XFMR Bonding

[Brandon Loyd]

I found a 3 phase 480/208Y120 XFMR installed just for one large machine. They aren't using a neutral for the machine. There are no wires on the XO. Secondary voltage is 229,227,226 phase to phase, and 110,129,156 phase to ground. Even though they are not using a nuetral, is it required by code to bond the XO? Will not bonding it cause future problems with this XFMR?

 

[david luchini]

Yes, this separately derived system is required to be grounded per 250.20(B)(1).

 

[Brandon Loyd]

Will this condition cause damage to the XFMR or to the machine that is connected to it?