NEC requirements for open-delta 3-phase service.

[Sabbah]

Hi all,

What are the NEC requirements for a 3-phase service where a 120/240 open delta transformer is being used? The site is mixed use (commercial and residential), with separate meters and panels. One service feeds the whole unit though.

Thanks!

 

[don_resqcapt19]

There are no special requirements other than the identification of the high leg and not using "slash" (120/240) rated breakers on the high leg.

 

[augie47]

Code cycles later than the '08 you show as applicable by profile require "high-leg" panels to be legibly marked accordingly. Not a bad idea although not required by your Code cycle.