I am putting together a concept for a project. I don’t see a problem with it but it wouldn’t hurt for other opinions. I am away from the office so I don’t have my resources to check things out (what a way to spend a vacation).
We have a large warehouse that we are planning to convert from 480 delta to 208 wye. There is no 480 loads in the building and there are about a half dozen 30 year old transformers we are paying impedance losses on for no reason. The site use to be on diesel generation.
To minimize impact on the occupants, my concept is:
• Install new MDP next to the old MDP as put of a local utility upgrade.
• From old MDP, feed a temporary transformer that will power the new MDP.
• All new feeders will be piped from new MDP to close as practical to existing panels
• When schedules allow like on weekends, one transformer at a time:
* One transformer at a time will be taken out of service
* Old feeder will be removed.
* New panel replacement as needed.
* New feeder to panel will be finished piping and pulled, then energized
• Demo out remaining of old feeder, set up for next change over during the week
• Once all the old circuits are out of the old MDP, do a service swap and the POCO will retap their tranny for 208.
• Old service will be will be demoed out.
Last edited by sparkyinak; 09/18/11 12:47 PM.