480/240 single phase step down transformer

[Jacobr123455]

Installing a step down transformer for a temp service on a commercial job site, hooked everything up per diagram but when a load is applied a phase shows 47 volts and b phase goes to 208, without load I have 120 from each leg to neutral/ground and 240 phase to phase

Is this an open neutral?

 

[don_resqcapt19]

Did you install the system bonding jumper? Without that, measurements to ground have no meaning because you have an ungrounded system.

 

[LarryFine]

Welcome to the forum.

You need to bond the secondary neutral to your building's grounding electrode system just like the power co. does.

 

[winnie]

If you are measuring L-G and getting funny voltages under load, then the problem is the lack of ground bonding.

If you are measuring L-N and getting funny voltages under load, then the problem is an open neutral connection.