12V power through the wall

Thread Starter

BobTPH

Joined Jun 5, 2013
3,308
Does anyone know if U.S. electrical codes address 12V power in the walls? I am doing a remodel, making a large 32x26 ft family room and I want to light it with lots of WS2815 12V addressable LED strips.

I would like to have two 12V 30A supplies in a cabinet and run the wiring to 12 spots on the ceiling, or high on the walls. I would not have permanently installed lighting, just outlets much like the normal 120V ones, but, obviously, with a different connector.

Bob
 

MaxHeadRoom

Joined Jul 18, 2013
23,091
Usually the electrical code does not really cover below 60v.
Powered garden lights etc for e.g.
As long as service powered installations have isolation, transformer etc.
 

Thread Starter

BobTPH

Joined Jun 5, 2013
3,308
Thanks Max.

The electrician actually suggested this to me, so, I guess it is allowed. He also suggested I use 12V when I told him the strips were 5V, and, sure enough, there are 12V ones now, which makes the wiring cheaper and easier.

My worry is that the inspector will want to consider my DIY controllers and strip installation subject to inspection as installed lighting. So, my plan is to have it wired to wall connectors, with the lighting to be something you pkug in, like a lamp, and not installed lighting.

Of course the other alternative is to just wire 120V outlets at each point, but then I have large ugly boxes where they can’t be hidden.

Suggestions?

Bob
 
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click_here

Joined Sep 22, 2020
177
I can only say from my experience in Australia, but there are no codes here for low power cables.

I ran CAT/5 and RG6u cables throughout my house when I was getting major renovations done and everything passed inspection.

You'll need to keep it neat - The easiest way is to copy how the existing cabling has already been done. (Using cable clips, run along beams, neat small centred holes through beams when going through a frame)

In my case I wanted to seporate the data cable from the mains cables to minimise hum, but I don't think that it applies to what you are doing.

For the wire, I'd suggest to use automotive cable - Take note of how much current is needed, and making sure that it is capable

Make sure that the connector type isn't something that you already use - Follow the rule that if it can be pluged in incorrectly it will be.

If you currently don't have any connector types in mind, a standard 12V connector for equipment is 4pin XLR (1=GND, 2/3 n/c, 4=12V) - Power always goes out of the Female connector, because the male is prone to shorting.

If you are not confident, I suggest that you ask your electrician for guidance :)
 

SamR

Joined Mar 19, 2019
3,402
Irregardless of voltage, any residential duty wires insulation class should be suitable for the ampacity it is rated for. Either a "Romex" cable or THHN/THWN individual wires in conduit rated for 30A and no greater than the allowable conduit fill %. I would suggest contacting the local electrical inspection authority to get their take on it.
 

Thread Starter

BobTPH

Joined Jun 5, 2013
3,308
Thanks, guys, all good info. Doing a search I find that automotive cigarette lighter type sockets are available in wall plates, so I think that is what I will use. Rated at 10 A, which is perfect, since I need 7.5. I am going to have the electrician do it, since he is doing the 120, and he suggested it. That nakes it easier to pass inspection.

Bob
 

SamR

Joined Mar 19, 2019
3,402
An automotive cigar lighter socket is rated for 12V. Not sure that I understand you but using one on 120V raises some red flags especially when someone plugs a 12V device into it!
 

click_here

Joined Sep 22, 2020
177
An automotive cigar lighter socket is rated for 12V. Not sure that I understand you but using one on 120V raises some red flags especially when someone plugs a 12V device into it!
I believe that it was for 12V, not 120V

Just out of curiousity, what wall socket did you settle on?
 
It kinda does, as Class 2 wiring, but you have to limited to 100 W. https://www.ecmweb.com/national-ele...lassifying-and-using-class-1-2-and-3-circuits

Otherwise, you basically have to use conduit of some sort.

When I did a safety shutdown system, I used something like this: http://www.alarmsaf.com/ps12404.html, but it was single voltage and PTC protected and 24V. Their datasheets seem to be lacking right now.

You can get them UL listed.

I had strobes that, I think, required 1 circuit each. There were all sorts of options. I had like 16 circuits.
There are all sorts of options when used with things like access control systems, door strikes and a Fire Alarm Panel.

Some of the strobes would shut down because they needed a large start-up current.

The wiring was teflon insulated fire alarm cable. You might have to use at least plenum rated cable.
 

MrChips

Joined Oct 2, 2009
23,515
For the same power delivered to the load, 12V system requires 10 times more current than 120V system.
Since power increases as the square of the current, power dissipated is 100 times more for the same wiring resistance.
Conversely, your wire needs to have resistance that is 100 times lower for the same power loss.

This is the reason why power transmission systems use HV.
HVDC systems go as high as 500kV- 1000kV.
 

DickCappels

Joined Aug 21, 2008
7,424
In California in the 1980's during inspection of swimming pool construction the inspector noticed my 24V low voltage lighting system and asked about it. As soon as I assured hit it was for 24V only he lost interest. Thinking back he should have been interested in whether it was properly grounded. Oh, well...
 

Ian0

Joined Aug 7, 2020
2,189
In California in the 1980's during inspection of swimming pool construction the inspector noticed my 24V low voltage lighting system and asked about it. As soon as I assured hit it was for 24V only he lost interest. Thinking back he should have been interested in whether it was properly grounded. Oh, well...
But over here, it must not be grounded:- Separated Extra Low Voltage for swimming pools, transformer isolated with neither side of the secondary earthed.
 

anniel747

Joined Oct 18, 2020
1,034
I can only say from my experience in Australia, but there are no codes here for low power cables.

I ran CAT/5 and RG6u cables throughout my house when I was getting major renovations done and everything passed inspection.

You'll need to keep it neat - The easiest way is to copy how the existing cabling has already been done. (Using cable clips, run along beams, neat small centred holes through beams when going through a frame)

In my case I wanted to seporate the data cable from the mains cables to minimise hum, but I don't think that it applies to what you are doing.

For the wire, I'd suggest to use automotive cable - Take note of how much current is needed, and making sure that it is capable

Make sure that the connector type isn't something that you already use - Follow the rule that if it can be pluged in incorrectly it will be.

If you currently don't have any connector types in mind, a standard 12V connector for equipment is 4pin XLR (1=GND, 2/3 n/c, 4=12V) - Power always goes out of the Female connector, because the male is prone to shorting.

If you are not confident, I suggest that you ask your electrician for guidance :)
With automotive cabling be careful about CCAW.
 

Thread Starter

BobTPH

Joined Jun 5, 2013
3,308
For the same power delivered to the load, 12V system requires 10 times more current than 120V system.
I am well aware of that. The trade off is having 8 12V supplies that I cannot easily hide vs one or two hidden in a cabinet. Aesthetics vs efficiency.

I wonder if I can hide a 12V 7.5A supply behind a standard wall plate? That would be the best of both worlds.

Bob
 
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