0-10v dimming issues?

MNSparky

Senior Member
Location
Minneapolis, MN
Occupation
Electrical Contractor - 2020 NEC
I don't do a lot of 0-10v stuff so I'm trying to learn about the best wiring practices for it. Has anyone experienced what this article discusses?

.

How about running the 0-10v conductors in the same raceway as the power (purple and grey THHN in EMT with the power)?

I'm bidding on replacing all the corridor lighting in a school with new 0-10v 2x2 troffers which will involve running all new branch circuit wiring and nLight controls. Just trying to find the most efficient method to getting it done without having future interference issues. MC cable not allowed on the project.
 

tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
Wow nice find, thats your answer
Running 0-10V dimming wires in the same conduit as line voltage is not recommended.
The NEC does say that Class 1 and Class 2 wiring in the same conduit is NOT allowed, regardless of the insulation rating of the conductors. They need to be ran separately or at least separated by a continuous barrier. Running 0-10V dimming wires in the same conduit as line voltage will only be allowed if both the LED driver (or ballast) and the control module are rated for Class 1 wiring, and if the insulation requirements are met. It’s important to note that NOT all LED drivers in the market have their 0-10V dimming rated for Class 1 wiring.
Even if all the required conditions (per NEC) are met to allow running the 0-10V dimming in the same conduit as line voltage, we still do not recommend doing so in most cases. This is because we may ran into a situation where the 0-10V wiring can pick up 60Hz AC noise from the line voltage wiring, which can lead to dimming performance issues.
Check to see what your options are for class2 wiring, does that have to be in pipe? Flex ok?
That said, in a remodel I have run it in EMT with 120V circuits and reclassified as class1, we never use gray, too easy to confuse.
In new work if the fancy MC with the extra wires is not allowed we run a different pipe.
The only thing I have found to reliably not work is other brands wireless battery powered dimming / occupancy sensor 'solutions'. Easy to put in and lots of call backs on those.
 

MNSparky

Senior Member
Location
Minneapolis, MN
Occupation
Electrical Contractor - 2020 NEC
Found out more info for everyone's reading pleasure:

I found this on the MN Dept of Labor and Industry's FAQ website which answers some questions:

https://www.dli.mn.gov/sites/default/files/pdf/eli_bulletin_led.pdf

I also spoke to the inspector and his area rep, which cleared some other things up. They are allowing us to run the TC cable inside a raceway along with the switching conductors, they say the jacket on the TC cable counts as the barrier, similar to the MC with the TC cable installed. They said running THHN would be a violation as there is no barrier. They referred me to 2020 NEC 725.136 (I) for additional info. I'm just wondering if it would be a good idea or waste of money to run shielded TC cable in that same pipe....
 

mikeames

Senior Member
Location
Germantown MD
Occupation
Teacher - Master Electrician - 2017 NEC
You can use a DUO cable. I have used the NM and MC version. This example is Patient care as well.



EDIT - JUST SAW YOU CANT USE MC on your job.....
 

mikeames

Senior Member
Location
Germantown MD
Occupation
Teacher - Master Electrician - 2017 NEC
Then buy fixtures that have a class 1 rating on the control side, reclassify your control as class one and use the same raceway for both.
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
They are allowing us to run the TC cable inside a raceway along with the switching conductors, they say the jacket on the TC cable counts as the barrier, similar to the MC with the TC cable installed. They said running THHN would be a violation as there is no barrier. They referred me to 2020 NEC 725.136 (I) for additional info. I'm just wondering if it would be a good idea or waste of money to run shielded TC cable in that same pipe....
I've been saying do that since before the 2020!

Why would you want to use shielded TC???

-Hal
 

MNSparky

Senior Member
Location
Minneapolis, MN
Occupation
Electrical Contractor - 2020 NEC
I've been saying do that since before the 2020!

Why would you want to use shielded TC???

-Hal
I thought shielded may help with the possible interference issues discussed in the Acuity article I posted. I guess if Southwire isn't putting shielded in their MC and NM, perhaps it's not necessary. I have little experience with 0-10v so I don't have past experience to rely on here.
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
I've never heard of anybody having any interference issues.

What I do find interesting is this passage because there are people here who insist it's OK to "reclassify" the CL2 into Class 1 by simply crossing out the CL2 on the driver label with a sharpie and using THWN for the 0-10V. That, incidentally, would be the same as using 4 conductor MC which is prohibited.

Running 0-10V dimming wires in the same conduit as line voltage will only be allowed if both the LED driver (or ballast) and the control module are rated for Class 1 wiring, and if the insulation requirements are met. It’s important to note that NOT all LED drivers in the market have their 0-10V dimming rated for Class 1 wiring.
-Hal
 

mikeames

Senior Member
Location
Germantown MD
Occupation
Teacher - Master Electrician - 2017 NEC
I've never heard of anybody having any interference issues.

What I do find interesting is this passage because there are people here who insist it's OK to "reclassify" the CL2 into Class 1 by simply crossing out the CL2 on the driver label with a sharpie and using THWN for the 0-10V. That, incidentally, would be the same as using 4 conductor MC which is prohibited.



-Hal
I agree with the interference, But Ill also clarify that my use of the word reclassify means to use the appropriate fixture and treat the class 2 as class 1. If that is done its a complaint and safe install.

Generally speaking Class two requires less protection compared to class one. Reclassifying can be a slang way of saying "Treat it like class one". Assuming the supply side and fixture side is complaint.
 

tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
Last time I looked for reclassifying to answer a question in another thread a couple of weeks ago, I found that it no longer exists in the 2017. Take a look, maybe I'm getting whacky in my old age.

-Hal
2017 NEC said:
725.130 Wiring Methods and Materials on Load Side of the
Class 2 or Class 3 Power Source. Class 2 and Class 3 circuits
on the load side of the power source shall be permitted to be
installed using wiring methods and materials in accordance with
either 725.130(A) or (B).
(A) Class 1 Wiring Methods and Materials. Installation shall
be in accordance with 725.46.
Exception No. 1: The ampacity adjustment factors given in
310.15(B)(3)(a) shall not apply.
Exception No. 2: Class 2 and Class 3 circuits shall be permit-
ted to be reclassified and installed as Class 1 circuits if the
Class 2 and Class 3 markings required in 725.124 are elimi-
nated and the entire circuit is installed using the wiring methods
and materials in accordance with Part II, Class 1 circuits.
Informational Note: Class 2 and Class 3 circuits reclassified
and installed as Class 1 circuits are no longer Class 2 or Class 3
circuits, regardless of the continued connection to a Class 2 or
Class 3 power source.
Not any signifigant change in 2020 NEC either
 
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