3-way switch loops

[al hildenbrand]

Re: 3-way switch loops

Well we disagree here and I think you enjoy causing confusion.

 

[George Stolz]

Re: 3-way switch loops

Bob,

Well now you've gone and done it, I walked out to my truck and retrieved a four-gang. Here's a picture of the interior of it:
Click here for the picture. It's huge, I edited it out of the post!

As you can see, the box is listed for use with a "C" or "K" clamp only.

What is a "K" clamp?



[ July 10, 2005, 01:28 PM: Message edited by: georgestolz ]

 

[iwire]

Re: 3-way switch loops

Originally posted by georgestolz:
Apparently, the manufacturer and the UL consider the black tab in the back of the box to be a "clamp." Why don't you?

Simply being a clamp is not enough, it has to be an internal clamp before counting it applies.

314.16(B) (2) Clamp Fill. Where one or more internal cable clamps, whether factory or field supplied, are present in the box, a single volume allowance in accordance with Table 314.16(B) shall be made based on the largest conductor present in the box. No allowance shall be required for a cable connector with its clamping mechanism outside the box.

If the box in question is like the one in the photo bucket I would count the clamp, it is internal to the box and therefore must be counted.

In this area most PVC boxes have no internal clamp they have a clamping device that is made up of the enclosure wall, that would not be an 'internal' clamp IMO.

 

[iwire]

Re: 3-way switch loops

Originally posted by al hildenbrand:
I've missed you, too. :roll:

[ July 10, 2005, 02:04 PM: Message edited by: iwire ]

 

[iwire]

Re: 3-way switch loops

Originally posted by al hildenbrand:
Also, Bob, you didn't answer the question I returned to you. . .What about neutrals as current carrying conductors?. . .

No I did not.

 

[iwire]

Re: 3-way switch loops

Originally posted by al hildenbrand:

Posted by IWire
It's pretty straight forward.

Yup, if there are internal clamps, count'em. Just as you chose to say don't count'em:

If the clamps are internal I do count them, when they are external of flush with the enclosure I do not count'em.

It amounts to nothing as the same area of the code counts a GFCI outlet the same as a $.50 junk SP 120 switch in regards to fill.

 

[al hildenbrand]

Re: 3-way switch loops

310.15(B)(4). . . Interesting. That's why you recoiled.

That escaped me entirely, given that we are in a thread about box sizing a switch loop on a 120 V branch circuit.

I appreciate the compliment on being able to inflate a thread, but I think I am really only trying to talk a topic through. . .

Sorry I missed the other thread. Which one was it, out of curiosity (not with the intent of reviving it. . .honest.)

 

[allenwayne]

Re: 3-way switch loops

I have always taught my helpers that with 3 way 1/2 switched receptacle outlets or 3 wayed fan/ light combo`s to switch and feed from the same location.Yes you must take box fill into consideration.Those fiber 4x4 bakelite boxes we use in rare cases since the claping device must be counted but the p ring used has cu.in. capacity listed on it.Most homes here are block 1st floor and stud above that.It is so much easier to drop a 3 wire to switch location and make it up at what is usually a multigang box.
To me the simple method of feeding from one location and switching from another location brings up more issues than dead ending a switch.
Lets look at afci circuits,there might be several points along the circuit where neutrals might be tied into non afci circuits K.I.S.S.T.I.T. ( keep it simple stupid think it through)Just my opinion I know everyone here thinks there`s is the correct one Electricians have the biggest egos of any trade we all think we are the best

 

[iwire]

Re: 3-way switch loops

Originally posted by al hildenbrand:
310.15(B)(4). . . Interesting. That's why you recoiled.

That escaped me entirely, given that we are in a thread about box sizing a switch loop on a 120 V branch circuit.

My fault for assuming you had 310.15(B)(4) in your mind.

 

[George Stolz]

Re: 3-way switch loops

Originally posted by iwire:
In this area most PVC boxes have no internal clamp they have a clamping device that is made up of the enclosure wall, that would not be an 'internal' clamp IMO.

Are you talking about the blue Carlon boxes, where it has a large flap in the back of the box?

Does it enter the box, or accomplish it's clamping function outside of the box?

By 314.16, it's either in or out. If it's in, it's counted.

We must be talking about two different boxes. The ones I'm thinking of snap off really easily in the cold...

These things?

 

[iwire]

Re: 3-way switch loops

Originally posted by georgestolz:
The clamps on the boxes may be cast at the same time as the box, but they're still clamps! Otherwise, they'd violate 314.17(C). Or am I way off base?

Let me ask this of you.

What do you consider an external clamp?

 

[curt swartz]

Re: 3-way switch loops

George, the clamps in the Carlon boxes are molded into the box and are already part of the cubic inch rating marked on the box. The clamps in the Allied fiberglass boxes and metal boxes are separate accessories and not part of the cubic inch rating marked.

 

[George Stolz]

Re: 3-way switch loops

Originally posted by iwire:

Originally posted by georgestolz:
The clamps on the boxes may be cast at the same time as the box, but they're still clamps! Otherwise, they'd violate 314.17(C). Or am I way off base?

Do what you want, I don't use plastic junk.

I too live a plastic-free lifestyle.

 

[iwire]

Re: 3-way switch loops

Sorry George we will have agree to disagree on this one.

Take a look at Curt's post.

 

[physis]

Re: 3-way switch loops

I used to not like plastic but I've changed my mind over the years. What's the problem with it?

 

[iwire]

Re: 3-way switch loops

OK one more

Originally posted by georgestolz:
But 314.16 doesn't care about anything but where it's clamped.

Where do you see that?

I see that 314.16 'cares' about the location of the clamp, not where it performs the act of clamping. I think you may be reading it how you want it to read.

(2) Clamp Fill. Where one or more internal cable clamps, whether factory or field supplied, are present in the box, a single volume allowance in accordance with Table 314.16(B) shall be made based on the largest conductor present in the box. No allowance shall be required for a cable connector with its clamping mechanism outside the box.

There is no mention of where the clamping takes place.

 

[physis]

Re: 3-way switch loops

Bob, I haven't been following this but what about:

314.16(B)(2)..............No allowance shall be required for a cable connector with it's clamping mechanism outside the box.

Edit: And I just noticed that you even have the reference.

Am I misunderstanding this, wouldn't be the first time.

Edit again: This

is exactly what's being described.

</font>

• <font size="2" face="Verdana, Helvetica, sans-serif">A connector</font>
• <font size="2" face="Verdana, Helvetica, sans-serif">with it's clamping mechanism outside the box</font>

<font size="2" face="Verdana, Helvetica, sans-serif">

[ July 10, 2005, 07:39 PM: Message edited by: physis ]

 

[iwire]

Re: 3-way switch loops

Originally posted by physis:
I used to not like plastic but I've changed my mind over the years. What's the problem with it?

Actually nothing when used with NM and wood studs.

With MC and metal studs the blue plastic clashes with the shiny metal.

 

[physis]

Re: 3-way switch loops

I haven't got to work with metal studs yet.

 

[George Stolz]

Re: 3-way switch loops

Originally posted by iwire:
There is no mention of where the clamping takes place. [/QB]

(2) Clamp Fill. Where one or more internal cable clamps, whether factory or field supplied, are present in the box, a single volume allowance in accordance with Table 314.16(B) shall be made based on the largest conductor present in the box. No allowance shall be required for a cable connector with its clamping mechanism outside the box.

Funny, it saying "if the clamping is taking place outside the box, no allowance is required."

I am so confused by your read on this. It seems so clear to me. One of us is very wrong. I hope to discover for sure who it is, so I hope you don't run off (i.e. agree to disagree.)
----------
As for Curt's statement, I'd love to see some evidence of this, for curiousity's sake. But it really had no bearing on the meat of our discussion. I just peeked back at my Allied four-gang, and it doesn't take the clamps into account. It states that "30 #14" conductors can be present in the 60 cu in box, meaning that the one conductor that came with the box (the clamps) wasn't subtracted from the math.