L1 & L2 both to ground would be a 'ground fault'
Still might not be detected...
a human holding both L1 & L2 ... would be a 'short'
If my twin brother who has the same impedence as I were holding L1 while I held L2 standing on the ground in bare feet...
"The GFCI will not protect a person against a line to line shock"
makes the noodle look important !
A GFCI won't protect against line to neutral either (120 or 240 V). What the listing doesn't mention is that it may also fail to detect symmetrical (240 V) line to ground faults.
A 120 V GFCI still may trip when a human hand shorts line to neutral while standing on the basement floor, touching the sink, etc.
