Neutrals one per hole?

[Joseph Alexander]

Does anyone know for certain that this code first appeared in the 2002 NEC: 408.21
I am doing a home inspection repair list and the H.I. is complaining about an older Square D panel. He is stating that you can only have one neutral per termination.
I know this is correct for now, but it was not when this panel was placed (At least I am fairly sure)

Alex

 

[infinity]

The requirement preceded the inclusion of 408.21 in the NEC by decades as part of the listing of the panelboard. They only added the wording into to the NEC because it was a somewhat unknown fact that it was already prohibited by the listing.

 

[kwired]

The requirement preceded the inclusion of 408.21 in the NEC by decades as part of the listing of the panelboard. They only added the wording into to the NEC because it was a somewhat unknown fact that it was already prohibited by the listing.

Could be, but the instructions would have had to specifically mention grounded or grounding conductors and where it applied. Many neutral bus bars have been rated for multiple conductors for a long time, but maybe the instructions only allowed multiple conductors for equipment grounding purposes only? I remember reading instructions on a few different panelboards and determining that two conductors per terminal was fine, and don't recall ever reading that it was limited to equipment grounding conductors only.

Of course on a non service panel or a then allowed separate building with no separate equipment grounding conductor, you couldn't have equipment grounding conductors mixed with the grounded conductors.

 

[cowboyjwc]

Could be, but the instructions would have had to specifically mention grounded or grounding conductors and where it applied. Many neutral bus bars have been rated for multiple conductors for a long time, but maybe the instructions only allowed multiple conductors for equipment grounding purposes only? I remember reading instructions on a few different panelboards and determining that two conductors per terminal was fine, and don't recall ever reading that it was limited to equipment grounding conductors only.

Of course on a non service panel or a then allowed separate building with no separate equipment grounding conductor, you couldn't have equipment grounding conductors mixed with the grounded conductors.

I would agree with this. Used to say something like 2-#12. They had to be the same gauge wire.

 

[don_resqcapt19]

... Many neutral bus bars have been rated for multiple conductors for a long time, but maybe the instructions only allowed multiple conductors for equipment grounding purposes only? ...

I don't think that the instructions on the panel ever permitted more than one grounded conductor per hole. Many permit two or three EGCs per hole.
I am not sure how long the rule has been a part of the UL standard for panels. The following is part of the substantiation for proposal 9-113 for the 2002 code cycle.

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. ...

 

[kwired]

I don't think that the instructions on the panel ever permitted more than one grounded conductor per hole. Many permit two or three EGCs per hole.
I am not sure how long the rule has been a part of the UL standard for panels. The following is part of the substantiation for proposal 9-113 for the 2002 code cycle.

I could have been wrong, but just wanted to bring up what I thought was allowed at that time. Now I am going to have to find a panel I know is old enough and read the label carefully. Should see one tomorrow, now I need to remember to look at the instructions.

 

[PetrosA]

In Southeastern, PA they still haven't gotten wind of the change In almost every house panel I've opened less than 20 years old, they land the neutral and ground together in one hole. I guess it speeds up putting a panel together, but it sure looks amateur to me :rant: And... they all have final inspection stickers.

 

[infinity]

I could have been wrong, but just wanted to bring up what I thought was allowed at that time. Now I am going to have to find a panel I know is old enough and read the label carefully. Should see one tomorrow, now I need to remember to look at the instructions.

If you find one post a photo.