Making a 3 way switch a 4 way

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Re: Making a 3 way switch a 4 way

Hey Bob, what are we a "tag-Team"?!?

Ok..tag, you're it, you go first, Let me know if you need me!

:)

Dave
 
Re: Making a 3 way switch a 4 way

Wwebb posted April 05, 2005 07:31 PM
you ARE violating 300.3.
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2002 NEC 300.3(B) Conductors of the Same Circuit. All conductors of the same circuit and, where used, the grounded conductor and all equipment grounding conductors and bonding conductors shall be contained within the same raceway, auxiliary gutter, cable tray, cablebus assembly, trench, cable, or cord, unless otherwise permitted in accordance with 300.3(B)(1) through (4).

2002 NEC 300.3(B)(3) Nonferrous Wiring Methods. Conductors in wiring methods with a nonmetallic or other nonmagnetic sheath, where run in different raceways, auxiliary gutters, cable trays, trenches, cables, or cords, shall comply with the provisions of 300.20(B). Conductors in single-conductor Type MI cable with a nonmagnetic sheath shall comply with the provisions of 332.31. Conductors of single-conductor?type MC cable with a nonmagnetic sheath shall comply with the provisions of 330.31, 330.116, and 300.20(B).
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And 300.20(B) is all about cutting slots in ferrous enclosures that have one conductor entering per hole, so 300.3(B)(3) is the exception that allows the method Walt is describing.
 
Re: Making a 3 way switch a 4 way

300.3(B)states: "unless otherwise permitted in accordance with 300.3(B)(1) through (4). Where do you see, in (1) through (4) anything that would refer to an exception in this case. Certainly the references to 300.20(B)are not what you mean. Have you READ that article? It, in no way, is meant to be applied to a romex installation.
I think this is a case of little forethought leading to excessive afterthought.
 
Re: Making a 3 way switch a 4 way

Johndeereman, Jim was making the point that the NFPA Handbook is a book of opinions just like we are giving here and he is 100% correct. The NFPA writes and publishes the NFPA NEC Handbook but they do not write the NEC. Just because it is written in a book, even the NFPA NEC Handbook, does not make it so. A point of fact is the disclaimer in the front of the handbook that says that it is opinion only.

With all that said, the NFPA NEC Handbook is very good but the words in the NEC must stand on their own. :D
 
Re: Making a 3 way switch a 4 way

wwebb posted April 05, 2005 07:56 PM
Where do you see, in (1) through (4) anything that would refer to an exception in this case.
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The 2002 NEC? bold italics in my quotes above, especially the word cables in 300.3(B)(3).

[ April 05, 2005, 08:06 PM: Message edited by: al hildenbrand ]
 
Re: Making a 3 way switch a 4 way

Theory = Opinion

It is funny how we base so much off of a book of opinions. :D Thats my opinion. You know what they say about opinions though. They are like _______, everyone has one. Mine just isn't important enough to get in the code book. BPHgravity has a good quote at the end of his signature line about theory and opinions. And its from the code book.

[ April 05, 2005, 08:32 PM: Message edited by: aelectricalman ]
 
Re: Making a 3 way switch a 4 way

Originally posted by aelectricalman:
Theory = Opinion

It is funny how we base so much off of a book of opinions. :D Thats my opinion. You know what they say about opinions though. They are like _______, everyone has one. Mine just isn't important enough to get in the code book. Bphgravity has a good quote at the end of his signature line about theory and opinions. And ah, its from the code book.
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I just do my job day in and day out and at the end of the day, I let the inspector interpret his collection of thoughts and decide whether my job is done correctly. In the end, every AHJ is different. Hell, the same AHJ may be different on any given day. OK, breath........... Shew. Done
 
Re: Making a 3 way switch a 4 way

Where are you finding in the Handbook that this is an acceptable installation?

300.20(B). is speaking about single conductors. Here we are talking about using two runs of 14/2 to feed a 4 way switch.

(B) Conductors of the Same Circuit. All conductors of the same circuit and, where used, the grounded conductor and all equipment grounding conductors and bonding conductors shall be contained within the same raceway, auxiliary gutter, cable tray, cablebus assembly, trench, cable, or cord, unless otherwise permitted in accordance with 300.3(B)(1) through (4).

This general rule remains consistent with electrical theory; that is, to reduce inductive heating and to avoid increases in overall circuit impedance, all circuit conductors of an individual circuit must be grouped. Similar requirements are found in 300.5(I).

To install this in the manner outlined it would be possible to have current in one conductor of one cable and current in one conductor of the other. A very bad situation.

300.5 (I) Conductors of the Same Circuit. All conductors of the same circuit and, where used, the grounded conductor and all equipment grounding conductors shall be installed in the same raceway or cable or shall be installed in close proximity in the same trench.
 
Re: Making a 3 way switch a 4 way

JW,

Knob & Tube is a single conductor.

More importantly, what about 300.3(B)(3)?
 
Re: Making a 3 way switch a 4 way

Originally posted by walt763:
Quick question on converting a 3 way to a 4way. Would it be a against NEC 300.3 to loop the travellers down to the 4ways in a basement using 2 wire NM and come back up to the same box that the 3way is located. In essence it would be extending the travellers to add in the 4 way swithes. The hot and the fixture are fed into and out of this box that the 3 way is now located. The inspector says it would not be code and would have to have 3 wire cable going through all the boxes. :confused:
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what Knob and Tube?
 
Re: Making a 3 way switch a 4 way

JW,

I agree with your point about inductive heating being an issue in EMT, rigid, etc., but this is about a nonmetallic cable sheath. When the cable sheath is not going to heat from having only one current carrying conductor inside it, 300.3(B)(3) says all we have to do is pay attention to the enclosure that the cable ends at. If the enclosure is ferrous, then we follow 300.20(B) and introduce cuts in a manner to reduce overall eddy current density.
 
Re: Making a 3 way switch a 4 way

ok..... then run one 12/4 romex
re-identify the conductors.

More than one way to skin a cat.....
 
Re: Making a 3 way switch a 4 way

My opinion from reading Article 300.3 is that 300.3(B) is refering to individual conductors in a seperate raceway. It is clearly stated in 300.3(B)(3)that this type of instalation is permitted.
300.3(B)(3) said:
Conductors in wiring methods with a nonmetallic or other nonmganetic sheath, where run in seperate raceways, auxillary gutters, cable trays, trenches... Shall comply with the provisions of 300.20(B).
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300.20 refers to the induction between conductors, and the metalic raceway, since NM-B in this situation is (unless the house has steel studs) stapled to wooden studs, and induction is not a concern.

[ April 05, 2005, 10:51 PM: Message edited by: bensonelectric ]
 
Re: Making a 3 way switch a 4 way

300.3 (B) (3) Nonferrous Wiring Methods. Conductors in wiring methods with a nonmetallic or other nonmagnetic sheath, where run in different raceways, auxiliary gutters, cable trays, trenches, cables, or cords, shall comply with the provisions of 300.20(B). Conductors in single-conductor Type MI cable with a nonmagnetic sheath shall comply with the provisions of 332.31. Conductors of single-conductor Type MC cable with a nonmagnetic sheath shall comply with the provisions of 330.31, 330.116, and 300.20(B).

300.20 (B) Where a single conductor carrying alternating current passes through metal
332.31 Where single-conductor cables
330.31 Where single-conductor cables
330.116 Sheath.

Each section that 300.3 (B) (3) refers to is for single conductor. The original post is for two conductor cable.
300.3 (B) and 300.5 (I) both clearly state that all conductors of a circuit have to be installed in the same cable or raceway. He is installing a cable assembly with multi conductors therefore they SHALL BE in the same cable or raceway.
:)
 
Re: Making a 3 way switch a 4 way

Matt,

You left off the two most important words at the end of that quote, "trench, cable, or cord.
 
Re: Making a 3 way switch a 4 way

JW,

When both travellers are present in one 14/2, only one of them is a conductor at a time.
 
Re: Making a 3 way switch a 4 way

Well, with the exception of the travelling bus threeway, and fourway, in certain switch positions.
 
Re: Making a 3 way switch a 4 way

JW,

Your references to 330.31 & 330.116 are for MC cable and not germane to the topic that you reminded me of when I refered to K&T.

Edit to correct spelling of germain to germane. -- Al

[ April 05, 2005, 11:46 PM: Message edited by: al hildenbrand ]
 
Re: Making a 3 way switch a 4 way

One last post before I go to bed. I got to get up early in the morning. Think this through.
If it was a three way three wire dead end switch current would be going and coming in same cable or two conductors hot at the same time. If it was fed through then the neutral would be present for the return current.
As described current can be going down to 4 way in one cable and returning in the other, a definite NO NO!!!
 
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