Could this voltage be something that is mentioned in following Schneider pdf,, page 22.??
http://www.electrical-installation.org/w/images/7/73/EIG_chap_L-2010_haute_def.pdf
(somewhere like in the middle of the page, related to 7-8% increase of fundamental 400V)
Thanks again,, and sorry for multiply posting ;)..
Regards,, Alen..