12-2-2, Three Switch legs

[infinity]

Is it permissible to use 12-2-2 NM cable for three switch legs by re-identifying one of the white conductors?

 

[al hildenbrand]

Is it permissible to use 12-2-2 NM cable for three switch legs by re-identifying one of the white conductors?

I've certainly done it, and never given it a second thought. I especially like a 12/4 or a 12-2-2 to be the switched legs into a bath exhaust fan / light / heat unit, for the ease of make-up in the fan J-box.

 

[al hildenbrand]

Consider a 240 Volt 20 Amp branch circuit wired with 12/2 NMB. The branch circuit goes to a two-pole thermostat and continues on to a 240 Volt resistance electric space heater. The NMB white conductor must be re-identified when used as an energized conductor whether switched or un-switched.

I believe this is directly analguous.​

 

[Dennis Alwon]

I don't see why it wouldn't be acceptable but I agree 12/4 would be better

 

[wwhitney]

This part of 2014 200.7(C)(1) limits you somewhat:

If used for single-pole, 3-way or 4-way switch loops, the reidentified conductor with white or gray insulation or three continuous white or gray stripes shall be used only for the supply to the switch, but not as a return conductor from the switch to the outlet.

Cheers, Wayne

 

[al hildenbrand]

This part of 2014 200.7(C)(1) limits you somewhat:

Well, does it really?

Considering my situation with three single pole switches controlling an exhaust fan / light / heater where the fan J-box is fed by a 120 V 20 A Branch Circuit thru a 12/2 NMB, and a 12-2-2 NMB is installed as a Switch Loop, Wayne, are you saying that after the UnSwitched Hot is connected in the Switch Loop cable on the re-identified White, or White (or Grey) Striped, Conductor, that the language PROHIBITS the re-identification of any ADDITIONAL White, or White (or Grey) Striped, Conductors?

I read this passage from the NEC as SILENT about any additional conductors that can be re-identified.

 

[Dennis Alwon]

I agree with Whitney. The white cannot be re-identified as a return conductor only as a hot conductor. I didn't think about that in my first post. It may pass inspection but it isn't compliant

 

[wwhitney]

(2014) 200.7(C) says

The use of insulation that is white or gray or that has three continuous white or gray stripes for other than a grounded conductor for circuits of 50 volts or more shall be permitted only as in (1) and (2).

So if you don't meet one or two, you can't reidentify. And (1) does not allow reidentifying for a switch loop conductor between a switch and the outlet. [A stupid prohibition in my opinion.] (2) covers only cords. That means what you propose violates 2014 200.7(C).

Cheers, Wayne

 

[al hildenbrand]

Don't forget the Article 404 requirement for a grounded conductor at the switch location . . .

 

[al hildenbrand]

I mean, again considering my exhaust fan / light / heater scenario, just how likely is the use of a Switch Loop anyway. I like a 12/4 or a 12-2-2 for the Switched LEGS because it keeps the wire count down in the fan J-box. With the Article 404 neutral requirement, why in the world would I feed the fan, rather than the switch box? I don't need a Switch LOOP, therefor I'm not forced to use the sub part of the 200.7(C) rule.

 

[wwhitney]

I mean, again considering my exhaust fan / light / heater scenario, just how likely is the use of a Switch Loop anyway.

Well, I was responding to your original scenario, which did specify a switch loop. Given the Article 404 requirements you pointed out, the switch loop would require 12-5 or 12-2-3 or something like that which probably doesn't exist.

And with the requirement for a grounded conductor at the switch, with a switch loop the limitation in 200.7(C)(1) isn't so bad unless you have more than two white conductors in your cable. You can use one white conductor for the grounded conductor, and you can reidentify the other white conductor for the supply to the switch location.

Cheers, Wayne

 

[al hildenbrand]

Well, I was responding to your original scenario, which did specify a switch loop.

Read it again, please, Wayne. Rob asked about switched legs, and I responded about switched legs. You then introduced switch loops.

 

[jap]

I would agree with those saying it's not NEC Compliant.

You can use the white as power down, but not as a switch leg back up.

When it comes to items that require more than 2 "Switchlegs" I've found it simpler to resort to other types of wiring methods than NM.

But that's just me.

JAP>

 

[oldsparky52]

I mean, again considering my exhaust fan / light / heater scenario, just how likely is the use of a Switch Loop anyway. I like a 12/4 or a 12-2-2 for the Switched LEGS because it keeps the wire count down in the fan J-box. With the Article 404 neutral requirement, why in the world would I feed the fan, rather than the switch box? I don't need a Switch LOOP, therefor I'm not forced to use the sub part of the 200.7(C) rule.

12/4 color codes are compliant, 12-2-2 color codes are not.

 

[infinity]

Read it again, please, Wayne. Rob asked about switched legs, and I responded about switched legs. You then introduced switch loops.

Yes switch legs, 3 of them plus the neutral conductor, feed is already at the switch. Take the white/red conductor from the 12-2-2 and tape it blue. As dumb as it sounds I believe that this wouldn't be code compliant.

 

[Cow]

Which company makes 12-4 nm-b? I have not seen it, only 12-2-2.

 

[al hildenbrand]

Which company makes 12-4 nm-b? I have not seen it, only 12-2-2.

Most any cable manufacturer. The fourth conductor is blue. White, black, red and blue.

 

[al hildenbrand]

Yes switch legs, 3 of them plus the neutral conductor, feed is already at the switch. Take the white/red conductor from the 12-2-2 and tape it blue. As dumb as it sounds I believe that this wouldn't be code compliant.

Not a switch loop.

The sentence in 200.7(C), that is a PART of the rule, is self-contained, in my opinion. The last part of the "switch loop" sentence applies to the object of that one sentence, i.e., "switch loops"

If used for single-pole, 3-way or 4-way switch loops, the reidentified conductor with white or gray insulation or three continuous white or gray stripes shall be used only for the supply to the switch, but not as a return conductor from the switch to the outlet.

If this (the "switch loop" sub-rule) applied globally (which IMHO it does not) using two-wire NMB between a two pole thermostat and a 240 Volt electric space heater cannot be allowed.

 

[ActionDave]

I agree with Al.

 

[texie]

Not a switch loop.

The sentence in 200.7(C), that is a PART of the rule, is self-contained, in my opinion. The last part of the "switch loop" sentence applies to the object of that one sentence, i.e., "switch loops"



If this (the "switch loop" sub-rule) applied globally (which IMHO it does not) using two-wire NMB between a two pole thermostat and a 240 Volt electric space heater cannot be allowed.

I agree. While subtle, there is a difference between a switch loop and switch leg.