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RSE Master Electrician
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@HertzHound, that’️s not the way I read it. 300.20(b) is referring to single conductors, not conductors of a multiwire cable.

The NEC is confusing. 300.3(b)(3) Say's it's allowed as long as 300.20(b) is followed. Yes 300.20(b) is for single conductors but it's 300.3(b)(3) that got you there.



(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).
I disagree. Those rules and exceptions are not meant to be used when running multi-wire cables, they are for single conductor. The CEC also has similar codes for when doing that.
@Dennis Alwon, what is your interpretation of these NEC articles? Can a circuit be split up into different multi wire cables for three way switching and are the NEC articles posted allowing it?
 

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36th year apprentice & Floor Sweeper
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Maybe we can get Cricket to throw in an ET mug to to the correct interpretation? :vs_OMG:
 

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So who sells 14/4 loomex?
I dont know about your area ever sell 14/4 verison loomex .,,

but I know in USA and my country they can get it pretty easy if you know where to get it. some of the big box store still carry it but cost more than just run of mill 14/3 verison is.

sometime you need a lead time if you know you will use it a bit.

Now to answer other question .,,

can run pair of NM ( loomex ) cables to the switch box or lumainaire box ?.

Yes it done pretty often in old days before the XX/3 NM or loomex is common but you really have to watch how it connected cuz there is not much clue to give out so pay attention to the travelers.

I think Dennis will agree with me with old set up. but currentaly it kinda super rare unless special situation arise.
 

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RSE Master Electrician
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Yes it done pretty often in old days before the XX/3 NM or loomex is common but you really have to watch how it connected cuz there is not much clue to give out so pay attention to the travelers.

I think Dennis will agree with me with old set up. but currentaly it kinda super rare unless special situation arise.
Of course it was done in the past before 3 wire was around. Knob and tube is still seen in older houses today but that does not mean we can wire receptacles and switches with single conductors today.

New installations must follow new code and in Canada, all conductors of a circuit (if using multi conductor cable) must be in the same cable. 12-106(1)
 

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Maybe they can get the logo on a 20oz Yeti tumbler. Id buy some of those.
 

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Run a 2-wire to the first box and then to the second. That will give you a neutral in each box to satisfy the neutral requirement. Then a 3-wire between the same two boxes will give you two travellers and a switch return or a hot and 2 travellers depending on where you start your switching from.

From where you end your switching, a 2-wire to your load. Or 3 if you want to take the hot.

Or use 4 wire BX.
 

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RSE Master Electrician
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Run a 2-wire to the first box and then to the second. That will give you a neutral in each box to satisfy the neutral requirement. Then a 3-wire between the same two boxes will give you two travellers and a switch return or a hot and 2 travellers depending on where you start your switching from.

From where you end your switching, a 2-wire to your load. Or 3 if you want to take the hot.

Or use 4 wire BX.
You can not run separate wires. All the wires for a circuit must be contained in the same multi conductor cable. 12-106(1)
 

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I disagree. Those rules and exceptions are not meant to be used when running multi-wire cables, they are for single conductor. The CEC also has similar codes for when doing that.
@Dennis Alwon, what is your interpretation of these NEC articles? Can a circuit be split up into different multi wire cables for three way switching and are the NEC articles posted allowing it?
Yes, the nec does allow this install as long as it is nm cable. I have tried to get it changed but the nec panel does not care about electromagnetic field's.

Of course the easiest install is using 3 wire cable between the switches and then feed one 3 way and switch leg from the other
 

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Yes, the nec does allow this install as long as it is nm cable. I have tried to get it changed but the nec panel does not care about electromagnetic field's.

Of course the easiest install is using 3 wire cable between the switches and then feed one 3 way and switch leg from the other
I still disagree. The exemptions and codes from the NEC posted are clearly for single conductor cables.

If not, does that mean you have to cut the metal between the holes where the wire enters in the switch box as per 300.20(b) ? Seriously? This is an actual practice done in residential? Seems silly as that is really only required for currents over 200 amps which is why the rule is meant for single conductors, not nm cable.
 

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I still disagree. The exemptions and codes from the NEC posted are clearly for single conductor cables.

If not, does that mean you have to cut the metal between the holes where the wire enters in the switch box as per 300.20(b) ? Seriously? This is an actual practice done in residential? Seems silly as that is really only required for currents over 200 amps which is why the rule is meant for single conductors, not nm cable.
We use plastic boxes.
 

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I still disagree. The exemptions and codes from the NEC posted are clearly for single conductor cables.

If not, does that mean you have to cut the metal between the holes where the wire enters in the switch box as per 300.20(b) ? Seriously? This is an actual practice done in residential? Seems silly as that is really only required for currents over 200 amps which is why the rule is meant for single conductors, not nm cable.
The only reason the code allows it is so that existing installs are left alone. Some inspectors love to see a new code and demand that old stuff be ripped out, so I think this was put in to prevent that.

But no real electrician would do it.
 

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We use plastic boxes.
We can’t even use plastic straws!!!

:vs_laugh:

Our code does not allow it regardless of type of box. It just seems wrong to me as this is basic stuff taught to us from first year.
 

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Estwing magic
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Discussion Starter #37
Here’s what I was really asking with my dumb question:

It’s Saturday and I don’t want to pay HD price for 3 wire. Is it okay if I cheat? :D
 

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I still disagree. The exemptions and codes from the NEC posted are clearly for single conductor cables.

If not, does that mean you have to cut the metal between the holes where the wire enters in the switch box as per 300.20(b) ? Seriously? This is an actual practice done in residential? Seems silly as that is really only required for currents over 200 amps which is why the rule is meant for single conductors, not nm cable.
Yes, you would if you used metal boxes. Very rarely do we encounter this...

You can disagree but you would be wrong as this was brought up at a large code meeting and it was stated as a compliant install. It used to be done alot years ago but not so much anymore.
 
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We can’t even use plastic straws!!!

:vs_laugh:

Our code does not allow it regardless of type of box. It just seems wrong to me as this is basic stuff taught to us from first year.
I agree it does seem wrong and I will never do it however it is compliant.
 
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What I wanna know is why would anybody wanna put in a proposal to reduce a possible method of wiring that might come in super handy one day when you are in a pinch someplace? Just because it isn't used nowadays? Afraid of radio waves while bathing in them all day long from your iPhone and wireless routers? Because real electricians use 14-3? ( and here I hear all the time real electricians don't run nm cable at all.......). So why would anybody submit a proposal to have the practice removed from the Code? Why?





Bragging rights at Mikeholt.com is why..................
 
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