We're working to provide a small subpanel in a building with no convenient 208Y120. I want to use a 7.5kVA trans-panel unit(panel with built-in transformer). This would be connected to 480 volts from an existing subpanel. I would use a 2-pole CB for single phase primary of trans-panel. There is no ground lug or bar at this panel, but there is a neutral- it feeds HVAC units and has plenty of capacity. I am looking for thoughts about grounding the secondary side(120/240). Would it be protected properly with a cabinet ground at the 480 subpanel? This is all metal pipe installation back to main distribution, with grounded service. So total info- 7.5kVA xfmr(62A@120, rated 16A@480) with a load of 2) 2200 VA UPS units for computers(120 V). What do u think?
edit: The neutral in the 480 volt panel is not bonded, there is potential to 480V cabinet, cabinet is grounded through raceway at distribution 60 ft below. The 480V neutral will not be used in the trans panel- there is a neutral tap on 7.5 kVa secondary. Also made mistake and put 5 kVA instead of 7.5kVA-brain gas- sorry.
[This message has been edited by chi spark (edited 04-05-2004).]
[This message has been edited by chi spark (edited 04-05-2004).]
[This message has been edited by chi spark (edited 04-06-2004).]
