My house initially had many outlets grounded to the copper plumbing using ground pipe clamps like this one which I know are no longer allowed via code:

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I have gone through and replaced my copper lines with PEX for finishing a basement. In the process I had an electrician install a new breaker box. The breaker box itself has a copper line that runs from it to my water supply source (copper line).


To avoid having to run new 14/3 wire for all outlets, is it acceptable to attach my outlet grounds to the circuit breaker ground wire using a split bolt connector like the one shown below? If it is acceptable, is there any guideline to how many per terminal are allowed?

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  • Believe it or not those split bolt connections violate code because they are not in a box. Most split bolts are for 2 wires but some are listed for more but to be totally legal they need to be in a box. I don’t know who told you pipe was not legal but the NEC still allows it in the 2020 code 250.52.a.1, and for those that need photos exhibit 250.31. Just because code is updated never requires a change, knob and tube wiring with Edison fuses is still 100% code legal for the homes it was installed in. If you choose to update the updates need to meet code.
    – Ed Beal
    Nov 18, 2020 at 17:25
  • @EdBeal Why is a box required? Nov 18, 2020 at 17:58
  • All splices are required to be in a box, yes even a ground the only time not required is for the pipe / rebar type clamps. I got hit on this long ago non reversible compression crimps needed for grounding I thought it was nuts but complied.
    – Ed Beal
    Nov 18, 2020 at 19:40
  • @EdBeal Can you also ground to flexible gas lines (CSST) still? like these homedepot.com/p/… The manufacturer itself says it is fine, you just take yellow jacket off for a section then use grounding pipe clamp. Is that legit still?
    – Eric F
    Nov 18, 2020 at 19:54
  • 1
    It is not a grounding electrode but the metal is attached to the grounding electrode system , all metal likely to become energized..,the clamp style for pipe and rebar do not require a box.
    – Ed Beal
    Nov 18, 2020 at 19:58

3 Answers 3


NEC 250.130(C)(2) Allows connection of ground for replacement receptacles to "Any accessible point on the grounding electrode conductor".

How many wires per connector and size would be subject to the NRTL Listing of the device you are using, which includes the instructions with the device. It seems the smallest wire permitted by the device you show may be larger than the wire you are using.

  • Yup, the package plainly states an allowable wire size range, and the wires used are afoul of that range. A different product should do the trick :) Nov 19, 2020 at 1:04

Actually, you're in luck.

In 2014, they changed NEC to greatly liberalize the rules for retrofitting grounds to ungrounded outlets (of any kind). Before, retrofits were allowed for a few particular places... now they're allowed everywhere.

You can run just a ground wire. (which you normally can't do). It doesn't need to follow the route of the original cable. It needs to be big enough: #14 for 15A breaker. #12 for 20A breaker. #10 for 25-60A breaker. And you can terminate it any of these places:

  • The service panel (obviously)
  • Any junction box that has a ground wire going back to the panel, if the ground is big enough. It can be on a different circuit, that's fine.
  • Any junction box that has (non-flexible) metal conduit back to the service panel. Flexible armored conduit/cable is hit-or-miss whether it is a legal ground wire.
  • Any point along the grounding electrode system wires - that is those bare copper wires running between panel and grounding rods/water main/Ufer ground.

You cannot take it to a water pipe, for reasons which should be obvious :)


Right idea, wrong connector

Tapping retrofit equipment grounding conductors (circuit/outlet ground wires) off the grounding electrode conductor (panel ground wire) is permitted by NEC 250.130(C) point 2; however, you can't break the equipment grounding conductor to do so, and more importantly, you need to use the correct connectors for the sizes of wire installed. This is where your plans so far fall short: your split bolt is rated for 8AWG thru 4AWG wires, with no indication of separate tap ratings for an application where smaller conductors are tapped off, such as yours.

As a result, I'd switch out those connectors for ones more suited for your application; my preference would be something like an Ilsco GTT-2-2, but any connector that a) takes the correct wire sizes for both run and tap and b) can be assembled around the existing grounding electrode conductor without breaking it will work. (Note: while putting these junctions in a box could be treated as a Code requirement, it practically can't be as you'd then have to cut and compression splice the GEC in order to retrofit equipment grounding conductors, something I doubt the authors of NEC 250.130(C) intended. Also see NEC 250.10 re: protection of grounding splices from physical damage -- Ilsco makes covers for the GTT series connectors, if that helps.)

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