3

I'm cleaning up some of my circuits. I have one circuit that, because of its location, would be a major project to run a ground wire (or a romex, to add ground).

I planned on putting a GFCI at the beginning of the branch to bring it to code, in lieu of the grounding wire.

However, I found that all of the branch down-stream from the first outlet has been retrofitted with romex and has a ground wire leading from each receptacle to the next.

So in other words, there is a ground wire connecting each receptacle to one another, but no grounding path back to the main panel

Given that there is no grounding path in the branch, should I still connect each down-stream grounding wire together? Or should I leave the grounds "capped" and in the receptacle boxes?

10
  • 1
    If there's a ground in the box, it should be connected to the box (if metal) and/or the device. Look into the rules in the 2014(?) NEC that allow for retrofitting a ground after the fact. You should be able to tie that ground wire into a ground somewhere else that then goes back to the panel and grounds these outlets properly.
    – FreeMan
    Sep 2 at 17:33
  • 3
    Would it be a major project to get a ground conductor from any point on that circuit to any other point that has a ground available? When retrofitting ground, the conductor doesn't have to follow the path of the hot and neutral back to the source panel.
    – Greg Hill
    Sep 2 at 18:12
  • 1
    What do you plan on plugging into the outlets? Stuff with plastic housing is okay, not too sure about metal housings and if non grounded GFCIs be good enough. Have read on here about "no equipment ground" warnings required.
    – crip659
    Sep 2 at 18:13
  • 1
    @GregHill I didn't know that. Yeah, I could feasibly run a ground wire to a different part of the circuit which isn't the start of the branch. Could I tie the ground into the ground of a nearby circuit?
    – Tyler M
    Sep 2 at 18:19
  • 1
    @crip659 kitchen appliances, so toaster, blender, etc... yeah, I'm pretty sure I have to label it "no equip. ground" on each outlet if I do a GFCI in lieu of ground wire
    – Tyler M
    Sep 2 at 18:20

1 Answer 1

6

First, try to run a proper ground.

I gather it's difficult to establish a route back to the panel, but you don't have to. In 2014, NEC greatly liberalized the "retrofit ground" rules (I'm editing for readability):

250.130(C) Grounding Receptacles or Extensions. The ground of a receptacle or circuit extension shall be permitted to be connected to any of the following:

(1) Any accessible point on the grounding electrode system (the "ground spike" that ties your panel's grounds to the actual dirt) as described in 250.50

(2) Any accessible point on the grounding electrode conductor (that thick bare copper wire going out to your house's grounding rods*)*.

(3) The ground bar within the panel or subpanel where the branch circuit for the receptacle or branch circuit originates

(4) A ground wire that is part of another branch circuit that comes from the same panel or subpanel as this circuit

(5) (inapplicable)

(6) The ground bar on your MAIN panel (not subpanel)

Added in 2014 was #4, allowing running the ground wire to any other circuit that is also grounded to the same panel. That's a big winner.

And #1-2 are saying if you can access the Ground rods or the bare wire between panel and ground rod, that'll also do. (you must not cut this wire; you tack onto it with a "split bolt".

And #4-6 are saying that if this circuit is fed out of a subpanel, you can go back to either that subpanel or the main panel.

An "island of grounds" only spreads the danger.

I realize the temptation is to say "What else can I do?" but actually connecting grounds together when nothing connects to real ground, simply expands hazards rather than eliminate them.

Say you have 12 boxes all connected by the ground wire to each other, but not back to the panel. One of them has a bolted hot-ground fault because the ground wire touches the hot wire when you're pushing a switch back into the box. It wants to flow 200 amps to ground which would result in instant breaker trip. But it can't, because ground doesn't go back to the panel. What is happening instead?

Instead, the ground is yanked up to 120V voltage. Because it's physically attached to the hot wire by the bolted fault.

And since this ground is connected to other grounds in the island, this yanks all those other grounds up to 120V also. Switch plate cover screws are now at 120V. Anything with a metal chassis is now at 120V. Everything you assumed was safe is now dangerous. So congratulations - by creating an island of grounds, you just distributed death.

It would be a much graver sin if the receptacles in that island of grounds were changed to 3-prong receptacles. Because now it doesn't even take a wiring fault, a fault in an appliance would suffice.

In metal boxes, ground to the metal box first!

On the high hopes you are able to get the grounds home one way or the other, let's talk briefly about grounding where metal boxes are involved.

When the box is metal, the ground wires from cables need to go the metal box first. It is the highest priority to be grounded. I mention that because plastic people tend to "go with what they know" and attach the ground wires to the outlet/device only. Actually with metal boxes it's the other way 'round - you ground to the box, and then often you are finished - many devices don't need a ground wire even run to them.

  • Switches don't need a ground wire. They pick up ground from the box via the mounting screws.
  • Receptacles do the same trick if they are labeled "Self-Grounding". Any of the better $3 receptacles will do this.
  • If its metal yoke bottoms out on the flange of the metal box, and the screw is run all the way down, and it's hard clean metal contact, that covers grounding. (so not covered in paint or rust, and not floating on drywall ears - for that use "self-grounding" types).
5
  • Thanks @Harper. Can I ground against a nearby sink pipe (it originates from the dirt)? It's galvanized steel - not sure if that's an approved material?
    – Tyler M
    Sep 2 at 19:10
  • @TylerM -- you're trying to get back to the panel, or to the wires that connect the panel to the ground rods/piping, not to "ground" Sep 3 at 2:12
  • going to dirt does not help you @TylerM, it has to go back to the panel ultimately. Water pipes are not a valid choice, but if you have access to the water pipes just follow them. Sep 3 at 5:47
  • @Harper-ReinstateMonica If I can't ground to the water pipe, in what use case would I use one of those grounding clamps for water pipes?
    – Tyler M
    Sep 6 at 14:00
  • @TylerM those grounding clamps were never for grounding random branch circuits to water pipes, which has always been illegal. The sole use is when using a water pipe as the system Grounding Electrode Conductor. Just because HD/Lowes sells a thing does not make it legal to use for any darn use. For instance they sell NEMA 10-30 sockets that are entirely illegal except to replace broken ones in-kind. 99.5% of sales are NOT to replace broken ones lol. Sep 6 at 22:55

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.