0-10 volt dimmable LED troffer control wiring

[DrSparks]

I’m installing 0-10v dimmable LEDs and I have a couple questions about he control wiring:

1. I’m using class 2 CL thermostat wire (18-2) for the DC signal. From how I interpret the chapter on power limited wiring is that it’s ok for this wire to enter the junction box on the light fixture through a separate knockout. Anyone care to refute?

2. There seems to be no way to turn the fixture completely off using a DC signal. 0 volts ( or no signal) is full brightness and 10 volts is full brightness. 1-10 volts is bright somewhat proportional to voltage but there’s a plateau where no more dimming is possible at about 2 volts. I discovered by accident that removing the voltage signal and shorting the input terminals in the fixture causes the light to turn off. I tested one off to the side for a few days and it seemed to cause no harm to the electronics. I was wondering if anyone knew of this was by design and meant to operate this way. I could easily put a relay in the control box that disconnects the signal voltage and shorts the control circuit for off operation. The documentation on these fixtures is sparse.

Thanks!


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[n1ist]

Shorting the purple and grey leads will dim to the lowest light level - this may be off or may be just dim. Open is full on. On the fancier drivers, this can be programmed (whether they dim to off, and what the low and high level points are). Shorting the leads should not cause any damage as that's an allowable state.

/mike

 

[DrSparks]

Thanks. It makes sense that that would be by design. I’m new to this technology but I’m liking it.


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[Mustwin351]

Are you just putting the class 2 wire through the knockout on the j-box? Or is there a connector for low voltage wiring?

 

[lordofthisworld]

I’m installing 0-10v dimmable LEDs and I have a couple questions about he control wiring:

1. I’m using class 2 CL thermostat wire (18-2) for the DC signal. From how I interpret the chapter on power limited wiring is that it’s ok for this wire to enter the junction box on the light fixture through a separate knockout. Anyone care to refute?

2. There seems to be no way to turn the fixture completely off using a DC signal. 0 volts ( or no signal) is full brightness and 10 volts is full brightness. 1-10 volts is bright somewhat proportional to voltage but there’s a plateau where no more dimming is possible at about 2 volts. I discovered by accident that removing the voltage signal and shorting the input terminals in the fixture causes the light to turn off. I tested one off to the side for a few days and it seemed to cause no harm to the electronics. I was wondering if anyone knew of this was by design and meant to operate this way. I could easily put a relay in the control box that disconnects the signal voltage and shorts the control circuit for off operation. The documentation on these fixtures is sparse.

Thanks!


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Why don’t you just jump the lights out in Luminary cable

 

[MiElectrician]

The thermostat wire must be rated for whatever the line voltage is. It isn't written on it, you have to look it up, and maybe print out the page for the inspector. Also mcled could be easier if they aren't already wired.

 

[hbiss]

The thermostat wire must be rated for whatever the line voltage is. It isn't written on it, you have to look it up, and maybe print out the page for the inspector.

There is a reason it's not printed on the jacket, you're not supposed to know that information so you can use it for anything. All you need to know is the wire is listed as CL2 or CL3 and if you use it with a CL2 or CL3 power source you will be fine.

No inspector should care about a spec sheet, only what is printed on the jacket.

Of course, if you are using the wire in a non-NEC application- then you can use the spec sheet information as you see fit.

-Hal

 

[Fulthrotl]

1. I’m using class 2 CL thermostat wire (18-2) for the DC signal. From how I interpret the chapter on power limited wiring is that it’s ok for this wire to enter the junction box on the light fixture through a separate knockout. Anyone care to refute?

most inspectors are good with it.

god help you if you get the guy in downtown LA who doesn't
like that. he won't sign your job off. nope. nada.

you'll redo it.

ask your inspector, not us.

you can also use MC with the control wires in it. perfectly compliant.

your controls need to shut power off to the fixture when it's "off"

there are 5% fixtures, and 1% fixtures, and sometimes it's hard to tell
that there is light coming from a 1% fixture, but you want off to be off.

 

[DrSparks]

Are you just putting the class 2 wire through the knockout on the j-box? Or is there a connector for low voltage wiring?

I used a snap-in plastic romex connector. Same as what HVAC guys use for control wire.


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[DrSparks]

Why don’t you just jump the lights out in Luminary cable

I’m not sure what this means.


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[DrSparks]

The thermostat wire must be rated for whatever the line voltage is. It isn't written on it, you have to look it up, and maybe print out the page for the inspector. Also mcled could be easier if they aren't already wired.

I believe it’s 300 volts. Pretty standard.


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[DrSparks]

There is a reason it's not printed on the jacket, you're not supposed to know that information so you can use it for anything. All you need to know is the wire is listed as CL2 or CL3 and if you use it with a CL2 or CL3 power source you will be fine.

No inspector should care about a spec sheet, only what is printed on the jacket.

Of course, if you are using the wire in a non-NEC application- then you can use the spec sheet information as you see fit.

-Hal

I’m pretty sure it was on the jacket: 300 volts


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[DrSparks]

0-10 volt dimmable LED troffer control wiring

most inspectors are good with it.

god help you if you get the guy in downtown LA who doesn't
like that. he won't sign your job off. nope. nada.

you'll redo it.

ask your inspector, not us.

you can also use MC with the control wires in it. perfectly compliant.

your controls need to shut power off to the fixture when it's "off"

there are 5% fixtures, and 1% fixtures, and sometimes it's hard to tell
that there is light coming from a 1% fixture, but you want off to be off.

It’s a very customized retrofit situation. I’m aware of the MC w/ 16 or 18 awg control wires but this would not do me any good. The lights are controlled from a central MCU which is controlled by a building automation system. The power comes from several original lighting circuits on which the 3 and 4 way switches have been bypassed and blanked off. The control wire runs in a loop throughout the building and controls all the common area lighting.

The lights are pitch black when the control wires are shorted. Is there anything in the code requiring the power to be disconnected when it’s automated by a computer?


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[DrSparks]

0-10 volt dimmable LED troffer control wiring

you need to know is the wire is listed as CL2 or CL3 and if you use it with a CL2 or CL3 power source you will be fine.

The control terminals are opto -isolated and a grounded metal barrier. Definitely CL2


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[n1ist]

Some drivers turn off at 0v. Others output a low level light (1% or a programmable value). If shorting the control wires does not turn off the light, you need to open the AC feed to the driver to turn them off.

This controller, for example, provides the 0-10v control on the purple/grey wires and the switched line on the AC side (red wire)

 

[hbiss]

I’m pretty sure it was on the jacket: 300 volts...
...The control terminals are opto -isolated and a grounded metal barrier. Definitely CL2

You assume a lot! The rule is that if it doesn't actually say CL2 it's Class 1. I've never seen thermostat wire marked with a voltage for the reason I gave above.

-Hal