Hi

I have a query on a three phase isolation transformer. The transformer has a Star configuration but the third phase(Blue) is strapped to earth at the transformer on the secondary side. This means that the earth is at 230V so between any phase and earth you have 415V as you are across two windings, between Phase 1 and 2 you have 415V.
Between the third phase and the general earth(e.g earthing point of a TN-S system you have 0V as expected.

Question is, is this acceptable, the installation is 43 years old and there has never been a problem. The third phase/rail is live and accessable to touch by anyone but as there is no potential to earth as it an isolation transformer there is no issue? or is there?

Any suggestions would be great,