Part VIII of Article 430 provides the requirements for motor control centers. Please note, this is distinct from requirements from motor control circuits (Part VI) or motor controllers (Part VII).
It cannot exceed the rating of the common power bus [430.94].
- You must connect multisection MCCs together with either an equipment grounding conductor or an equipment grounding bus [430.96].
- You must arrange the phases so they are A, B, C from front to back, top to bottom, or left to right, as viewed from the front of the MCC. Other busbar arrangements are permitted for additions to existing installations, but they must be marked [430.97(B). An exception is you can use C, B, A where connecting rear-mounted units to a vertical bus that is common to front-mounted units; ensure everything is properly identified.
- Use the minimum spacing table that is in Part VIII; it's Table 430.97(D).