240V power is used in the US and parts of the world. In the US 120 / 240V 1 Phase 3 Wire is the standard for homes and 240V 3 Phase Open Delta is the standard for small buildings with large loads. In parts of the world 240V Single Phase 2 Wire is the standard for homes. Actual power company voltage varies (220v / 230v / 240v) by region, but to simplify we’re going to focus on 240V.
120 / 240V Single Phase 3 Wire (1P3W)
120/240V 1 Phase 3 Wire
In the US, 240V Power is provided to homes and small buildings as a 120/240V 1P3W power circuit. It provides 120V for light loads (lights, TV, etc.) and 240V for medium loads (Water Heaters, AC Compressors, etc.).
MAXIMUM POWER – In a single phase power circuit maximum power is calculated as the voltage times the current. If we assume it’s a 200A power circuit then the maximum deliverable power is 200 x 240 as follows
- Current (Amps): 200A
- Voltage (Volts): 240V
- Maximum Single Phase Power
- 48 KVA Kilovolt Amps or
- 48 KW Kilowatts
240V 3 Phase Open Delta (3P4W)
In the US, 240V Power is provided to small buildings with large loads as 240V 3 Phase Open Delta. It’s like 120 / 240V but also provides 240V 3 Phase for large loads (Machinery, etc.). It’s often called “Wild Leg” of “High Leg” Delta because one leg (Phase B) is different.
- THE GOOD – It’s inexpensive for the power company and it provides 120V / 240V Single Phase and 240V 3 Phase.
- THE BAD – The “Wild Leg” or “High Leg” (Phase B) can cause problems if you’re not aware it’s different.
- THE UGLY – The “Wild Leg” or “High Leg” (Phase B) is 208V to Neutral, so it’s different than the others.
240V 3 Phase 4 Wire Open Delta
MAXIMUM POWER – In an Open Delta configuration power circuit the maximum power is a little more complicated because you have to calculate single and three phase separately. If we assume it’s a 200A power circuit then the maximum deliverable power is 200 x 240 calculated as follows.
- Current (Amps): 200A
- Voltage Volts): 240V
- Maximum Single Phase Power
- 48 KVA Kilovolt Amps or
- 48 KW Kilowatts
- Maximum 3 Phase Power = 1 Phase Power x 1.732
- 83 KVA Kilovolt Amps or
- 83 KW Kilowatts
240V Single Phase 2 Wire
240V Single Phase 2 Wire
In some countries, 240V Power is provided to homes and small buildings as a 2 Wire 240V Single Phase power circuit.
MAXIMUM POWER – In a single phase power circuit maximum power is calculated as the voltage times the current. If we assume it’s a 200A power circuit then the maximum deliverable power is 200 x 240 as follows.
- Current (Amps): 200A
- Voltage (Volts): 240V
- Maximum Single Phase Power
- 48 KVA Kilovolt Amps or
- 48 KW Kilowatts
415Y / 240V 3 Phase 4 Wire (3P4W)
415/240V 3 Phase 4 Wire
In some countries, 240V Power is provided to buildings with large loads as a 415Y/240V 3P4W power circuit.
MAXIMUM POWER – In a Wye power circuit the maximum power is a little more complicated because you have to calculate single phase and three phase separately.If we assume it’s a 200A power circuit then the maximum power is calculated as follows.
- Current (Amps): 200A
- Voltage Volts): 240V
- Maximum 1 Phase Power per Phase = 200 x 240
- 48,000 Volt Amps (VA) per Phase or
- 48 Kilowatts (KW) per Phase.
- Maximum 3 Phase Power = 200 x 415 x 1.732
- 144 KVA Kilovolt Amps or
- 144 KW Kilowatts