phase to phase wiring question

[Simon47]

If you don't get 230v to earth on all phases then you have a problem. That's simple my friend. (assuming no unconventional wiring in place).

For the benefit of anyone coming across this thread later ...
As others have commented, this is not true in the general case. It is the case in the UK and many other countries, but having 4 wire systems with an earthed neutral point is not universal. And it's clear the question is not about a UK supply.