Mike wrote:
I am attaching some smoke and heat detectors to ceiling boxes. The
boxes are connected by 12-3 where the red wire is for the interconnect
between alarms. The 12-3 is fed off of a standard bedroom circuit.

The 12-3 also has a ground wire, of course. However, the ceiling
boxes for the alarms are plastic. And, the alarms do not have screws
to attach ground wires.

Where should I put the ground in each plastic box? I will pigtail
feed-in and feed-out grounds in each box. Should I do more than this?
And what about the ground in the final alarm box, where there is only
a feed-in wire? Should I just wirenut the ground and let it sit in
the plastic box?

thanks,

mh

Note: the following is a guess ...

Do the alarms have metal ears used to secure them to the box? How about
putting a ground wire under one of those ears or under the screw securing
it?

--
Joseph Meehan

Dia duit