under-the-cabinet low voltage buck lighting

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  #1  
Old 12-22-06, 07:46 AM
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under-the-cabinet low voltage buck lighting

what are some of the ways to wire these kind of lights? location for transformer???? what special type wire to run inside walls? better to run from transformer to each light...or...from light to light to light? thnaks for any help.
 
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Old 12-22-06, 02:26 PM
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The puck lights (low voltage) usually come as a kit, and the instructions will tell how many lights your transformer will handle. When I install these, I place the transformer in the cabinet over the stove, since it is the highest cabinet and generally out of sight.
 
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Old 12-22-06, 03:58 PM
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I like to put the transformer in the basement or crawl space under the kitchen , 12 volt power can be run with # 10 awg zip cord -the best wire for low voltage applications available only from a electrical suppy house
 
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Old 12-22-06, 04:10 PM
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As I understand the code, you cannot run low voltage zip cord inside the wall, it must be romex, or whatever is prescribed by your local code.
 
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Old 12-22-06, 04:31 PM
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I stand corrected
 

Last edited by william tell; 12-23-06 at 01:32 AM. Reason: bad advice
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Old 12-22-06, 04:39 PM
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There used to be a requirement that the wiring in the walls be a Chapter 3 recognized method such as non-metallic cable. The low voltage zip wire did not meet this requirement.

I am not aware of a change to this.
 

Last edited by pcboss; 12-22-06 at 04:40 PM. Reason: added 2nd paragraph
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Old 12-23-06, 01:31 AM
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ooh me bad boy -I stand corrected after research
Table 310.13 Conductor Application and Insulations.
 
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Old 12-23-06, 01:42 AM
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The big problem is that there are no listed low voltage lighting conductors that can travel through walls
 
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Old 12-23-06, 01:57 AM
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On futher research it would appear that you can use zipcord if you install in line fuses for low voltge lighting as long as the cord is sized for the ampacity
 
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Old 12-23-06, 05:17 AM
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"The big problem is that there are no listed low voltage lighting conductors that can travel through walls"

There sure is. Why would you think there isn't? Ever seen phone or CATV wire?
You need to use CL2 or CL3 rated wire.
I use cable with two insulated conductors covered in grey sheathing. The conductors have a very slight twist to them.



"On futher research it would appear that you can use zipcord if you install in line fuses for low voltge lighting as long as the cord is sized for the ampacity"

This is a new one to me. Can you provide a code reference to support this?
 
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Old 12-23-06, 07:11 PM
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Speedy, the problem is the out put wattage on the trans
and not only is my zipcord against code it would appear that cl2 or cl3 is still against code as far as you are using it, it depends on the class of trans you install


http://www.mikeholt.com
 
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Old 12-24-06, 05:27 AM
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What does the output wattage of the transformer have to do with the class of wiring with regard to using it in a wall?
Can you provide a code quote?
As long as the transformer AND wiring are Class 2 rated. ~411.4(A)(2)

You said there was NO in wall low voltage wire. I know for a fact that there is. I never said anything about "zip cord". (Although there IS CL2 rated zip cord)
 
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Old 12-24-06, 11:25 AM
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This is taken from the before mentioned forum which is an electricians only forum to debate and disscuss
the author is credited


How Safe Are “Low Voltage” Systems?

As you would agree, the world of electricity is full of misconceptions and misunderstandings. Many of the things we were told to be true simply aren’t, and many of the concepts that many people have held dear are not true either. One of these misconceptions that I’m sure we have all been told is that low voltage systems are safe from an electrical shock or fire perspective. Nothing could be farther from the truth. Just ask the owner of the building that I just returned from who had a fire from a low voltage lighting system that resulted in losses probably over $100,000, in addition to the loss of business during the business closure, the structure damage to the trusses that created the roof assembly, and the water damage from the fire suppression system.

Now, before we get too far, we need to understand this elusive term “low voltage”. What exactly does it mean? Article 411 of the NEC implies that it is between 0-30 volts. Article 720 governs certain installations up to 50 volts. Article 725 governs many “low voltage” installations, but it also contains rules that govern up to 600 volts! So which is it? Well, it really doesn’t matter that much. Fire is a function of heat, as we all know. The amount of heat that a given circuit can produce is a function of not only the voltage, but the current (amperage) as well. When you read Article 725, you will find that there are different classifications of “low voltage” circuits, depending upon the power source. A more accurate phrase for what is commonly referred to as “low voltage” is “power limited”. A power limited circuit is one that has a transformer (or other source) that limits the output voltage to a given value of both voltage and current. It is the combination of these that may or may not make a circuit safe.

When we look at the rules for class 2 wiring, we find that they are very lenient. For example, the doorbell circuit in a typical dwelling unit doesn’t need to be in a raceway or a chapter 3 cable assembly, because the amount of power that the doorbell transformer can create is very, very small. In other words, there is no way you can light a fire with it!

Low voltage lighting systems, however, are a very different thing. The fire that I discussed earlier was caused by a low voltage system that ran at 24 volts and had a 600VA transformer. This means that the “low voltage” side of the circuit had 25 amps available…more than enough to start a fire and more than enough to deliver a fatal electrical shock. So what are the rules for low voltage lighting systems? Well…they are the same as any other wiring in the building! The output wiring must be installed in a chapter 3 wiring method, such as MC cable, EMT, NM cable, et cetera. Simply installing insulated 12 AWG conductors, or installing low voltage cable is NOT code compliant. Splices are also required to be enclosed in a box, just like a 120 volt circuit. The fire that I observed was started at a free air splice, which ignited the surrounding wood of the building and put lives in danger.

Currently the state of Utah does not require low voltage and limited energy installers to have a professional license. This needs to change immediately, so the installers, inspectors and even designers can become more educated on the very real dangers associated with “low voltage” circuits that, quite simply, are not “safe”.

Ryan Jackson
2nd Vice President Utah Chapter of IAEI
 
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Old 12-24-06, 11:37 AM
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While I hold Ryan's opinon in VERY high regard, I do not agree with him on this.

411.4(A)(2) is the reason.
Also see 725.52 and 725.82
 
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Old 12-24-06, 11:40 AM
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"This means that the “low voltage” side of the circuit had 25 amps available…more than enough to start a fire and more than enough to deliver a fatal electrical shock."

True enough on it's own, but when you consider electric shock you have to consider ohms law. All the 600 VA rating means is that the transformer is capable of supplying 25 amps. That doesn't mean a typical body resistance will draw that much.
 
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Old 12-24-06, 12:18 PM
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And do you use a trans former that has seperate fuses or breakers for each run or are you using # 10 awg wire to handle the entire 25 amps .

I would be more concerned with a fire
 
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Old 12-24-06, 12:30 PM
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Speedy, according to my 2005 NEC

411.4 Locations NOT permitted. Lighting systems operating at 30 volts or less shall NOT be installed in the locations described in 411.4(A) and 411.4 (B)

is this what your code book reads ?

Article 700 is for emergency systems - I do not believe undercounter lights qualify
 
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Old 12-24-06, 12:58 PM
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Yes, but read on:

411.4 Locations Not Permitted
Lighting systems operating at 30 volts or less shall not be installed in the locations described in 411.4(A) and 411.4(B).

(A) Where concealed or extended through a building wall unless permitted in (1) or (2):
(1) Installed using any of the wiring methods specified in Chapter 3

(2) Installed using wiring supplied by a listed Class 2 power source and installed in accordance with 725.52

(B) Where installed within 3.0 m (10 ft) of pools, spas, fountains, or similar locations, unless permitted by Article 680.


And I never said Art. 700. It is 725

ARTICLE 725 Class 1, Class 2, and Class 3 Remote-Control, Signaling, and Power-Limited Circuits

See 725.52 , 725.82 , 725.54 and 725.61


You can't stop reading just because you've read what you want to see.
 
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Old 12-24-06, 01:56 PM
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still reading
 

Last edited by william tell; 12-24-06 at 02:17 PM.
  #20  
Old 12-24-06, 02:30 PM
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Art 411 in the 2005 NEC permits the use of other than "Chapter 3" wiring methods, prior editions of the NEC do not permit other than Chapter 3 wiring methods.
The restrictions for using an Art 725 type wiring method is very restrictive, and cannot be liberally used for this type of installation. Refer to Table 11(B) in Chapter 9

are you working in a town that is on the 2005 code cycle ?

The exception added in the 2005 NEC for the use of "low voltage" wire has a limit of 100 Watts. If more than 100 Watts then you must use a chapter 3 wiring method.
And Art 411 is not a low voltage wiring system. The title is lighting operating at 30 volts or less, not low voltage.

Care to discuss this amongst your peers ?

http://www.mikeholt.com/code_forum/
 
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Old 12-24-06, 02:39 PM
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My area uses the NYSRBC, not the NEC For one and two family dwellings.

If I quote the NEC it is always the latest edition. It is up to the individual to determine if it is applicable to his installation.

I know what the title of 411 is, obviously. I was not the one to use the term "Low voltage" first. Although we all can agree on the generic usage of the term in this setting.

I am very familiar with Mr. Holt's site. I have been a member for several years and receive several of his and EC&M newsletters.

Thank you.
 
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Old 12-24-06, 03:24 PM
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I am closing this thread. We have gone far beyond the original poster's question.
 
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