Correcting Open Ground - Switched Disposal/Dishwasher Receptacle - Picture Included

buckybadger

I was using my outlet tester around the house and came across an open ground in the outlet under the kitchen sink for the dishwasher/disposal. The top half of the receptacle is controlled by the switch for the disposal.

The only missing link in the ground path is a direct splice between the switch and receptacle although the switch and receptacle are grounded to the two respective boxes, which are connected by metal flex conduit. I know on paper the switch and receptacle should be directly connected, but shouldn't the way this is set up be providing a grounding path? Since my tester reads open ground my inclination is to just run a grounding wire between the two wire nuts (picture).

Here's a picture to make things clearer.
www.patrickdaley.com/sink.png

plummen

if the boxes are not mechanically grounded through conduit all the way back to the panel,or if the piece of romex sleeved through the flex is not bonded to the metal boxes with a ground screw you will have no ground through the boxes.

buckybadger

In both of the metal boxes the ground from the romex is connected to a ground screw.

plummen

is it bonded in the service panel?

buckybadger

I can't say with absolute certainty, but there is a metal j-box in the ceiling of the basement just upstream from this with a receptacle that does test as being grounded.

plummen

go from the hot side of plug under sink to the ground wire with your meter,that will tell you if its grounded back to panel or not.

buckybadger

I'll check that when I get home.

Could my tester be showing "open ground" because the switch and receptacle don't have their grounds directly spliced together?