Cord above ceiling for Low Voltage Dimming

[jap]

Legal or not?


JAP>

 

[jumper]

Article 400 cord above a suspended drop ceiling?

 

[curt swartz]

If you are referring to 0-10 dimming controls you shouldn't be using flexible cord. You should be using an approved cable.

 

[al hildenbrand]

Legal or not?


JAP>

There is a great thead on the subject you can read by clicking here. The answer requires that the question have a little more detail. . . IMO. Near as I can see, there are four possible answers, not an either - or.

 

[jap]

If you are referring to 0-10 dimming controls you shouldn't be using flexible cord. You should be using an approved cable.

And what might that approved cable be?

I've seen it from everything from T-stat Cable to Cat 5.

JAP>

 

[GoldDigger]

Any class 2 wiring that is rated for concealed use should be acceptable as long as you do not run it in same raceway with power or Class 1 at any point.

 

[augie47]

It gets a bit complicated.
You have to make a decision as to whether your dimming circuit is going to be a Class 1 or Class 2.
The wiring method and type of cable will be dependent on that decision which will be predicted by how you terminate on each end.
This thread will shed some light on the subject.
https://forums.mikeholt.com/showthread.php?t=165467&highlight=lutron

 

[jap]

The Fixtures are already daisy chained together with MC Cable for the power , yet they did nothing as far as the 0-10v dimming (Purple and Gray) connection that was available.

I've seen others mount another 4 square (chased to the 4 square that was on top of the existing switch stubup), extend the Thhn purple and grey from that 4 square box down to the switch then take off from that 4 square with cat 5 cable to the fixture to keep the power and LV seperate yet it is not seperated from the power in the makeup enclosure on the fixture.

I'm not so sure the Cat 5 can even go into the same makep box on the fixture with the power? or should a seperate flex be daisy chained between the fixtures for the purple and grey and just pull thhn all the way from the switch to the fixtures for the dimming?


JAP>

 

[MasterTheNEC]

Et Al,

The answer to some questions will lie in the way it is asked. Since clearly the question is asking about a "cord" then I will address the question from a "cord" type position.

Section 400.8 (as you all are well aware of) will not permit a "Cord" in a structured ceiling or suspended ceiling. However, I will contend that the term "cables" as used in Article 400 is not the area of enforcement for applications of class 2 or 3 cables used within the scope of Article 725.

It is a very long and accepted practice to install Class 2 or Class 2 cables that meet the various Riser, Plenum and so on. I also encourage everyone to read the very informative- informational note after Section 725.1 as it is quite a nice little unenforceable yet enlightening note.

With that you will get my "opinion" now that is based on sitting in many of the CMP hearings over the past 2 cycles. Firstly, if the "cable" is designed as the types provided in Section 725.135 and listed per Section 725.135(A) then they are not bound by the limitations in Section 400.7, in my opinion to which you can clearly disagree if you wish as I am very closed minded to the subject just so you know.

Those that may disagree tend to say Section 400.7 does apply to the aforementioned cables yet on other issues tend to argue that the NEC is gray...you can't be rigid and remain flexible...you can quote me on that.

I also think a quick review of Table 725.154 can be very helpful in understanding the differences. The intent of Article 400 for Flexible Cord and Cables is primarily for building and/or power applications and the need for Article 725 for use with Class 2 and 3 circuits as expressed in the 0-10V lighting control type systems provides added assurance to the low smoke and exposure risks that are not afforded the various cables found under the purview of Article 400.

You can agree to disagree but you would need to speak with CMP. The application of Data and Signal Cables that are listed for the environment have been successfully used in those "suspended and dropped ceiling" locations for decades.

Just my thoughts on the subject. FYI- Or make it simple...use our Type MC-LED (PCS) Cable and kill two birds with one stone....(Yes Mods...Shameless Plug which you can remove at your leisure)

 

[augie47]

Et Al,
....................
Type MC-LED (PCS) Cable and kill two birds with one stone....)

Not to highjack the OPs original thread but related to it and for my clarity:
(a) Am I correct to assume if one uses the aforementioned cable, the system would be considered a Class 1 system ?
(b) If one elected to use a Class 2 dimming system, Is there a cord (or cable) listed for connection from a j box to the fixture ?
(c) Looking at 734.136(D) {'11 Code}, if there is a cable as asked in (b), can it be used on a 277 volt system in light of 725.136(D)(2) ?

 

[MasterTheNEC]

Not to highjack the OPs original thread but related to it and for my clarity:
(a) Am I correct to assume if one uses the aforementioned cable, the system would be considered a Class 1 system ?
(b) If one elected to use a Class 2 dimming system, Is there a cord (or cable) listed for connection from a j box to the fixture ?
(c) Looking at 734.136(D) {'11 Code}, if there is a cable as asked in (b), can it be used on a 277 volt system in light of 725.136(D)(2) ?

Responses -

(a) No, it is a Power and Lighting Cable with Class 2 or 3 Cables. The aspects of the Class 2 or 3 cable do not change, they are not being used as Class 1 cables.
(b) I would assume you could use the Type MC PCS cables (many other companies make them now) as long as you comply with aspects of 725.136(B)-(I).
(c) I'm sorry I don't have an Article 734 in my edition. However, I think you mean 725 so I will answer - (D)(2) provides options. If the Class 2 or 3 circuit conductor are indeed to be devoid of use as stipulated in 725.136(D) of the 2011 NEC (not reading from the 2014 at this point). This is all about within enclosures that are part of associated systems....if they are indeed class 2 or 3 and meet the specifications of (1) or (2) then that determines if separation is needed...within the associated systems of their potential exposure.

Now......please forgive me Augie47 if I am answering or reading your questions wrong.....and if I need to elaborate more or be more specific. Remember I am not the sharpest took in the shed as others will quickly remind you no doubt...but I attempted to answer the question as I interpreted it.

 

[jap]

There are a lot greater minds around than mine.
What have you all seen being used for the Low Voltage portion of the 0-10v dimming systems?

I'm sure not everyone is ordering the MC cable with the 2 conductor control cable although that would be nice, I dont see that as being something readily available except for being ordered in on large projects.

I think if I knew the lights were going to be dimmed, or had the possibility that they'd be dimmed in the future, I'd make my own flexes with the Purple and Grey having the same insulation in the flex along with the power, although I'd probably be higher than anyone else and not get the project anyway.


JAP>

 

[MasterTheNEC]

There are a lot greater minds around than mine.
What have you all seen being used for the Low Voltage portion of the 0-10v dimming systems?

I'm sure not everyone is ordering the MC cable with the 2 conductor control cable although that would be nice, I dont see that as being something readily available except for being ordered in on large projects.

I think if I knew the lights were going to be dimmed, or had the possibility that they'd be dimmed in the future, I'd make my own flexes with the Purple and Grey having the same insulation in the flex along with the power, although I'd probably be higher than anyone else and not get the project anyway.


JAP>

Well I can tell you we are selling the Type MC-PCS (MC-LED) hybrid cables very well and I think the rolls are available in the same lengths as traditional MC but I am not in sales so thats all I can comment on that. Many people who install the systems like "Lutron" tend to buy their Class 2 cable that is evaluated and rated for the specific aspect of exposure per Article 725. As for you making the "Cable" I would say that it is improbable that you could without the millions of dollars in machines we employ and the associated UL 1569 and 2556 testing that must take place to have a listed product. However, if you could then you too could exploit Section 725.136(I)(1) and/or (2) as well:thumbsup:

and FYI- I am not one of those smarter minds....ask any of the MODS! ( Just teasing...one or two like me...ok)

 

[jap]

When I'm talking about making a "Cable", I'm simply indicating that my flex from the fixture to the j-box would be a 1/2" aluminum flex with a switchleg, neutral, ground, purple and grey, more than likely thhn so I wouldnt have to use a Low Voltage cable at all.

The (2) dimming conductors from the wall switch all the way to the fixture would all be run in the same conduit.


JAP>

 

[MasterTheNEC]

When I'm talking about making a "Cable", I'm simply indicating that my flex from the fixture to the j-box would be a 1/2" aluminum flex with a switchleg, neutral, ground, purple and grey, more than likely thhn so I wouldnt have to use a Low Voltage cable at all.

The (2) dimming conductors from the wall switch all the way to the fixture would all be run in the same conduit.


JAP>

If those "Purple and Grey" are being used as 0-10 V, low voltage cables then that would be a problem since you would not be in compliance with 725.136(I)(1) or (2). However if the system you are using allows for the reclassifying of Class 2 or 3 conductors to Class 1 conductors and the dimming system you are connection to permits that reclassification aspect of 725.130(A) Ex. No 2 then have at it.

If you are speaking of simple local dimmers at the system voltage (120V) as the power conductors and then you are fine and not needing any thing within Article 725 for your traditional dimmer applications.

 

[augie47]

I apologize but this is one of those areas here I'm slow to comprehend.
If one chooses to use the MC-LED cable, is the Code allowance 725.136(D) and if so, are you limited to 150 vtg circuits due to the wording of 725.13(D)(2) ?
Is there a cable or cord (non MC type) that can be used from a j box to a fixture that provides the same separation as the MC-LED cable ?

 

[MasterTheNEC]

I apologize but this is one of those areas here I'm slow to comprehend.
If one chooses to use the MC-LED cable, is the Code allowance 725.136(D) and if so, are you limited to 150 vtg circuits due to the wording of 725.13(D)(2) ?
Is there a cable or cord (non MC type) that can be used from a j box to a fixture that provides the same separation as the MC-LED cable ?

Not slow....just methodical..:angel:

Firstly, the intent of a product like MC-PCS (we call it MC-LED) is under NEC 725.136(I)(1) per the UL CRD that was submitted, accepted and ratified for inclusion into UL 1569 at the version 5 printing. The aspect of 725.136(D) was never a consideration for the products evolution to be honest with you. It is my belief that item (D) is more concerned with conductor co-mingling within the enclosure and not about the cable or raceway supplying it.

(D) Associated Systems Within Enclosures. Class 2 and Class 3 circuit conductors in compartments, enclosures, device boxes, outlet boxes, or similar fittings shall be permitted to be installed with electric light, power, Class 1, non– power-limited fire alarm, and medium-power network powered broadband communications circuits where they are introduced solely to connect the equipment connected to Class 2 and Class 3 circuits, and where (1) or (2) applies:

My product will technically STOP at the gate..........(Connector rather)

In your last part of the question "Is there a cable or cord (non MC type) that can be used from a j box to a fixture that provides the same separation as the MC-LED cable ?", if you are talking about in accordance with 725.136(D) then yes and they are listed in that section. However, if you are talking about meeting 725.136(I) with something other than Type MC cable and the new PCS component aspect then yes...look at option (1)...


(1) Either (a) all of the electric light, power, Class 1, non–
power-limited fire alarm and medium-power networkpowered
broadband communications circuit conductors
or (b) all of the Class 2 and Class 3 circuit conductors
are in a raceway or in metal-sheathed, metal-clad, non–
metallic-sheathed, or Type UF cables.

Like I have said many times......this new MC-PCS is simply one way to skin the cat......725.136(I)(1) and (2) have been around long before this cable was conceived.

 

[don_resqcapt19]

If those "Purple and Grey" are being used as 0-10 V, low voltage cables then that would be a problem since you would not be in compliance with 725.136(I)(1) or (2). However if the system you are using allows for the reclassifying of Class 2 or 3 conductors to Class 1 conductors and the dimming system you are connection to permits that reclassification aspect of 725.130(A) Ex. No 2 then have at it.
...

Some of the dimming ballasts say that the dimming circuit (purple and grey wires) can be wired as either a Class 1 or a Class 2 circuit. The lets the installer do most anything he wants to and there is no need to use the reclassification exception.

 

[MasterTheNEC]

Some of the dimming ballasts say that the dimming circuit (purple and grey wires) can be wired as either a Class 1 or a Class 2 circuit. The lets the installer do most anything he wants to and there is no need to use the reclassification exception.

Yep...mentioned that in a previous post as well. However, we need to understand the term "some" as you stated. Not all permit this and if that is the case that OPTION is gone. reclassify a companies equipment and use something other than what they intended and you have made a costly mistake if a warranty claim is needed down the road on the equipment that can be upwards of $15,000 or more.

 

[don_resqcapt19]

Yep...mentioned that in a previous post as well.

I missed where you said that.

However, we need to understand the term "some" as you stated. Not all permit this and if that is the case that OPTION is gone. reclassify a companies equipment and use something other than what they intended and you have made a costly mistake if a warranty claim is needed down the road on the equipment that can be upwards of $15,000 or more.

You need to know what you are doing if you are doing electrical work. If you don't you really shouldn't be doing it.