F. WYE – WYE: 4-Wire, 3-Phase Service
A B C N
H1 H2
H1 H2
H1 H2
X3
X1
X3
X1
X3
X1
Tank GND
Tank GND
Tank GND
X2
X2
X2
a b c n
Primary Wiring - WYE: With a WYE connected high-voltage side, the H1 terminal of each transformer is typically connected to a different phase of primary. The H2 terminals are connected together and must be solidly grounded. Secondary Wiring – WYE : Transformers banks with this secondary configuration are widespread and used to service both single-phase and three- phase loads. Common service voltages are 208Y/120V and 480Y/277V. Occasionally, 416Y/240V and 830Y/480V services will be seen and can be accommodated with this bank configuration. 120/240V transformers used for the 208Y/120V service must be “split” by opening the transformer top, splitting the winding leads and connecting them in parallel. Failure to split and parallel the transformer windings will result in halving the kVA rating of the transformer.
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