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The previous homeowner did some electrical work to upgrade the dryer outlet to a 4-prong receptacle along with new 10-3 wiring. It was all brand new and looked copacetic.

I'm thinking of moving the dryer receptacle, so I traced the wire from the outlet back to the panel. I noticed a J-box along the way where the new cable converts from a 10-3, with ground, to a 10-3, without ground (Without ground must have been the original house wiring). The ground of the new cable was tied to the grounding post of the metal J-box, but nothing was grounding the box. The two hots and neutral are just tied and capped, but nothing is tied to the ground wire going to the dryer.

Essentially it is completely ignoring the ground. Should I bond the neutrals to the grounding wire? Should I continue to ignore the ground?

I know what you are all going to say... I should run a brand new 10-3 all the way back to the panel... but that stuff is EXPENSIVE.

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    I believe that you're allowed to just run a new ground form the J-box back to the panel, since you're allowed to retro-fit ground to previously ungrounded outlets that way... – brhans Feb 4 at 23:23
  • @brhans that sounds like an answer. – Jim Stewart Feb 4 at 23:26
  • "10-2" would have only two insulated conductors. The original wiring for dryers was 10-3 (without gnd) and the new wiring should be 10-3 + ground. – Jim Stewart Feb 4 at 23:31
  • Can you get a single 10AWG wire back to the panel by some route or another? – ThreePhaseEel Feb 4 at 23:36
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    @JimStewart. You are right. They are both 10-3. One with ground, one without. I might be able to get a separate ground back to the panel. – Chris Feb 5 at 0:36
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What a fiasco. That was very bad work.

Unless the ungrounded 10/3 is running inside steel conduit all the way back to the panel, in which case the steel conduit is the ground, and the work is complete. However running cable inside conduit is the work of a dullard.

The good news is it sounds like the ungrounded 10-3 is quite old work, making it grandfathered. As such, you are allowed to retrofit a ground wire. It must be 10 AWG, can follow any practical route, and must go back to either

  • the panel the circuit is powered out of,
  • a junction box served by another circuit served by that panel whih has a #10 or larger ground wire back to the panel, or
  • somewhere along the Grounding Electrode System: the bare wires from the panel to the ground rods/water pipe.
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    Thanks Harper, so to your second bullet, I could jumper a ground wire over to the junction box that used to feed the electric stove. The stove was removed and replaced with gas, so the feed wires aren't even used. – Chris Feb 5 at 1:59
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Don't ignore the Ground. Do look a bit closer. Some old BX cable had a flat metal strip as the Ground instead of the normal looking bare copper conductor we see today. I have seen many applications with this old cable where common practice was to fold the flat Ground strip back at the box connector and wind it around the outside of the BX, then clamp it down with the box connector clamp. Done this way it wouldn't be easy for you to spot from inside the box. Otherwise, as Harper already said, it could be fed by metal conduit, which doubles as the Ground conductor.

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