Replacing Incandescent with LED

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Old 07-06-16, 07:34 AM
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Replacing Incandescent with LED

Hi, need some help to make sure this will work. I am replacing 15 incandescent light fixtures with LED fixtures. This is a fraternity house, I have already checked with the City & they will allow me to wire these as long as it is only replacing existing fixtures.
Current Set-up - 3 circuits on 3 separate switches in a 3 gang box, with each switch running to 5 fixtures in a line. All wiring is in conduit, near each fixture location is a box where flexible conduit is ran to the fixture. This is all above a drop ceiling.

I expected to simply disconnect the existing fixture & wire in the new in the same locations with no or minimal disruptions to that circuit line. However they have decided to use the following LEC fixture & I have some questions specifically related to the switch to LED from incandescent.

Here is the purchased fixture - https://www.lowes.com/pd/Metalux-GR-...75-in/50392294


1. Can these fixtures be just dropped in place & wired directly to the house current?
2. Do we need to purchase a driver for these? If so, then I guess I would wire it at the 1st fixture in the line (series), then all others after it. Under this arrangement I would intend to use the existing 14ga wire in place to run all subsequent fixtures, basically just like it is now. Will that work?
3. One of the desires is to be able to dim each circuit, would a standard wall dimmer be applicable in the switch box for these (LED) fixtures?

While I have done a fair amount of electrical work as a non-pro, I have minimal experience with LED lighting. However I know it is a little different than standard, non LED lighting.

Your help is greatly appreciated. Mike
 
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Old 07-06-16, 08:02 AM
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The product information says including driver. It does not specify if they are dimmable.
 
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Old 07-06-16, 08:22 AM
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The lights are hardwired.
I checked out the manufacturer's website and here's a few quotes from the tech sheets:

Dimming: The GR LED is equipped standard with a 0-10V continuous dimming driver that works with any standard 0-10V control/dimmer.

Drivers: Long-Life LED system coupled with electrical driver to deliver optimal performance. LEDís available in 3500k or 4000k with typical CRI 85.
 
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Old 07-06-16, 08:44 AM
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The dimmer would need to be compatible with LED lighting.
 
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Old 07-06-16, 08:56 AM
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with a 0-10V continuous dimming driver that works with any standard 0-10V control/dimmer.
Thanks boss. I wouldn't call a 0-10V dimmer "standard". Maybe call it standard in that class of electronic dimmers.

A "standard" dimmer won't work, like the old rotary dimmers.
 
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Old 07-06-16, 09:22 AM
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In order to dim them, 0-10 volt dimmers would need to be installed and separate wires run to the fixtures to provide the dimming control voltage.

If dimming is required, you'd be better off trying to find line voltage dimmable lights, otherwise you will have a lot more wiring to do.
 
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Old 07-06-16, 10:23 AM
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Thanks guys for all of the quick responses.

After more leaning on my part, I believe these fixtures are wired in parallel as the main conduit run goes the entire length of the run & then a junction box is placed to separate out a line for each fixture. The main conduit line on each circuit ends at the last fixture. Does that change how this might be done? Its been a couple weeks since I have investigated the existing wiring and will not be able to go there for another week or so as I am not local to it.

Can someone elaborate more on the dimmer issue given the existing arrangement I have outlined above?

Also I just want to be sure that these fixtures will handle incoming voltage at the house line level?

Again thanks for your continued help & advice its greatly appreciated. Mike
 
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Old 07-06-16, 11:12 AM
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Parallel wiring is used. Series wiring would result in something like the old Christmas lights where if a bulb burned out the string would go out.

They are shown as being good for 120 to 277 volts.
 
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Old 07-06-16, 11:28 AM
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Not a pro on the electrical side but my concern would be ease of service. I know the LEDs are supposed to last a long time and guaranteed for maybe 5 years, but what do you is it fails in 6 years or even 3 if no one knows where to chase the warranty. I prefer a standard bulb fixture for now as bulbs of some sort will be available for many years and any TDH (Tom Dick or Harry) can hopefully figure out how to replace one. I had to buy what was available at the time for an outside flood and it had a wired in LED panel. When I asked where I would be able to get a replacement somewhere down the road they had NO IDEA. I bought and installed it, worked great and now the house is sold so will never know.

If this frat house is going to have your number you might end up wishing you used a different fixture. Just my opinion.

Bud
 
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Old 07-06-16, 11:40 AM
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You would disconnect the flex from the old fixture and attach it to the new, make the wiring connections with wires nuts or push in connectors. You have a switched connection to each fixture now, it really doesn't matter exactly how the wires are routed in the conduits. If the fixtures are daisy chained, meaning power comes into one fixture, run from there to the next to the next and so on, you will have two sets of wires coming to each fixture, power in and power out (except the last in each line, where there will be only power in). Just maintain the same scheme with the new fixtures.

Where the trouble comes in is the dimming. Unfortunately, the data sheet for these fixtures is lacking a lot of detail, and the catalog number listed by lowes, etc, doesn't match up completely with any configuration shown on the data sheet. So I am speculating a bit based on the description saying they are 0-10 volt dimmable.

Normal light dimmers simply vary the voltage applied to the fixture from 0 to 120 volts. There are LED fixtures that will work with that type of dimmer.

These fixtures use a different system, more common in industrial and commercial applications. They require a separate dimming control voltage that varies from 0 (off) to 10 volts DC (full brightness). There are wall mounted dimmers that generate this voltage. Your problem is that you will have to run new wires from the dimmers to the dimming connection on each fixture. This is separate from and in addition to the power wiring described above. You would need three of these dimmers, and would need to run new wires to each of the fixtures. They can be low voltage wires, but because it's a dropped ceiling, you would need plenum rated cable.

IIWM, I'd either tell the customer to forget about dimming (in which case all you wire is the power as described above), or I'd return those troffers and look for some that use line voltage dimming.

Good luck with your project!
 
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Old 07-06-16, 11:43 AM
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Can someone elaborate more on the dimmer issue given the existing arrangement I have outlined above?

Also I just want to be sure that these fixtures will handle incoming voltage at the house line level?
Your lights are for line voltage. Just install the wiring as if you have a simple on/off switch for each light, just as before.

The dimmers are also line voltage, same as a simple switch, but the output is different and using typical house wiring is OK and how they were designed.

I would be more concerned if the device will fit in the boxes you have.
 
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Old 07-11-16, 01:19 PM
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Post install follow-up

The install went well, all 15 fixtures working good. Its a lot brighter, uses a lot less energy and looks better. I only had to extend the wiring (replace existing flexible section with a longer one) for 2 of the 15.

Here is a new general question for you pros. Is older wire (30 - 40 year old) thicker than current wire of the same gauge?

All of the wiring in my conduit was 12 gauge. When I replaced those two sections with newer wire, again 12 gauge, the new wire is simply smaller. I also noticed how much harder / stiffer the old wire was to handle. While I have rarely worked with 10 gauge wire, that old 12 gauge wired seemed very close to the 10. And yes I did verify from the printing on the side of the old wire that it was in fact 12 gauge.

Thanks for your help earlier to my questions. Mike
 
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Old 07-11-16, 02:15 PM
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You have to look at the bare wire not the insulation covered wire. Insulation has gotten better and thinner. That makes an old unstripped wire look bigger.
 
 

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