# 0-10 volt dimming wires



## DashDingo (Feb 11, 2018)

Got a situation in an existing facility where we changed out fluorescent 2x4 lay in fixtures to new LED type.
They are complaining that the new fixtures are to bright and want them dimmed.
The new fixtures are 0-10 dimming ballast.
All the existing switch legs run down a chase and into cabinets and disperse to about 10 different switch locations in the cabinets.
The cabinet/ built ins have access panels and runs about 40’ long. ( patient locations).
So rather that me replacing all the switch legs, that are run in hospital grade MC with conduit ( pita) I just want to pull and 18-2 stat wire for my 0-10 v dimming wires.
The box that the switches are in I want to nipple a handy box on and just splice some Thhn in there and run it to the dimmer switch.
Inspector said you can’t do that I’ve never seen that done before.
Is he right? I want to ask him for a code reference.



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## Dennis Alwon (May 9, 2009)

These 0-10v dimming causes more issues than one can imagine. The only issue I see is whether the stat wire is a class 2 wiring method. Most of the dimming must be done with class 2 wiring.


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## B-Nabs (Jun 4, 2014)

A lot of the time the dimmers have the line voltage and dimming wires coming right off the back in the save device box, so if you run the dimming wires in a class 1 compliant wiring method then all is good. I've used armoured fire alarm cable for this purpose a lot. Insulation rated for 300v and the armour makes it kosher as class 1 wiring.

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## B-Nabs (Jun 4, 2014)

Alternatively if you've got pipe feeding a lot of these lights and it wouldn't be too much of a PITA, you could pull unarmoured FA cable in those pipes. 

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## bostonPedro (Nov 14, 2017)

I think this being a hospital is going to make this difficult because pulling 18-2 cable wire to the lights like we do all the time in commercial probably wont be legal in a hospital BUT I am not certain about this 

Does the conduit lay out to lights make it possible to just run some 18 gage thhn for your low voltage cable in the same conduits then come out of cans with mc containing your high voltage and low voltage cables?


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## DashDingo (Feb 11, 2018)

B-Nabs said:


> A lot of the time the dimmers have the line voltage and dimming wires coming right off the back in the save device box, so if you run the dimming wires in a class 1 compliant wiring method then all is good. I've used armoured fire alarm cable for this purpose a lot. Insulation rated for 300v and the armour makes it kosher as class 1 wiring.
> 
> Sent from my SM-G975W using Tapatalk




I was wondering if he could ping me on not having the line voltage wires and dimming wires not being in the same cable assembly?


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## DashDingo (Feb 11, 2018)

Dennis Alwon said:


> These 0-10v dimming causes more issues than one can imagine. The only issue I see is whether the stat wire is a class 2 wiring method. Most of the dimming must be done with class 2 wiring.



I was wondering if he could ding me on the line voltage wires and the 0-10 v dimming wires not being in the same assembly?



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## bostonPedro (Nov 14, 2017)

DashDingo said:


> I was wondering if he could ping me on not having the line voltage wires and dimming wires not being in the same cable assembly?
> 
> 
> Sent from my iPhone using Tapatalk


Actually quite common to do that when using a Lutron lighting system but my area might be different than yours


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## splatz (May 23, 2015)

If the 0-10V dimming is not a class 1 circuit, its not too bad. You wire it using regular chapter 3 methods. By 725.48(B)(1) you can run the dimming and the power in the same raceway or cable, they are "functionally associated" but I don't think you could have anything else in there. 

If the 0-10V dimming is a class 2 circuit, that lets you go a lot looser with the wiring method - you see what people do with flying splices etc for say speakers. The problem is if you look at 725.136 you probably won't have a way to run it in the same conduit or raceway. 

Complying with 725.136 is usually actually be harder than just wiring it as a regular class 1 circuit with a regular chapter 3 method. Luckily, 725.130 spells out how to reclassify the class 2 circuit as class 1 and then you can / must wire it as a class 1 circuit.


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