Question:
Can frequency inverters (230 V-devices) be operated on the IT mains (1* 230 V, 3*230 V) with earthed outer conductor?
Answer:
Yes. In case of 2-poles supply (L1, N) via TN mains the PEN conductor has also PE potential (earthed neutral). Consequently, in case of an IT mains with earthed outer conductor there will be identical voltage ratios between L1 (L2, L3) - N - PE, just as in case of a TN mains with earthed neutral.
Search term: Isolated, insulated, network forms
