GE 15070 timer does not have ground wire.
I assume this timer is double insulated, just like some power tools and electronics only have two prong plug.
Leave bare ground wire attached to other bare grounds in the box, and shove grounds to back of box.
I have one of these timers installed.
Timer has red, black and white wireshttp://waterheatertimer.org/GE-timers-and-manuals.html#15070
How to wire GE 15070 timer:
1) Switch has 2 insulated wires. Take switch wires and connect them to
timer-red-wire. Choose either one for now.
In back of electric box are white wires twisted together and covered
with wire nut. Connect timer-white to these wires.
3) If electric box does not have white wires described above, then
connect timer-white to bare ground, along with timer-green wire.
Turn on electricity, and slide switch to ON-or-OFF. If lights come on, timer
is wired correctly. If lights do not come on, then reverse timer-red
and timer-black wires.
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