NEMA used to (and may still) allow something like a half a MA on the ground without considering it objectionable.
This is plenty to power most CMOS devices.
That was how it got started but IAEA seemed to be more concerned with load powered devices that put current through the load at a very low level, when the device was considered to be "off".
I think the title of the article was something like "Is it really off". That was the first time I heard the push for requiring a neutral everywhere.
