# 480v delta/400v wye with Neutral ungrounded

I have a European machine using a 480/400 volt three phase transformer. The neutral conductor is used to power some devices at 230 volt. The manuf. insists that the neutral must not be solidly grounded. I believe this creates an unstable electrical environment for the machine electronics also, it creates a shock hazard under ground fault conditions. Am I thinking correctly on this?