1) Thanks for the replies Jason
2) A yellow conductor with green stripes is also a grounding conductor and that will get spliced to the green wire. You will need a short piece of either green or bare copper wire to make a pigtail connection using a plastic wire nut. Only 1 wire gets terminated onto a screw and not 2 wires. Thus the reason for the pigtail or the 3rd short piece of grounding wire.
3) If your box is metal, you may either have metal conduit or Romex cable or BX type of Armored cable originating from the main electrical panel. Take a look on top of the panel and you should be able to determine the type of wiring scheme that was used.
4) If you have metal conduit going back to the electrical panel, then the metal conduit is acting as the ground. Same if BX Armored cable type was used. If either of these, you can either connect the short pigtail directly to the green ground screw on the mounting bracket or you can connect the pigtailed short piece of ground wire directly to the back of the metal box using a green ground screw.
5) If you have Romex type of cable that fed for the house wires, you should have a bare copper wire screwed onto the back of the metal box. The bare copper wire grounds the metal box. If you have this arrangement, then just ground the pigtail piece to the install bracket green grounding screw.
Hope this helps.........If you have any additional questions, let me know and I'll be glad to answer them for you.
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