6.A. How many grounded neutral conductors are in a 208Y/120 volt, 3-phase, 4-wire system? A. Three B. Two C. Four D. One 6.B. A separate building that's supplied with a feeder or branch service will also need a A. separate EGC from the supply EGC. B. transformer for isolation. C. neutral conductor bonded to ground. D. grounding electrode system.

5.a. The aging of transformer insulationA. increases as the temperature increases.B. does not affect the transformer life.C. is not affected by the temperature.D. decreases as the temperature increases.5.b. Excessive power-transformer noise at the start of operation is most likely caused byA. an open feeder switch.B. a loose brace.C. a defective radiator.D. an open load fuse.

A 220-kVA transformer with .2% resistance and 4% reactance and another  120-kVA transformer with 3% reactance and .15% resistance with the same  voltage ratio. the phase angle is 33 degree and the total load .25 MVA. How much the load of each transformer.  what are the load currents of each transformer  if a1 =20 and a2=25?

A three-phase transformer bank has the primary and secondary windings connected in a wye configuration. The secondary center tap is being used as a neutral to supply single-phase loads. Will connecting the center-tap connection of the secondary to the center-tap connection of the primary permit the secondary voltage to stay in balance when a single-phase load is added to the secondary.   Referring to the previous transformer connection. If the center tap of the primary is connected to a neutral conductor on the incoming power, will it permit the secondary voltages to be balanced when single-phase loads are added??...