Good day

We are upgrading a 3phase installation for one of our local schools, the building was wired early 60's. A 3 phase, 4core 50mm swa cable comes into the kitchen without an earth wire?! The neutral - Earth reading is 1.78 volts and the earth wire tingles when you touch it! Everything was ripped out and the whole building rewired.
My question now is, do I need to have an earth wire connected to the building if the db passes all the tests?

I personally feel an earth wire is always a good thing to have, irrespective of the test results but my employer feels different about it..
Please advise

Greetings
Thys
Orania