Speaking of double lugging

This is a SQ.D type QO panel with nuetral bars all over the place, lots of room, and what does the electrician do?

IMG_0023 (Small).JPG IMG_0024 (Small).JPG

The problem is, this is the first house I’ve inspected in this townhouse subdivision(there are already 25 built), and I am going to raped over calling out double lugged neutrals and grounds. The AHJ allows this to occur in Franklin County.

:roll: tg

Have you asked the AHJ if this is allowed, or are you getting this information second-hand?

Regardless, you should write it up just as you see it.

Ditto what Jeff said.

It seems unlikely that any AHJ has actually overruled the section of NEC 110.14(A) that states…Terminals for more than one conductor…shall be so identified. The AHJ’s inspector may be letting this slide…but he’s wrong (unless he can show you something “official” in writing).

Square-D generally lists the neutral lugs for up to 2 grounding conductors, but every neutral should be on its “ownsome”.

Stick to your guns! It would be a simple fix anyway.

In lighten me as to why this is an issue? Could it be that, circuits would be more difficult to isolate, having neutrals sharing the same termination point?

In this case, the applicable section would be 408.21

**408.21 Grounded Conductor Terminations. **Each grounded conductor shall terminate within the panelboard in an individual terminal that is not also used for another conductor.

Ok thats the NEC code correct? How do you explain to the client about the defect, if they ask, without quoting code. We are not code enforcers.

Thanks Jeff. Don’t think I have ever noticed that section before. Even clearer.

This is from Paul in another thread. This says it pretty clear for me.


Intent: This new section should ensure that grounded (neutral) conductors terminate within the panelboard to an individual terminal. This has been a UL requirement (UL Std. 67 – Panelboard Standard) for some time, and the addition to the NEC is intended to bring this information to the installers. Technically, this is covered by 110.3(B), which requires all equipment to be installed in accordance with the manufacturer’s installation instructions and markings, but nobody knew it existed. UL Std. 67 (Panelboard Standard) permits up to three 10 AWG equipment grounding conductors to terminate on a single terminal, if the terminal is marked for this purpose.

The intent of this requirement is to ensure that the grounded (neutral) conductor of a multiwire branch circuit is not momentarily disconnected, which could result in the destruction of electrical equipment and fires from overvoltage.

My Comments - As we have talked many times regarding this and have posted things as well, it is always important to know exactly where the reason for reporting it comes from. This is posted courtesy of Mike Holt Enterprises

Gary…my normal explanation is that neutrals are current carrying conductors and it’s a “quality of connection” issue. That easier to understand than the other issue, which is a possible open ground if modifying one of the circuits.

I almost never use the “code” word either, but we are very much “code informers” when it comes to electrical safety. Where else do you get 14AWG is not OK on a 20-amp breaker, etc. Of course, we just make recommendations based on code and don’t actually “enforce” anything.

Jeff, are you calling out the double lug neutral/ground buss as information or actually recommending the client contact an electrician. It’s so common in all the older homes I inspect. I see it almost everyday. Every electrician I talk to about it, won’t call it out or recommend repair as long as the both wires are sized the same.

It really depends on the age of the panel/home. If it’s a relatively new installation, I’ll call it out as in need of repair or correction.

In older homes, I recommend correction based on current standards (like GFCI upgrades). Even though most “experts” seem to agree that this has never really been allowed unless the bus bar was listed for multiple conductors. It has only recently been addressed specifically.

408.21 Grounded Conductor Terminations…Remembers guys this Grounded Conductors is the Neutral…as previously stated in no cases should the Neutral wires be double lugged…like jeff said in most panels the equipment grounds can be…or atleast that is something I would not call out unless they are two different size AWG wires…otherwise not that large of an issue with the Equipment grounds…BUT not allowed again on the Neutrals…

Yes I am really concerned with double lugs on neutrals .
Lets for a moment think that one has a 2 amp load and the other has a 10 amp load .
Now some one in the panel decides to correct the double lugs now we have a
Hugh unbalance on the 10 amp side we have very low voltage and on the
2 amp side we have a very high voltage and you can be sure what ever is
on the 2 amp side is in an immediate destruct mode.
The other thing is many people think that there is no problem working on neutrals .
This is wrong neutrals can be just as deadly as feed wires.
Roy sr

Which is why they should be defered to electrical contractors who know how to do these changes without having issues…:slight_smile: not something I would let the DIYer do…however it is their house and their life…I am only the " Voltage Bender "…I can’t TELL them what to do…only suggest it…lol

Y’all might want to read this Log from the NEC code panel: It has never been allowed to double lug neutral wires (grounded conductors).

UL Standard 67 has never accepted it. UL Standard 67 is part of the manufacturer’s instructions. The code required that panelboards be installed in accordance with the manufacturer’s instructions. So it was kind of a round about way to get there. Who ever read the manufacturer’s instructions or UL Standard 67.

This clarifys why it is now directly in the code.

Jim Katen, a VERY knowledgeable inspector from Oregon was the source when I first found it, but it’s in several places.

Log from the NEC Code Panel, regarding the new clarifying language in the Code.

(Log #3287) 9- 113 - (384-21 (New) ): Accept

SUBMITTER: James T. Pauley, Square D Co.

RECOMMENDATION: Add a new 384-21 to read as follows:

384-21. Grounded Conductor Terminations. Each grounded conductor shall terminate within the panelboard in an individual terminal that is not also used for another conductor. Exception: Grounded conductors of circuits with parallel conductors shall be permitted to terminate in a single terminal if the terminal is identified for connection of more than one conductor.

SUBSTANTIATION: This revision is needed to coordinate the installation requirements with a long standing product standard requirement. Clause 12.3.10 of UL 67 (Panelboards) states “An individual terminal shall be provided for the connection of each branch-circuit neutral conductor.”

The requirement has been enforced in the past by a close review of the manufacturers markings and by NEC 110-3(b). However, since it is a rule that specifically effects how the installer can make connections, it is important that it be in the NEC.

Even with the manufacturers markings, inspectors still indicate that they see a number of panelboards installed with two (or more) branch circuit neutrals under one terminal or they see an equipment grounding conductor and neutral under the same terminal.

There is very good rationale for the requirement in the product standards. Doubling up on the neutrals creates a significant problem when the circuit needs to be isolated. In order to isolate the circuit, the branch breaker is turned off and the neutral is disconnected by removing it from the terminal. If the terminal is shared with another circuit, the connection on the other (still energized) circuit will be loosened as well.

This can wreak havoc, particularly if the neutral is part of a 120/240V multi-wire branch circuit. Also, the neutral assemblies are not evaluated with doubled-up neutrals in the terminals. The connection of a neutral and equipment grounding conductor creates a similar issue.

One of the objectives of the particular arrangement of bonding jumpers, neutrals and equipment grounds is to allow circuit isolation while keeping the equipment grounding conductor still connected to the grounding electrode (see UL 896A - Reference standard for Service Equipment). When the neutral is disconnected, the objective is to still have the equipment ground solidly connected to the grounding electrode.

If both the neutral and grounding conductor are under the same terminal, this cannot be accomplished. This addition to the NEC does not change any product or permitted wiring arrangement from what it is today.

It will however, it will help installers to avoid wiring the panel in violation of 110- 3(b) and then have to contend with a red-tag from the inspector. The code language is proposed in a fashion to allow consistent enforcement of the provision by the AHJ.

Although the UL wording is adequate for the product standard, it is important that the NEC language is as clear and unambiguous as possible. This is the reason for specifically noting that the terminal cannot be used for another conductor.

Furthermore, the code requirement has been worded to make sure that both branch circuit and feeder neutrals are covered since it is not uncommon to have feeder breakers as well as branch breakers in the panelboard (the issue for the neutral is the same regardless of branch or feeder).

Also, the term “grounded conductor” is used to be consistent with the code terminology and to recognize that not all grounded conductors are neutrals.
An exception has been proposed to avoid any confusion relative to parallel circuit arrangements. In these instances, multiple neutrals could be in a single terminal if the terminal has been identified as acceptable for multiple conductors.





“Exception: Grounded conductors of circuits with parallel conductors shall be permitted to terminate in a single terminal if the terminal is identified for connection of more than one conductor.”

Could someone expand on this? I would like to understand this exception better. Thanx.

Jeff asked " Have you asked the AHJ if this is allowed, or are you getting this information second-hand?"

I have had this conversation with the AHJ inspector that covers this area of the county. As recently as yesterday.

Erby’s ref to the NEC log has been sent to this individual (who said previously he would discuss it with his boss) .

Thanks for the great responses - rape averted, and knowledge gained.