Published by the International Electrotechnical Commission (IEC), this standard replaced the older IEC 60439 series, introducing a more rigorous approach to verification and design verification.
There is no "Part 391." The correct search should be or IEC 61439-2 . iec 614391 standard pdf best
The standard clearly distinguishes between two key roles in the manufacturing process: Original Manufacturer: iec 614391 standard pdf best