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Discussion Starter · #1 ·
Hi All,

I have been looking around the web, from Reddit all the way to Mike Holt's forms and I cannot seem to get all of the information I need.

I have been working on my basement, and the last project for this phase is to replace the built in bookshelves. Well the build of the shelves is complete, just need to install them into the wall. Then I remembered I wanted lighting in the shelves. I have not installed them yet, so we can do what ever we need. I figured I would use a product I was familiar with, LED Tape lights. Specificalled 5050 12v RGB lights. (link to amazon)

Problem is, I've only used them with the wall wart. But I know and have read about others using a 120v ac to 12v dc transformer to hardwire these type of light. I also do not want to use a wall plug because I would like them to turn on/off when the sconces are turned off and on, so if I can hardwire, I can simply tie them into the circuit.

A few helpful facts:
-I need to run about 26.5ft of light
-I would like to use 12v dc, not 24v
-I would like to use RGB (multicolor) lights
-There is a light switch controlled sconce nearby so I plan on connecting into that
-I would probably be use 300 count LED strips (as per the earlier link)

SO...Here is want I am looking for:
1) What type/model of transformer can I use?
2) Can I mount that transformer in a drop ceiling on joist?
a. If yes, does it need a special housing
-If it does need a housing will that affect the heat output?
b. If no, where should I mount it
3) On the transformer 12v DC output side, what gauge and type of wire should i use to run behind the drywall to the backside of the bookshelves where it will connect to the LED strips.

Thanks for reading and feel free to ask any questions, I will respond as soon as I am able. Sorry if the question is confusing.

For reference, I have included pics of the basement with the shelves sitting in the wall. You can see I have easy access to the drop ceiling and I can take the shelves out and access the studs and wall behind them easily. You can also see the sconce I would source the power from so it can be switch controlled.

Thanks
Z
 

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The Amazon site which you referenced is not helpful in that it does not indicate the (maximum) current drawn by these LED devices.

However, the LEDNET site (http://www.ledenet.com/flex-led-strip-light/414-rgbw-led-strip.html) does indicate this as being 0.6 Amps per Metre.

Your estimated length is 26.5 Feet, which is about 8.08 Metres.
Hence you require a DC Power Supply (NOT just a Transformer) capable of supplying AT LEAST 5 Amps at 12 V DC (60 W)
(Since 8.08 * 0.6 = 4.884)


If you “hardwire” these items in any way shape or form, how will you control them?

I do suggest that you look at the LEDNET site http://www.ledenet.com/46-led-strips-controller for further information.

(However, I have NOT noted on this site any controller which will control BOTH the RGB LEDs and the White LEDs.)

As for your Questions 2, I cannot advise you on any Regulations/Code applicable in whatever part of North America you may reside, except to say that the “Output” of any “Power Supply” will be at “Extra Low Voltage” levels so the regulations which apply will be the same as those that pertain to the mounting of items such as “Door Bell” transformers and their associated “Extra Low Voltage” wiring.

As for Question 3, any “Extra Low Voltage” wiring suitable for installing 12 V wiring in “Gardens” and rated up to (or above) the 5 Amps concerned should be suitable.
 

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Discussion Starter · #3 ·
@ FrodoOne , thanks for the response. I have a few follow up comments and questions.

As for Question 1, I am glad you suggested the LEDNET controller as that is what I already have on hand and am familiar with using on regular projects using the led strips. As far as the the AC to DC and 12v power is concerned

Hence you require a DC Power Supply (NOT just a Transformer) capable of supplying AT LEAST 5 Amps at 12 V DC (60 W)
(Since 8.08 * 0.6 = 4.884)
Would a AC to DC transfomer such as (Mean well Link) do the trick to power the whole thing? If not, what do you suggest?

On questions 2, I understand why you cannot advice me specifically, but Where would I look in the NEC to get more exact guidance on this? IS there a reference anywhere else that would be beneficial for me to look? I see that you are pushing me to look at doorbell wiring rules, but I always like to have a set of rules to work around.

Other than than, I think I am good. I apprecaite any help or guidance I can get. I am decent at basic electrical, but this hits a number of odd topics so I figured I would reach out.

thanks again
 

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Would a AC to DC transfomer such as (Mean well Link) do the trick to power the whole thing? If not, what do you suggest?

On questions 2, I understand why you cannot advice me specifically, but Where would I look in the NEC to get more exact guidance on this? IS there a reference anywhere else that would be beneficial for me to look? I see that you are pushing me to look at doorbell wiring rules, but I always like to have a set of rules to work around.

Other than than, I think I am good. I apprecaite any help or guidance I can get. I am decent at basic electrical, but this hits a number of odd topics so I figured I would reach out.
A "Power Supply" such as the (Mean Well) item which you quoted seems to be ideal for your requirements. However, since it is rated at only 60 W, it should NOT be loaded with any significantly greater length of LEDs.

(If I may digress a little at this point, I am often surprised by the names which Chinese based organisations choose for their Companies and Products. While the Chinese version of these names may sit comfortably with their originators, the English translation often seems quite "incongruous" to my ears. Often, it seems like something out of a "Monty Python" sketch!

Also, by putting "USA" in the title it may make one think that the company is based in the "USA", whereas it is based in Taiwan and the products may be made there - or in mainland China.
However, they seem to be of good quality.

You should note that they follow "European practice" concerning the "Colour Codes" involved.)

I regret that I cannot help you any further with Question 2.

Since you are dealing with a 12 V supply I suggest that it is probable that you could do almost anything you like with the wiring involved. You should note that the output voltage of the Power Supply concerned is no greater than that of the battery in what is probably your automobile AND it is capable of supplying only a MUCH smaller current.

Hopefully, if I am wrong in this, someone knowledgeable with NEC regulations will "jump in" and tell us.

With "discussions" such as this, while persons who agree are unlikely to say anything, those who disagree are almost certain to offer their advice.
 

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The power supply you have chosen is UL listed (along with myriad other listings). It is not meant to be encased in an enclosure, thus the mounting ears on the ends. It needs to have natural air circulation for proper cooling.

If the unit does not have a plug molded onto the "high voltage" side cord, you may hard wire it into your current lighting circuit as you wish. The HV splice must be made in a listed enclosure using standard methods just like any other electrical device you would install in your home.

The low voltage side is a little easier to deal with. Simply google "low voltage wire" and then choose and buy the length you need. I have not checked your lighting specifications, but the 60 watt power supply shown the link above will do nicely with #18 AWG low voltage extension wire on the LV side. LV splices do not require a junction box as with power wiring. Usual splice methods employ heat shrink tubing. I solder my LV LED joints. Install a single heat shrink on each conductor, slip a larger heat shrink over one of the cables, solder each wire, then shrink all three covers. There are also crimp connectors for extension wiring if you want. Google is again your friend.

In short, mount your power supply to a joist above the drop ceiling, install proper wiring and a splice box close to it from your wall sconce for the HV, splice your extension wire onto the pair from the power supply on the LV side, and light it up.
 

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Discussion Starter · #6 ·
First, a big thanks to both FrodoOne and al_smelter


T
Your estimated length is 26.5 Feet, which is about 8.08 Metres.
Hence you require a DC Power Supply (NOT just a Transformer) capable of supplying AT LEAST 5 Amps at 12 V DC (60 W)
(Since 8.08 * 0.6 = 4.884)

Does it matter if the total length of LED strip lights does not change, but it is split into 3 strips.In other words, does this calculation still remain valid if instread of running one continuous strip at a length of 26.5ft, I run 3 strips off the same power supply, and each strip is about 2.9ft (lets call it 3ft)?

Thanks, and let me know if you need clarity

Thanks so much
 

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Does it matter if the total length of LED strip lights does not change, but it is split into 3 strips.In other words, does this calculation still remain valid if instread of running one continuous strip at a length of 26.5ft, I run 3 strips off the same power supply, and each strip is about 2.9ft (lets call it 3ft)?
It does not matter if the extra wire connecting the various light strings and the power supply is "generous" in its gauge - similar to that which is used for "garden lighting" - and not too long!
 

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Discussion Starter · #8 · (Edited)
It does not matter if the extra wire connecting the various light strings and the power supply is "generous" in its gauge - similar to that which is used for "garden lighting" - and not too long!
FrodoOne, so in the attached picture, it doesn't change the power supply requirements, if I break up the strips like this?

Thanks so much, this project is allowing me to learn a lot.

Just to confirm new diagram LED strip length should be 8.7ft
 

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