Code quest

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SiddMartin

Senior Member
Location
PA
Off the cuff, I'm pretty sure there is a code that says you have to keep the ungrounded and grounded in the same cable. Am I wrong in this? Is there an exception for a switch loop?

I was asked to run 2 wire between recepts, and ofcourse they would like the recepts switched now and want to know if I could just run another 2 wire and use 1 wire for the switched recept and not use the other wire. I dont believe I can, and would rather just rip out the 14/2 and put in 14/3 as a better install.

thanks!
 

480sparky

Senior Member
Location
Iowegia
how bout a clip of 300.3(B) ...........:roll:
(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 (B)(4).

I think it answers both your questions.

You could either pull the 14/2 out and replace it with 14/3, or run another 14/2 and split both the grounded and ungrounded sides of the receps.
 
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SiddMartin

Senior Member
Location
PA
(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 (B)(4).

I think it answers both your questions.

You could either pull the 14/2 out and replace it with 14/3, or run another 14/2 and split both the grounded and ungrounded sides of the receps.
To run the 14/2 then I would have to carry the neutral with it.... I see what you're saying. Isn't there an exception for a switch loop? How is that allowed? Is it because there isn't a neutal being used at the switch?
 

480sparky

Senior Member
Location
Iowegia
To run the 14/2 then I would have to carry the neutral with it.... I see what you're saying..........
Use one 14/2 to feed one receptacle, and the other 14/2 to feed the other. Split both sides of the duplex (break the tabs on both sides between the terminals).


......... Isn't there an exception for a switch loop? How is that allowed? Is it because there isn't a neutal being used at the switch?
"and, where used, the grounded conductor...."

Switches don't use the grounded, so you don't need it there.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
We are talking about an NM installation so we need to read more of the section that has been cited.
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).
As long as you bring the cables into any ferrous box using a single connector, you are in compliance with the code rules.
 

SiddMartin

Senior Member
Location
PA
We are talking about an NM installation so we need to read more of the section that has been cited.

As long as you bring the cables into any ferrous box using a single connector, you are in compliance with the code rules.
Are you dis-agreeing w/ 480 or agreeing?
 

iMuse97

Senior Member
Location
Chicagoland
We are talking about an NM installation so we need to read more of the section that has been cited.

As long as you bring the cables into any ferrous box using a single connector, you are in compliance with the code rules.
a ferrous box is an iron-based metal that has magnetic properties such that a voltage could be induced in it. If both the cables enter such a box through the same KO with the same connector, you cannot induce any voltage in the box, and you are OK.
 

SiddMartin

Senior Member
Location
PA
a ferrous box is an iron-based metal that has magnetic properties such that a voltage could be induced in it. If both the cables enter such a box through the same KO with the same connector, you cannot induce any voltage in the box, and you are OK.
I am using plastic nail-on, so I would not be able to do this. thanks for the info
 

iMuse97

Senior Member
Location
Chicagoland
I am using plastic nail-on, so I would not be able to do this. thanks for the info
then you would not have any problem with your install in this regard, and could do the additional 14/2 or tear-out and do the 14/3. Have a good day; I'd do the 14/3, just b/c its how I think it should be.:smile:
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
I think he's saying you can run another 14/2 and utilize just one conductor in it, as long and the boxes are plastic and both cables enter the box through the same KO.
That is almost what I am saying. If the box is non-ferrous, then it doesn't matter how you bring the cables into the box. If it is ferrous, then they must enter via a single connector, or you can use two connectors provided that the connectors are non-ferrous and you cut a slot in the box between the two KOs.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
I'd do the 14/3, just b/c its how I think it should be.:smile:
I agree. I like my changes to look original. Plus, box-fill would be a pain with four cables per box.

Added: If we're talking about switching one box, then run a 2-wire switch loop from that box to the switch.
 
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