offer a line-to-neutral voltage, are also common, most often supplying either 240, 480 or 600 V AC.
Application
Network configuration
(excluding ground wire)
Nominal supply voltage
(line-to-line)
Nominal supply voltage
(line-to-neutral)
Commercial
2-phase, 3-wire 240 V AC 2-phase (split/dual) 120 V AC 1-phase
3-phase, 4-wire (wye)
208 V AC 3-phase
120 V AC 1-phase
Industrial and large commercial
in the United States
3-phase, 3-wire (delta)
240 V AC 3-phase
--
3-phase, 4-wire (wye)
480 V AC 3-phase
277 V AC 1-phase
3-phase, 3-wire (delta)
480 V AC 3-phase
--
Industrial and large commercial
in Canada
3-phase, 4-wire (wye)
600 V AC 3-phase
347 V AC 1-phase
3-phase, 3-wire (delta)
600 V AC 3-phase
--
Table 22: North American voltages
Manual motor starters are commonly applied in both industrial and commercial applications. To meet the require-
ments for North America, they are suitable for use on 1- and 3-phase networks with line-to-line voltages up to
600 V AC.
7.2.2 Three-phase network configurations
North American 3-phase supply networks differ based on the secondary winding of the upstream transformer. The
two most common secondary winding styles are wye, which includes three power legs and a neutral, and delta, which
includes only three power legs without a neutral connection. These networks can be either grounded or ungrounded.
Solidly grounded wye and ungrounded delta networks are most common in North America.
Most common
Delta
(ungrounded)
Wye Delta
(corner-grounded)
Delta
(center-grounded)
Solidly grounded networks
Figure 35: Three-phase network configurations.