According to this site the radical is やね, whose name comes from the kanji for 8　(ハ) : http://www.saiga-jp.com/cgi-bin/dic.cgi?m=search&sc=0&f=0&j=

According to　学研監修漢字辞書 (a real dictionary) the radical is 人 (ひと）. 

I don't think you can get a definitive answer because there are several sets of radicals in existence, compiled for different dictionaries (see also note by Choko) but other users of this site can explain etymologies at great length, if that it what you seek.

Personally I used to find radicals quite useful to look characters up but I can live with 全　being both of these.