In article , Goedjn wrote:

Think it is necessary, or a code requirement, to ground the lower box also ?

If you were running the cable straight through the box,
I'd have said "no, it's not worth grounding it.".

And you'd have been wrong.

Grounding of metal boxes is a near-absolute requirement of the NEC. There are
only a handful of exceptions, very narrowly defined, and this is not one of
them.

--
Regards,
Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?