I just bought a house, and my new washer/dryer is being delivered tomorrow. I have the older style 3-prong 240V outlet, which I know I'm allowed to still use. I also have a 2-prong 120V outlet next to it for the washer, which I don't think I can use. Since I have to upgrade the 120V outlet, I was going to just do both at the same time.

The outlets are located at the exact opposite diagonal corner of my house as the main panel. I had planned to just pull out the old ungrounded 10/3 and 12/3 and replace it foot by foot back to the breaker panel, ground it, and call it a day - but then I noticed that my breaker panel's main ground runs all the way back to the laundry room, and connects to my main water line which just happens to be next to the washer.

My question, would it be safe, and code, to just run a #10 ground wire over to the same ground clamp on the water line? Or maybe secure a secondary ground bus near the water line, to tie into?

I know the codes need to cover every possible application, but it just seems silly to run $200 worth of new grounded cable back to my breaker panel, to tie into a ground that literally runs all the way back to where I started.


2 Answers 2


Edit: you can tap the Grounding Electrode Conductor aka GEC, which is the bare grounding strap going from the panel to the water pipe. NEC 250.130(C). You cannot use the water pipe itself, though.

Or… You can retrofit just a ground wire back to the panel.

They broadly liberalized the rules for this in 2014 to allow this for almost any circuit -- but they had already liberalized the rules for dryer circuits some time prior. In fact, since the washer and dryer plugs both come out of the same service panel, they can share the ground wire.

Grounds don't need to be insulated (must be green or green/yellow if they are) and they don't need to follow the same route as the wiring they are grounding. They do have to be installed using proper wiring methods. Grounds must be large enough for the circuit they are protecting.

All the circuits out of that panel can share the ground, so it helps to run a "backbone" to the big appliances in #10 or #8, then tie everything else to that in reverse order of size. Splices are allowed in ground wiring, just do it legally in in junction boxes (which means pre-planning where those junction boxes would be useful when laying the backbone.)

  • Let me get this straight: Connections to the heavy "backbone" ground wire must be in a junction box? If one wants to retrofit a ground from an old style 3-wire dryer plug and join it to the existing backbone ground, how is that brought into a box? Are there special ("clam shell") boxes which allow the backbone to pass through the box and have the added ground clipped onto the backbone? Commented Jan 23, 2018 at 14:49
  • So for instance you would place junction boxes where you expected to have junctions, and run the backbone ground from box to box, leaving 6-9” inside the box so you can wire-nut it, just like you would with any other circuit, cable clamps on the box entry, etc. Same treatment you'd give Romex. Commented Jan 23, 2018 at 17:31
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    So one has to cut the heavy backbone ground to get it inside a box, and probably means two boxes due to lack of slack? Upon reflection on your comment I now see that if the connection were loose it could arc (hence the requirement of enclosure in a box) but I could imagine a special box that would allow the heavy ground to be laid in without cutting and the retrofitted ground clamped on. So it is not done that way? Commented Jan 23, 2018 at 19:11
  • I was really asking about what could be done correctly, but expediently in a retrofit of a ground. Commented Jan 23, 2018 at 19:24
  • If you can find a place in Code that authorizes an inline splice of a ground wire, then OK. Inline splicing is common in K&T so maybe it's allowed. But absent a cite I am disinclined to assume it is legal. Therefore my advice is at initial installation, site junction boxes at appropriate intervals or locations where you expect to want to tie in future grounds. Commented Jan 23, 2018 at 19:39

Here's what I ended up doing. I wanted to bridge around my water meter anyway, so I clamped some #8 on both sides if the meter and ran that up and over to a handy box. I pulled a little out, cut&spliced it (for later tie-in) and continued the run over to my new grounded dryer plug.

Bonded Ground to water main

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