1

If I understand correctly, plug-on neutral panelboards allow GFI/AFI breakers to be installed without running a separate neutral wire (pigtails) from the breaker to the neutral bus bar, and they have the neutral wire from a branch circuit's load cable also attached to either the breaker or part of the panelboard in the immediate vicinity of that same breaker for the branch circuit, which also means non GFI/AFI breakers do not need a neutral wire routed to a dedicated neutral bar either, but the ground wire from the cable would still need to be routed to the neutral bus on a main service panel, or the ground bus on a sub-panel on all of the plug-on neutral panelboards I have seen regardless of the type of breaker or whether or not it is plug-on neutral.

Why do the manufacturers of these panelboards not do the same thing with the ground connection? Couldn't the breaker or its slot on the panelboard simply accommodate a third screw that could send the ground connection to a common bus without needing to route wiring to a dedicated bus bar location that is remote to the breaker in the box? Even in a subpanel, where the ground and neutrals need to be on separate buses, why not have things "under the hood" take care of the proper bus routing for neutral and ground? It would seem like it would be way more neat and less work to install.

I have not seen every panelboard that has ever been made, so I suppose it could exist and I just don't know.

Improve this question
6
  • 2
    Ground wires aren't routed to GFCI/AFCI breakers. Only power & neutrals. To have Plug-On-Ground breakers, the breakers would need an extra screw terminal and routing for a wire path that is not sensed. Extra complication and expense for an unneeded connection.
    – Triplefault
    Commented Jul 7, 2023 at 18:15
  • The benefit I'm seeing would be less wiring running around in different directions in the box. Is this the answer though? Basically, "it doesn't serve a function other than neatness so they don't do it"?
    – Ryan Mortensen
    Commented Jul 7, 2023 at 18:21
  • 4
    The entire point of the box is to permit wires to be run around. PON provides easy access to Neutral which GFCI/AFCI breakers require, without the pigtail that non-PON GFCI/AFCI breakers use for that. No breaker has any need for ground. If you want neat grounding, start running your wires in solid metal conduit where no ground wire is needed.
    – Ecnerwal
    Commented Jul 7, 2023 at 18:30
  • "less wiring running around in different directions in the box" The wires would still be running somewhere, either to the breaker or the bus bar. But the breaker manufactures would have to add the ground screw connection, meaning more money for the breaker. (Do non-GFCI/AFCI breakers have plug-on-neutral versions? I haven't seen them.)
    – Triplefault
    Commented Jul 7, 2023 at 21:06
  • 1
    Two, I suspect UL wouldn’t allow plug-on ground connections. Notice how although they still allow push-in “backstab” connections on receptacles and switches for hots and neutral, they require ground to be a screwed-down connection.
    – nobody
    Commented Jul 7, 2023 at 21:31

2 Answers 2

Reset to default
3

xFCI breakers require a connection from the breaker to the neutral bar. The plug-on neutral provides that connection.

xFCI breakers do not require a connection from the breaker to the ground bar. What would a plug-on ground do? Ground the breaker? Which part of the breaker would it ground? The hot? The plastic case? (Forgive the sarcasm but I think it's illustrative.) Or do you mean that the breaker should get involved in grounding, providing a path through the breaker for ground having no functional purpose other than to be symmetric to the other wires? I hope it's obvious that would be complicated, expensive, and dangerous?

I think what is driving this question has nothing to do with "plug on" but rather with the fact that with xFCI breakers, the hots and neutral from the branch circuit are both connected near the breaker so it would be symmetric and perhaps elegant (to some) if the ground was too. But the fact is, the hots and neutrals are not connected near the breaker, they are connected to the breaker. Again, the breaker has nothing to do with ground. So you are really asking why panels don't provide a pervasive distributed ground bar so that ground wires from branch circuits can be connected aesthetically similarly to the hot and neutral wires from branch circuits.

The answer is probably (I'm not a product manager for a breaker panel maker) A) because it would cost more and provide no benefit and B) because the terminal space around the breaker is pretty crowded, and it's actually easier on the installer if you don't crowd it even more.

It just makes no sense. The circuit hot and neutral are connected to the breaker, the breaker is connected to the distributed neutral bus. The circuit ground is connected directly to the ground bus, it does not have to be distributed because the breaker does not have to be connected to it.

Improve this answer
2

First, NEC 110.3(B) (follow instructions) and NEC 110.12 (neat and workmanlike) forbid running a panel with the cover off. NEC 110.2 also forbids homebrewing a custom panel cover that is transparent. Together, these foreclose on any aesthetics-based rationale relating to wiring in a panel interior. The purpose of panel wiring is safety; that's why we don't just get three ground bars and paint them black, red and white and nail them to adjacent floor joists and just attach wires there.

There is no safety win whatsoever in plug-on-ground, and a safety lose. The ground wire needs to be landed on a terminal in any case. Having that terminal be on a breaker with subsequent PoG, versus having it be on a bar, is not an improvement.

If you are overly concerned with wire clutter, note that there are several sites inside the panel box already drilled and tapped for the models of accessory ground bar listed on the panel labeling. Feel free to populate any or all of them to reduce needed ground wire length.

My standing advice of "make every hot and neutral long enough to reach any breaker space in the panel" does not apply to grounds.

Improve this answer

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

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