higher power
Member
- Location
- plainview, tx. usa
does the neutral of a separately derived system ( such as from a dry transformer ) have to be isolated from the neutral of the power coming into the building 480y/277.
separately derived systems
- Thread starter higher power
- Start date
- Status
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
You need to isolate current carrying portions of each system from each other meaning you can not have a common neutral conductor that carries both 120 and 277 volt neutral current. However they are both grounded conductors and will have a bonding connection between them because they are both grounded. Equipment grounding conductors are also part of this bonding and you would only need one EGC in raceways or cables that contained conductors of both systems.
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