Low Voltage Wiring Question

[Gattopuin64]

I am adding several 12-V LED light fixtures, thus the wiring question. I will splice into a nearby low voltage wiring, with a run of no more than 10-12 feet. In addition low voltage switches will be added to turn the LED light fixture on/off. Best guess the power draw will be no more than 2-3 amps.

Can I use 16/2 stranded lamp wire for the 12V LED lights project? This wire is cheap and I can get it by the foot at my local Home Depot or Lowe's

Henry

[steve dunham]

Lamp cord is not listed , rated or code / UL approved for concealed or permanent wiring . Cord must be exposed along its entire length.
Cheap and safe do not usually equate.

[rbryan]

Originally Posted by steve dunham

Lamp cord is not listed , rated or code / UL approved for concealed or permanent wiring . Cord must be exposed along its entire length.
Cheap and safe do not usually equate.

Totally agree. Use regular insulated wire and do it right.

[floyd]

Originally Posted by steve dunham

Lamp cord is not listed , rated or code / UL approved for concealed or permanent wiring . Cord must be exposed along its entire length.
Cheap and safe do not usually equate.

I have no doubt that what you say is true, but we are talking about 12VDC, not 110VAC.
This is a lot more akin to automotive wiring than to house wiring.
If you buy a 16/3 extension cord in the color of your choice (I like white for this purpose) It will work great for 12V lighting with led lights.
Of course unlike lampcord it has individually insulated and color coded wires with strain relief and an outside insulator.

[tractors1]

If you check the wire used in outdoor landscape lighting it's basically lamp cord construction and runs 12VDC, and is buried underground. Don't think it has a UL approval stamp.

Same material is used to charge batteries in gate openers but with a minimum of 12 gauge on long runs; my opener is 550 ft from the transformer that charges it.

I've used it for many applications. I also don't recall seeing approval stamps on the 12V wiring in my Escape, although I could be wrong.

[floyd]

Originally Posted by tractors1

If you check the wire used in outdoor landscape lighting it's basically lamp cord construction and runs 12VDC, and is buried underground. Don't think it has a UL approval stamp.

Same material is used to charge batteries in gate openers but with a minimum of 12 gauge on long runs; my opener is 550 ft from the transformer that charges it.

I've used it for many applications. I also don't recall seeing approval stamps on the 12V wiring in my Escape, although I could be wrong.

Turns out that it appears to be (UL) listed.... I just went out to the shop and grabbed a scrap of the landscape low voltage wire and this is what it says on it...
(UL) E236055 14AWGX2C 150V 60C LOW ENERGY UNDERGROUND CIRCUIT CABLE SUNLIGHT RESISTANT FT2 ME-2 -C(UL) (LVLL 3OV)
WHEW!!
Clearly better and heavier than most household lamp cord.
I got mass quantities of the stuff at a garage sale for a buck.

Aftermarket wiring supplied by Ford is commonly marked with SAE rather than (UL) and sometimes with temperature ratings if expected to be used near hot engine components.

I also grabbed an old wiring harness from a Maytag washing machine and it has no (UL) stamp but it does have other pertinent info on each wire.

[k corbin]

If you want to know the electrical standards that apply to wiring for things such as running wires for LEDs then look up the electrical code for "low voltage". Do not try to apply all of what you know about the standards for 120 wiring in your home to everything that is done with 12v (or lower) in a travel trailer because it is not the same UL standard.

[Raspy]

You definitely don't have to follow the code for high voltage wire when wiring 12 volt LEDs. Low volt is it's own category in house wiring and is done concealed all the time with minimal insulation bell wire, or equivalent. However, if you buy a 16 or 18 gauge extension cord and use that, you'll have excellent, mechanically durable, insulated and stranded wire that has the ability to endure a lot of vibration and mechanical chafing. It would be better than lamp cord because it's better protected with more layers of insulation. And if you are worried about it, it will carry a UL listing too.

[steve dunham]

The problem with lamp cord is the type of insulation ( It rapidly deteriorates from age and heat and gets brittle ) not with the conductors . Low voltage wiring in homes is run in UL approved cabling. Many people try to run sound systems with rip cord and soon discover that it is not approved for the purpose . You need to use UL approved signal / sound wiring .
I am not saying that rip cord won't work but only that it is not code compliant and will lead to problems
I DO KNOW THE DIFFERENCE BETWEEN LOW VOLTAGE AND LINE VOLTAGE WIRING .
In my over 40 years in the trade I have NEVER installed lamp cord as a wiring method except to repair a lamp.

If you look at the front section of the NEC code book you will find what the code covers . The NEC code does NOT apply to automobiles / vehicles . It DOES apply to RV's and travel trailers wiring both line and low voltage.

[floyd]

Originally Posted by steve dunham

The problem with lamp cord is the type of insulation ( It rapidly deteriorates from age and heat and gets brittle ) not with the conductors . Low voltage wiring in homes is run in UL approved cabling. Many people try to run sound systems with rip cord and soon discover that it is not approved for the purpose . You need to use UL approved signal / sound wiring .
I am not saying that rip cord won't work but only that it is not code compliant and will lead to problems
I DO KNOW THE DIFFERENCE BETWEEN LOW VOLTAGE AND LINE VOLTAGE WIRING .
In my over 40 years in the trade I have NEVER installed lamp cord as a wiring method except to repair a lamp.

If you look at the front section of the NEC code book you will find what the code covers . The NEC code does NOT apply to automobiles / vehicles . It DOES apply to RV's and travel trailers wiring both line and low voltage.

Deferring to your expertise... please comment on the practical suitability of 16/3 extension cord as described in my earlier post #4 (individually insulated and color coded wires with strain relief and an outside insulator, not lamp cord) for this application, powering 12V LEDs.

[Franswa]

one really has to wonder however....

on the one hand, in my living room, lightcord is supposed to be perfectly fine lying there loose on carpet to power a 60W lightbuld with 110V AC running through it...(and with hanging lamps the length of run could be 10-12 feet)...

BUT in my trailer this same cord, tied up and secured, is considered inadequate to power 3-4 LEDs that consume a stupidly low amount of power???

personally I wouldn't use lampcord...but it's because there's so much wire in my trailer already that I'd be inviting confusion at a later date for me or someone else....NOT for any other considerations

I'm reminded of MacGregor Yachts....built and sold trailerable sailboats...used lampcord for all 12V wiring. The boating press berated the practice over and over and over again.....MacGregor went on to produce more boats in it's 30 year history than ANYBODY...worldwide!!! and always used lampcord...LOL

[steve dunham]

The cord on your living room lamps is exposed and you can visually inspect the cord . Flexible cords of any type are not supposed to be used in concealed locations . It has NOTHING to do with being able to carry the load , it has to do with the type of insulation .
The insulation on NM cable has been tested and designed to maintain its' integrity for a period of over 100 years .
I have seen flexible cord insulation deteriorate in less than 5 Years .
A 12 vdc arcing fault in contact with flammable materials can cause a fire just as easily as 120 VAC.
If I was going to use cord in a trailer for lights , I would use a hard usage neoprene cord such as Floyd suggested.
I have a spool of 300 volt rated , UL approved 14/2 cable with a fire resistant outer jacket . The cable contains one red and one black conductor and is approved to be installed in concealed locations and in fire rated walls.

[Gattopuin64]

Thanks y'al for the comments on the types of low voltage wire.

After reviewing the comment and not sure of the code/safety factor, my best course of action will be regular 16/2 stranded wire like the underground stuff. The cost is not the problem but buying only 15-20 feet for my small project.

Henry

[J Ron]

All LEDs that I have purchased for autos came with very small wire. LEDs are voltage devices not current, since the curren t is so low the size of the wire has much less value. Also I've had people I bought LEDs from recomend mounting the wire with super glue. This worked very well when adding a third stoplight on a VW Vanagon. If using LEDs on a 120 volt circuit I'm more cautious about wire size since more current is used in converting to 12v.

[Franswa]

one should always keep in mind that when you do some work on a trailer (or a boat) the parts will be a VERY SMALL cost compared to the time involved (not to mention the frustration of working in very tight places....you don't want yourself or ANYBODY to do this again)....

I remember doing extensive rewiring on a boat....and even though I left some lampcord wiring in place for some items...all new wiring I used was the very expensive tinned wire (the "correct" / "proper" wire in boats)

and as an added benefit maybe....when you decide to sell your pride and joy....being able to point to the totally correct and possibly overbuilt nature of your work/additions will instill confidence in a prospective buyer that might translate to a higher resale value to you

have fun...

[Raspy]

Franswa,

Excellent points.

Yes, tinned and stranded wire is the best of the best. I used a lot of it on my boat too.

There is really nothing wrong with lamp cord in many cases, but it just seems so cheesy. High quality, fine stranded wire, and preferably tinned (at least on boats) is so much nicer and confidence inspiring.

[Byron Kinnaman]

A simple answer is NO NO NO.
The trouble with it is the insulation, it sustains fire.

The correct wiring is automotive SAE approved wire (Society of Automotive Engineers).

I hope to dispel a concept that you mess with 12 volt systems because you can't get shocked. Nothing can be farther from the truth. 12volt systems are just as dangerous as 120 or 220volt cousins. The biggest problem with any electrical system is fire or potential for fire. Teflon or Cross Link insulation has sever advantages over vinyl insulation. It won't burn.

If you don't want to believe me look at recalls for potential fire situations in automobiles. Most automobiles are 12 electrical systems. Many if not most vehicle fires including RVs are electrical 12 volt system fires.
So be careful out there if don't know get somebody that does. There's no sure thing, but you'll have a better chance of NOT having an electrical fire.

One more example of low voltage causing fires. USB is 5 volts. How many cell phones and laptop computers have you heard about burning because of an electrical problem.