I will answer this with...MATH...the universal language! (You didn't specify which model, so I will use WHITE)
Thermaltake SMART 700W 80+ WHITE with NEMA-C13 grounded three-prong connector.
700W ÷ 115V = 6.087A but @80% efficiency = 7.609A and NO ACTIVE PFC (0.56) = 13.587A MAX (Yikes!)
700W ÷ 230V = 3.043A but @80% efficiency = 3.804A and NO ACTIVE PFC (0.56) = 6.793A MAX
So, in this case, a 230V 6A cable would MORE that suffice, because I would highly doubt that you will be operating that, particular PSU @50% (350W), and wouldn't recommend anything above 65% (450W)!
If it is a 80+ DPS-G (Bronze) unit, or better, with PFC, then current draw will drop significantly!
EDIT : OOPS! Wrong standard! Yours will be IEC-C13 or similar (same connector, EU standard)