Wiring diagram for three phase power with two 200 amp service boxes inside building
This work requires a license (or qualified person) everywhere that the National Electrical Code is enforced.
If you're asking how to wire a single phase 200 amp panel from a larger, 3 phase panel of the same voltage - ONE way is to install a 2 pole - 200 amp breaker into the 3 phase panel. Provide 4 correctly sized conductors with the correct insulation in a cable or conduit between the 3 phase panel and the 200 amp single phase panel. Two of these conductors should be black and red (for 120/208 volt system) and connect to the 2 pole - 200 amp circuit breaker terminals, the third should be white and connected to the neutral bus bar. The forth should be green and is connected to the neutral bus bar as well but *only if* it is "service equipment" If it is a "main or sub panel", the green wire should be connected to the ground bus bar. The other end of the conductors should be terminated in a "main lug only" 200 amp panel. The back and red connect to "line 1" and "line 2" bus lugs, the white to the neutral bus bar that is NOT electrically connected to the panel enclosure (do not install the screw or strap between the bar and enclosure). The green must be connected by installing a separate bar that is securely fastened both mechanically and electrically to the enclosure for ground connections.
There is a great deal going on here - and plenty of variables that can change how to do this work, safely and correctly. This is an example of just ONE of many different ways to do the work for a particular installation. There is no one way that works for all situations. If your situation does not support this method - you will have an unsafe installation and subject the building and people in it to a dangerous fire / safety hazard.
Please, consult a licensed electrician before attempting this work.
Nov 17, 2011 |
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