GreenLight UPS learning guide

Understanding UPS Voltages

Start with three familiar power families. Then use voltage names, outlet shapes, wire counts, and voltage relationships to identify the right GreenLight voltage code.

How we count wires: every conductor counts—including ground. In SOOW cable, 12/3 means three total insulated conductors. Family shading is a learning aid; conductor colors have separate electrical meanings.

Low Voltage

Familiar household and standard outlet power

120
3-wire
AKA: 100V, 110V, 115V, 120V, household, standard outlet, North American household
NEMA 5-15R receptacle
NEMA 5-15R
NEMA 5-20R receptacle
NEMA 5-20R
NEMA L5-30R receptacle
NEMA L5-30R
L
N
G
Line + Neutral + Ground
Typical example: SOOW 12/3
L-L—
L-N100–120V
GreenLight codes
AJ

High Voltage

International, commercial, and dual-voltage single-phase power

230
3-wire
AKA: 220V, 230V, 240V international, European, overseas, IEC power, marine
Schuko Type F receptacle
Schuko Type F
UK Type G receptacle
UK Type G
Blue IEC 60309 receptacle
IEC 60309 Blue
L
N
G
Line + Neutral + Ground
International single-phase
L-L—
L-N220–240V
GreenLight codes
EI
200+
3-wire
AKA: 200V, 208V, 220V, 230V, 240V, US high voltage, commercial, line-to-line, L6
NEMA 6-20R receptacle
NEMA 6-20R
NEMA L6-30R receptacle
NEMA L6-30R
L
L
G
Line + Line + Ground
No neutral normally required
L-L200–240V
L-N—
GreenLight codes
GH8
120/240
4-wire
AKA: 120/208V, 120/240V, split phase, dual voltage, four-wire, dryer-style power, L14
NEMA L14-30R receptacle
NEMA L14-30R
NEMA 14-50R receptacle
NEMA 14-50R
L
L
N
G
Two Lines + Neutral + Ground
Neutral makes 120V available
L-L208/240V
L-N120V
GreenLight code
P

Three Phase

Commercial and industrial systems using three energized lines

208Y
5-wire
AKA: 208Y/120V, 120/208V three phase, 208 Wye, commercial three phase, L21
NEMA L21-20R receptacle
NEMA L21-20R
NEMA L21-30R receptacle
NEMA L21-30R
L
L
L
N
G
Three Lines + Neutral + Ground
Example: an L21-30 whip using SOOW 8/5
L-L208V
L-N120V
GreenLight code
3Y
480
5-wire
AKA: 480Y/277V, 277/480V, 480 Wye, industrial power, plant power, L22
NEMA L22-30R receptacle
NEMA L22-30R
L
L
L
N
G
Three Lines + Neutral + Ground
Main section covers 480Y/277V Wye
L-L480V
L-N277V
GreenLight codes
3G3Z
400
5-wire
AKA: 380V, 400V, 415V, 230/400V, international three phase, European three phase, IEC
Red five-pin IEC 60309 receptacle
IEC 60309 Red 5-pin
L
L
L
N
G
Three Lines + Neutral + Ground
International three-phase convention
L-L380–415V
L-N220–240V
GreenLight code
3I
L — Line

An energized conductor that supplies power.

N — Neutral

A current-carrying return path that also makes lower L-N voltages available.

G — Ground

A safety conductor. It counts as a wire but does not normally carry operating current.

L-L / L-N

Voltage measured line-to-line or line-to-neutral.