Ask What Up to everybody? Welcome to another episode of Let's Ask Paul,
the podcast, where I, Paul Abernathy, attempt to answer all of your
pressing electrical questions submitted to me through our online portal over at Paul Abernathy dot
com. That's p A U l A B E r n A t h
y dot com. Now, feel free to submit me any electrical question you
have on the National Electrical Code, whether it's the twenty seventeen, twenty twenty
twenty twenty three or any earlier code cycle if you want. I don't mind
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download any software onto your computer. All right. So today's episode, I
wanted to kind of talk about something that I promised that I would talk about
that has to do with the single gang boxes and the exception that applies to
that. Whereas if you have a two and a quarter by four inch nail
up box, for example, and it has a tab in the back,
which again we'll talk about whether that's a knockout or whether or not that's considered
a securement method by the manufacturer of the box. We're gonna talk about that
today because again there's a lot of stuff out there about this, and I
have my own opinions of it and what I believe that most electricians do,
and so I want to talk about that and how it would be approached.
But the importance of this when people say is this is a petty thing that
that little tab on the back of those nail up boxes, whether it's a
car line or a context, they go, Paul, what's the big deal?
Well, the big deal about it is if you're using nonmetallic sheaf cable
that you typically if you're following the rules in three thirty four dot thirty for
nonmetallic sheaf cable, you're gonna need to secure that NM cable within twelve inches
if that has a clamp on the box. Well, the reason we're talking
about this is because there is an exception that's in the code that talks about,
well, what happens if there is no clamp on the box and the
boxes of a certain size, what do we do with it? And so
that's kind of the genesis of what we're talking about today. And I'm going
to get into some of the nuances. And again, I am totally aware
that there are two different camps on this, and there's people that swear it's
emphatically that it's it's it's simply a ko a knockout, and others that are
simply say no, the manufacturer says it's a clamp or it can be used
as a clamp. So we're going to kind of dig into my feelings on
this, and again, you can agree to disagree, that's totally up to
you, but we're going to look at it from a perspective of what does
the National Electrical Code say, Because at the end of the day, when
I post stuff like this, it's to make you think, because the HJ
is the one that has to make the decision, right, they're the one
that are going to look at this and say, okay, well, if
you're following the allowances, it has a clamp on it, then you can
go all the way up to twelve inches before you secure that cable to the
frame you member, Whereas if it's just a knockout, then you have an
allowance exception if you will that says okay, well you have to secure it
as it leaves that ko and goes up. It has to be within eight
inches. Now where's that in the code. So if you've got your code
books, what you're going to be looking forward and I'm in the twenty twenty
edition of the Nationaltrial Code. For this episode, you're gonna be going to
three fourteen dot seventeen B and that is boxes and conduit bodies. And then
under that you'll notice that there's a B two and it talks about conductors entering
through a cable clamp. Now it talks about where cable assemblies and with nonmetallic
sheathing are used. And again we're talking now NMB nonmetallic. It says she
shall extend not less than a core of an inch inside the box and beyond
any cable clamp, except that's provided in three hundred fifteen C and basically that's
where the conductors are coming in. Let's say a cable's coming in through a
raceway anyway, maybe for her physical damage protection things like that, then you
really kind of don't need to secure any cable to the box because it's literally
protected by being in the raceway. Right. It says the wiring method shall
be secured to the box or condraid body. So basically cable when brought to
a box gets secured to the box. How there's an exception to that.
An exception under three fourteen dot seventeen B two says where non metallic sheet cable
is used with single gang non metallic boxes. Okay, so key, it's
non metallic, not larger than two and a quarter by four inches, So
we're talking a typical single gang nail up box mounted in walls or ceilings,
and where the cable is fastened within eight inches of the box measured along the
sheath, and where the sheath extends through the cable knockout not less than a
quarter an inch, securing the cable to the box shall not be required.
Okay, so that's the exception. So many of the manufacturers out there make
single gag nail ups, and I use two of the main manufacturers, car
Line, which I believe is owned by dag on It. I'm drawing a
blank car Line overall, abb I think. And then Context is zonned by
Cantex and they both make boxes. Now, some of the single game,
most of the ones from from Cantex had this little V shaped insert where it's
kind of like has a little gap in it, and it's V shaped and
you push the cable in it and it literally presses against it and that will
hold and restrict the cable. So that's a clamp. And it's built into
the non metallic box, so obviously that's a clamp. So then the next
the staple. Let's just say that you're securing you wouldn't be using this exception
and you'd just be securing it within twelve inches now, you could have secured
it eight ten, eleven, seven six, it doesn't matter. It just
can't be more than twelve inches away. Right now, the question comes in
with the boxes, like the car Line box, and I've seen them in
two ways, right I've seen some of the car Line boxes with the knockout
in the back, and I'll call it a knockout because on some of them
there's no ribs or no, there's nothing. It's just a flat piece of
plastic. And the typical thing that electrician does is they'll take the backside of
their side cutters or screw driver or whatever and just pop that out. And
if it's totally removed, then obviously it's a KO. And so if that's
the case, then that's fine. As long as a quarter of an inch
of your sheathing goes into the box and you secure that cable within eight inches,
you're good to go. That's what the exception is all about. In
three fourteen seventeen B two the exception. Now, what we've got is that
Carlon also and they have multiple boxes, by the way, and if you
go look at Carlon, they will actually give you like four or five different
examples of their nail up boxes and things like that. And we're looking at
the single gang box again, the two and a quarter by four inch box
that has little grooves on the tab. So if you look at the literature
from Carlon and again this is where the reason I bring this up because I
know the practice of an electrician is just to pound it out and in that
the case, it's a knockout, and that's when this rule is going to
come into play, and you just secure it with it eight inches. Okay,
it's not going to change the world, but it is what it is.
Now. The manufacturer for those boxes that have the tabs that are to
also be used as a clamp actually states on their literature that it is contains
clamps. Well, now, some people say, well, spinning it to
the side is the intent of that, and I don't believe that is the
intent of that. I believe that it is. The intent is to You're
only supposed to remove one side of the connecting membrane for that tab. You
move one side of it, and then the tab is still there. Even
though you remove one side, it just still hangs there because of the tension
from the other tabs the other connecting membrane. So what happens is you simply
break one side of the tab and the tab will swing in and you simply
push the cable inside and that will act as a clamp when you try to
pull it back out. Now, I know that people have tried this and
done this, and some say that it doesn't restrict the pulling it out and
I get that, but from the manufacturer's perspective, they believe that it puts
enough tension on there that it's not going to pull out, and thus they're
going to call it a clamp. Now, the HJ may come along and
say, I don't think so, I think it's a ko and that's in
their prerogative. But when you provide them with the information from the manufacturer,
who again, at the end of the day, one ten, dot three,
b Okay, all of this stuff that tab is part of the manufacturing
process. If the manufacturer gives you something. And that's why I always tell
people, don't be afraid to reach out to the manufacturer, because the manufacturer
knows their products better than anybody. Don't try to outsmart the manufacturer, all
right. They're the ones that are going to take the liability if they tell
you to do something that's wrong. So they're not going to do that.
They're going to attempt to give you the best information they can. So I
don't know why people find it such a struggle to simply make a call to
a manufacturers. It's a simple process. And so if the literature that is
provided says that these are clamps, then me as an inspector, and I
have been an inspect I'm gonna look at it and i'm gonna go, Okay,
if you say it's a clamp, it's a clamp. It's fine.
Um, and I'm gonna say that's fine. Go up to twelve inches.
If you knock it all the way out, then I'm going to say no,
I need to have a securement within eight inches. It's it's pretty straightforward.
All I have to do is look at it now. Back in the
day, when when I installed the single nail boxes, I'm gonna be be
honest with you, I just pounded out that that that that tab and it
was gone. I'm really, I mean not just it was gone. And
in that case, it's a ko and I'm gonna put these staple within eight
inches. It's not that big of deal. But the reason I brought this
up is because it became a big deal when a gentleman posted a question about
it and I tried to explain it and he went just a yes or no
answer. Well, all of you know, you don't come to my forums,
you don't come to my websites for a yes or no answer. You
get the in depth analysis at the end. Of the day. The HJ
is the one that's going to have to make the call. And if the
manufacturer, in their literature, remembering they're the ones that produce the product,
if they state that it has a clamp and it is the box you're using,
then whether you like it or not, it's a clamp. As far
as in the eyes of the code. It's a one ten three B.
It's the manufacturer's statement, that's what it is. If it's all knocked out
or removed, then it's a KO. Okay. So this really only comes
into play on a single game box. And as I tell people all the
time, you do you if you feel so passionately that it's a tap and
it's a ko, then make sure that you're diligently securing that cable within eight
inches because that's you need to practice what you preach. Right. If you
feel it's a clamp and you do it at twelve inches and an inspector rejects
you and you give them the document from the manufacturer that says it is considered
a clamp on these style of boxes, then he can say, well,
it doesn't look like a clamp to me, and then they're gonna start going
into the code and say, well, it says it has to secure well
in the eyes of the manufacturer, and they're testing it does secure. There's
enough tension on it that they feel it secures it. I do tell people
also, we're following the intent of the code. We're not overanalyzing it,
and we're not recreating the wheel here. Do you think that in a wall?
If you have a nail up box and you remove one connecting edge of
the clamp so that it's still there like a swinging door, you push in
the cable. Okay, you don't pre push the tab, man, You
literally cut the tab and then you push the cable in. It should catch
it enough to not pull out. It should have enough resistance on it.
Do you really think it's going to move in the wall? I mean really,
So we can argue the semantics of eight inches or twelve inches, but
it's all about the tab. Now again, if you're move the whole thing,
okay, there you go, secure it within eight inches. If you
leave the tab, you only could move one side of the tab. This
two can. Usually it has the tab is connected on opposite sides with a
little membrane to the box, and you simply break that tab on one side.
Then it acts as a spring retention. And that's what the manufacturers intended,
and that's why they put on their literature that is considered a clamp,
whether you agree with it or not, whether you do your own testings,
and it pulls out again if it's in the wall or people going to be
pulling on it. If you're still securing the cable within eight inches or twelve
inches, is it going to move anywhere? No, it's not, and
we all just be thankful that people are even securing anything anyway. So because
I've seen some of the work on TikTok and Instagram and tradehounds, and it
shocks me anyway that things don't burn down every day. So I would not
sweat the small stuff, but I would use my golden rule here, as
if you knock a k out ko all the way out on a two and
a quarterby four inch nail up box, then you need to secure that cable.
What they'd inches if you remove the tab just one side and the tab
is still there and it's kind of like a hinged door and you push the
cable in and a tab is still intact, then I'm going to call it
the clamp as long as the manufacturer has literature that says it's a clam,
and Carlins do say it's a clamp. Now, when it comes to contexts,
they're designed that V shape design makes it very evident that it's going to
hold the cable, so it's clamp. The others will say, well,
the code says it has secure the cable. Right, So I'm sitting there
going okay, Well, at the end of the day, when you're looking
at the exception, it's it's only talking about when it's a KO. Other
than that, as long as that tab is touching that sheathing and that sheathing
is against the box, then it's connected to the box. It's secured to
the box. Now, how secure do you want it to be? Okay,
you know you can get into the semantics of that. Again, at
the end of the day, it ain't going anywhere, so no sense in
losing any sleep over that, right, So summarize this. I'm gonna giving
you my opinion that if you go to this nail up box and you knock
that knockout out of that two and a quarterback four inch nail up box,
then it's a KO. Make sure you put us strap or staple or whatnot
within eight inches. If you want to go in and cut out one side
of that tab so that still has the spring retention on it, and you
push that cable into it to make sure that you can go all the way
up to twelve inches. Because the manufacturer calls that a clamp, then you
do, you go and you can secure it to twelve inches. Me personally,
I'm going to secure the damn thing within eight inches so that I don't
have to worry about an inspector saying it's a knockout or a clamp. What's
the big deal four inches? Okay, I'm just going to do it at
eight inches and I'm moving on. And that's the way I always did it,
regardless it's about it. I didn't never went up to twelve inches,
and most of the time I was probably closer than eight inches. But anyway,
that's my thought on it. The debate can roll on. You can
call it a tab, you can call it a ko you can call it
whatever you want. If the manufacturer calls it a clamp, and there is
a specific way, and there are instructions on the internet how to remove one
side of that tab with a razor knife. Then it becomes a clamp based
on that manufacturer's testing, and that's part of their listening and that's why they'll
put in there that it's a clamp. So moral of the story, don't
be afraid to reach out to your manufacturer, get some clarification if there's any
question about it, to make easier mind, to make you feel better.
But at the end of the day, it could go either way. It's
the hj's call. They have that authority. I would secure it within eight
inches and you don't have to worry about it either way. All right,
all right, folks, that's all I got for that episode. You can
agree to disagree. If you have any questions that you want covered here at
Let's Ask Paul, just go to Paul Aberne at the TOM I love to
hear the questions from you. We will be answering a lot of questions also
live on our Fast Tracks Live that starts June twenty eighth at seven thirty pm
Central Time. Makes You can join us on all of your favorite social media
platforms that we're attached to, so make sure you check it out. Until
next time, folks, Stay safe, God bless Ask