We have been contracted to install some equipment, in a large room, at a customers site. The facility power entering the room is 208VAC 3-phase wye power with both a neutral conductor and a ground conductor. The equipment requires 480VAC 3-phase wye power. Therefore we intend to use a delta-wye 208:480 75KVA transformer.
My questions are:
1) Would the 480VAC power be considered a separately derived system?
2) Can or should the facility neutral conductor be connected to the transformer secondary neutral (X0 terminal)?
3) Can the facility ground wire be used as the GEC to ground the secondary neutral (X0 terminal), provided it is sized properly for both the primary and secondary currents, or does it have to be a local ground such as building steel or a water pipe?
4) Can or should you connect both the facility neutral conductor and a GEC wire to the transformer secondary X0 terminal?
Thanks
My questions are:
1) Would the 480VAC power be considered a separately derived system?
2) Can or should the facility neutral conductor be connected to the transformer secondary neutral (X0 terminal)?
3) Can the facility ground wire be used as the GEC to ground the secondary neutral (X0 terminal), provided it is sized properly for both the primary and secondary currents, or does it have to be a local ground such as building steel or a water pipe?
4) Can or should you connect both the facility neutral conductor and a GEC wire to the transformer secondary X0 terminal?
Thanks