transformer used in reverse

[electrofelon]

A client has a 3 phase transformer intended to be a 240 delta primary to 120/208Y secondary. It is being used backwards to supply some 240 three phase loads from the 120/208 service. It is installed with the three supply phases along with a neutral connected to XO which is also jumpered to the case. I think I should remove the neutral and unbond the XO from the case yes?

 

[iwire]

XO should be left unconnected and one phase should be bonded or you need ground fault indicators.

 

[electrofelon]

XO should be left unconnected and one phase should be bonded or you need ground fault indicators.

Unconnected from both the neutral and from the case correct? Secondary is currently ungrounded and does not have ground detectors, I am aware it is not compliant. It is a very old installation and I will propose they remove it. My current work there does not involve this transformer, I just happened to notice it and peaked inside.

 

[ActionDave]

Unconnected from both the neutral and from the case correct? ......

Correct.