On Mar 29, 7:56*am, "JoeSpareBedroom"
wrote:
Ya know those wind-up timers you sometimes (or used to) see in hotel
bathrooms for the heat lamps? I need to mount one of those, and an outlet in
a metal box. It'll be used for a portable electric heater which we regularly
forget to turn off. For grounding purposes, should the green from the
outlet, timer and cord all be attached to the box itself?


Is this a regular 4" square metal box you are considering using ?

I have made extension cords using these before but you have
to be careful where they will be used (normal 4" square metal
boxes are full of holes which will let any water or liquid spilled
near it into the box AND the knock-outs can become damaged
and push inward contacting live electrical parts inside) as
water and physical/mechanical damage can be a problem...

Find a water tight rated box... Those boxes have MUCH
fewer holes in them and use threaded knock-outs so they
are more durable...

Wrap all devices with several layers of electrical tape after
making up the connections... IF anything got damaged or
loosened it is better to have metal touching electrical tape
and hear it rattle around inside the box than have metal on
metal contact and blow a breaker...

~~ Evan