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I see a lot of RGB LED light strips being sold on sites like Amazon etc. The lights appear to be of decent quality, run off of 12V but do need up to 5-6 Amps to power. This is a lot of current, so I'm wondering if they are safe to use under my bed. Two concerns that I have is the possibility of an electrical shock and the strip/module catching fire and lighting me up in my sleep. How can I avoid these risks in my project?

This is the LED light strip/controller/power supply I'm interested in:

enter image description here

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Typically I'd ignore heat concerns with LEDs, but 12V * 5A = 60W. At those levels, I wouldn't want to have it in a confined space. –  BMitch Jun 5 '12 at 2:03
    
Most LED light strings have a transformer (power brick). That's where the heat will be generated--not from the LEDs themselves. –  DA01 Jun 5 '12 at 3:40
    
What we use as a display at work stays on 24/7 and you can touch the lamps anytime and the heat is not noticeable. –  lqlarry Jun 5 '12 at 3:54
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get creative. Build feet for it. Mount it to the bed. Etc. –  DA01 Jun 5 '12 at 13:57
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@DA01: NOT TRUE that the 60 watts will be heat generated at the transformer. If the LEDs require 12V x 5A, then they're going to get it, and emit the bulk of it as heat. The transformer may well get hot, but that's because of additional losses trying to supply that 60 watts of DC power. Assuming the bare LEDs have 20% luminous efficiency (very high) and DC transformer has 80% efficiency, you would expect 15 watts of heat from the transformer and 48 watts of heat from the LEDs themselves. Total power consumption will be 75 watts, 63 watts of which is lost as heat. –  Henry Jackson May 11 '13 at 17:58
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3 Answers 3

up vote 7 down vote accepted

You won't be able to shock yourself with 12v, but you can shock yourself with whatever power supply you find that'll do 5A at 12v. Assuming you'll only use one strip at 6a just grab a laptop power supply (I'd recommend this one: http://www.newegg.com/Product/Product.aspx?Item=N82E16812203037) - that way you really don't need to worry about whatever engineering decisions went into building that laptop power supply.

If you cleanly splice the wires, you won't have any issues. Solder them correctly, twisting them to have a mechanical connection and soldering to have an electrical connection.. then heat shrink it.

The LEDs will not give off enough heat to catch on fire or burn your bed, ever.

This project could easily be the fusion of 2 well engineered products to do something cool without any risks! Have fun!

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I'm more concerned about 6Amp flowing through the strip. AFAIK, voltage hurts but current kills. I don't have the strips right now, but I hope they have some sort of plastic covering on both sides..for protection. Btw, Nice tip about the heat shrink...I forgot about those. –  tunafish24 Jun 5 '12 at 4:06
    
Is it safe to leave laptop power supply on carpet? I'm assuming they have overload protection circuitry built-in? –  tunafish24 Jun 5 '12 at 4:08
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My laptop PSU is 130 watts and it's warm to touch at any point. In the winter, when it's cold out, I rub it on my face. So yes, they're consumer electronics, they're designed to be stable enough to be in a human environment near humans and flammable things. 60 watts at one point is a lot, you wouldn't touch a 60 watt bulb... but this is a long strip, so the wattage is dispersed and there will be more than sufficient surface area to disperse the heat. You're asking all the right questions here, glad you're taking the safe approach! –  kavisiegel Jun 5 '12 at 4:14
    
Since the product is relatively cheap, I'll just order it and see how warm it gets after running it for a while. Btw, are there any 6amp 12v fuses/circuit breakers for small projects like these? –  tunafish24 Jun 5 '12 at 5:56
    
@tunafish24, from U=R*I: 12V = 2Ω * 6A, so the LED strip has an inner resistance of 2Ω only. The human body has a significantly higher resistance (several MΩ if I remember correctly), reducing the current to a few μA if you happen to be in the current loop. In short, it's harmless. –  Simon Richter Jun 5 '12 at 8:09
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By creating a project box to store the connections you will be fine. The project box will need adequate heat dispersion capabilities because the drivers for LED's are what gives off the most heat. It is imposible for the lights to catch on fire since they give off such a low level of heat that it is unnoticeable.

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I've updated my original question with product link. I don't think a project box would be helpful with this product though. –  tunafish24 Jun 5 '12 at 4:11
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The strip that you are looking at buying is similar to the one that I have running in my room for my shelves. I keep the transformer for my lights on the floor. I have had it running for 2 years and have had no problems. –  Chris Jun 5 '12 at 12:37
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I am into club lighting and intelligent lighting in general and have done a few installs now which use led strips as the main component. While researching all of the options available to power the strips I discovered the perfect solution if you are using multiple strips...buy a CCTV power supply box. You can find them relatively cheap on Ebay. They come with the power supply already mounted inside and also include multiple outputs along with built in fuses for each one. Here is an example:
http://www.monoprice.com/products/product.asp?c_id=110&cp_id=11009&cs_id=1100902&p_id=6876&seq=1&format=2

keep in mind this solution works best when you are using smaller pieces of strip because you have to be sure not to go over the amperage of the power supply. If you really want to do it right you can mount one of these boards in the box with it:
http://celestialaudio.com/ca_dmx_32_V2_nfet/index.html

And then control all of the different zones with something like this:
http://www.nicolaudie.com/en/stick-gu2.htm

Here is a video of an LED bartop I installed which uses 5 Microsoft Kinects to make it interactive. ;)
http://www.vimeo.com/52143283

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That Kinect + LED lighting video at Vimeo is pretty cool –  tegbains Mar 30 '13 at 5:49
    
Thanks for the links...cool stuff! –  tunafish24 May 13 '13 at 3:01
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