In this article:

1. 3 Phase, 1-Phase of electrical distribution system.

2. Delta or Wye

3. Wild leg, High Leg, Split Phase

4. Kinds of voltage

5. Applicable voltage & connection for SolaX inverter

1. Wye connection

1.1 American system

The most common commercial building electric service in North America is 120/208V wye, which is used to power 120V plug loads, lighting, and smaller HVAC systems. In larger facilities the voltage is 277/480V and used to power single phase 277 volt lighting and larger HVAC loads. In western Canada 347/600V is common.

3-Phase, 4-Wire 600Y/347 V is similar with above two systems and just the L-L voltage is 600Vac and L-N is 347Vac.

1.2 EU system

3-Phase, 4-Wire 380Y/220V, 400Y/230V, 415Y/240V is the most common LV distribution system in EU system. 415/240V is for UK.

2. Delta connection

2.1 American system

Used primarily in industrial facilities to provide power for three-phase motor loads, and in utility power distribution applications. Nominal service voltages of 240, 400, 480, 600, and higher are typical.

Similar to the 3-Phase, 3-Wire Delta discussed above, the below Wild Leg or high Leg add a center-tap on one of the transformer winding to create neutral for 120 volt single-phase loads.

240/415/480V Wild Leg is same as 120/208/240V Wild Leg except double the voltage.

Note: Wild Leg i.e. High Leg Delta was Phase B before NEC2008 releasing. Now the Led should in Orange Color and Phase “C” in site electrical wiring.

One phase grounded delta connection.

3. Single phase

Another system also known as Edison system, split phase or center-tapped neutral is the most common residential service in NA. It’s actually identical to the center-tapped phase of Wild Leg system.

Japan has the 100/200V split phase system