What is the proper way to terminate unused electrical wires?

Question

I am replacing the wiring for a room and want to disconnect the old wiring. I came across: Terminating unused wire in breaker box

But, that is at the main panel. My primary question is:

#1 How to terminate unused wire at a junction box?

I was able to completely fish out the wiring for the lights and removed it entirely from the junction box, but the outlet wiring is not easily accessible. I do not want to disable the circuit at the main panel for this circuit since I am using it for the office and powder room lights.

#2 Should I cap both hot and neutral of the respective wires after disconnecting the line in to the outlet wire?

If I were ever to come across the wire in the future and I removed it from the junction box, even if it weren't connected, it would seem to be leading itself to a potential mistake or at the very least, require another junction box at that point in time (if for some reason I were to decide to use it in the future). Ideally, I would like to remove the wire, but it doesn't seem to be a feasible option.

I also have a 240v line that I asked an electrician to disconnect (used to operate a pump for a well). So that I know what to expect:

#3 Would he be pulling that wire out of the main panel, removing the breaker, installing a filler plate and calling it done? Or, would the wire need to stay in the main panel, but capped with twist nuts?

If he did the former, again, that would seem to lead itself to either a dangerous situation or confusion. That wire is only partly accessible without cutting drywall.

Another question that came to mind is:

#4 Since those wires are no longer connected, do they still need to remain accessible or can they be buried or covered?

Answer 1

View here from an owner of an old house with 5 generations of cable in the walls. I'm not an electrician. Some of this is driven not by Code, which does not govern wires that are entirely disconnected, but by my experience in maintaining and upgrading my home.

Cap and leave

In general: Cap and label unused wires, hot and neutral, in junction boxes and in the breaker panel. Leave the grounds connected. Do not remove them from boxes or the panel.

Labeling disused wires

• Label each end with the location of the other end.
• In the breaker panel, if you have a breaker that seems to do nothing and you don't know where the other end of its wire is, you can disconnect and cap its wires, but label them accordingly. "Formerly breaker 23, 15A, no known function".
• In any other junction box, if you know what breaker serves the wire, label it accordingly. If no breaker serves the wire and it's just dead, label it accordingly.

To emphasize "do not remove the ends from boxes":

• If the wire is up to latest code and is properly capped at both ends in a box, do not remove it. You may want it again one day.
• If the wire disappears into a wall or ceiling, and you cannot access or at least visually inspect every inch of it, do not remove its ends from boxes. The fear is that there may be hidden junctions in the walls, without junction boxes, that may reinstate power to these wires in unknown ways. It's unlikely but you don't know what you can't see. So leave the ends in the junction boxes, properly terminated.

Of course, you'd like to remove disused, unusable old wires from your walls. So:

Exceptions:

1. Remove any segment of cable (a single uninterrupted piece) from the boxes at its two ends if you can remove it entirely from the walls. That means either it was fished and not stapled so you can yank it out, or, you have the walls and ceilings open for a renovation so you can completely remove the cable.

2. In any major renovation where walls and ceilings are significantly open you should strive to remove as much disused wiring as possible from the cavities and to correct (by terminating in boxes) any wires previously abandoned in walls that cannot be removed entirely.

3. If you can't quite remove a wire entirely, because it is stapled, but you can at least see every inch of it by looking down joist bays and stud bays from one point of access to another, perhaps with the aid of a borescope, then you can remove what you can and cut, and leave behind, the segments that you can visually inspect but not remove. You should do this because later, if and when you renovate the wall or ceiling that is in the way, you'll expose a small segment of disused wire that can easily be removed, rather than just have the same problem forever.

4. In unfinished and outdoor spaces, disused wire that is significantly outdated and out of code should be removed proactively, following the above rules. Don't leave it just because you can. Although wires that are entirely disconnected are not governed by electrical code, if a future buyer or inspector for a buyer or lender sees old 2-wire cables or knob-and-tube strung around the house, they may regard it negatively, and may even scare off potential buyer with their ass-covering verbiage. Do yourself a favor and, following the above rules, get rid of it. Every. Last. Tube.

Answer 2

Pulling wires out makes sense in some cases. But disconnecting from the device and from the breaker is all you really need to do. Label the panel end so that future use is possible. Cap each end with a wire nut.

In the panel, unless the breaker space is going to be used for a different circuit, the breaker is normally turned off and left in place. There is no need to swap it for a filler plate.

I don't know the specific rule in code. But my gut feeling is that even if you are allowed to cover up the junction box because there are no longer any connected wires, the right thing to do is to not cover up (i.e., keep it accessible) unless you have actually removed the wires from the panel altogether.