# Outdoor 18 ga wire vs. 18 ga Lamp Cord?



## Greg Di (Mar 12, 2005)

Can someone with an electrical background please explain the difference to me between 18 gauge Outdoor Low-Voltage wire and 18 gauge Lamp cord?

I cannot tell any perceivable difference between the two when holding them side by side. In fact, I doubt you could either.

The reason I ask is that I am having a hard time finding 18 ga outdoor wire locally and the LV LED light system I install specs 18 ga wire rather than the bigger stuff since the LEDs don't really draw the amps incandescents do.

I do not bury the wire and it's only carrying 12V DC. 

Am I crazy to think that lamp cord wouldn't do the job perfectly????


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## dlcj (Oct 1, 2007)

its not the wire inside thats differnt its the insulation. Most indoor lamp cord and romex does not have a water proof cover. If you cannot find outdoor lv cord in bulk then try a trailer supply store. The wire they use for wiring the lights on utility trailers and big rig trailers will work fine and is for outdoor use but not to bury.


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## Celtic (May 23, 2007)

Greg,
if this is not a "home project"...you do realize you'll need a bona fide EC for this.



> 45:5A-18. Exempt work or construction
> Electrical work or construction which is performed on the following facilities or which is by or for the
> following agencies shall not be included within the business of electrical contracting so as to require the securing
> of a business permit under this act:
> (j) Any work with a potential of less than 10 volts.


http://www.nj.gov/lps/ca/electric/eleclaws.pdf
[pages 27 - 28]

I'm not trying to blow smoke up the fireman's butt...
http://www.nj.gov/lps/ca/electric/minutes/elemin_070208.htm
...people get nailed every month with fines starting at about $1000.

I'd rather you be aware than be caught with your pants down.


*::Climbing down from the soap box::*

You had no luck at the big box stores?
Can you use a larger size [say #16 ???]..it seems readily available at big box?​


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## Greg Di (Mar 12, 2005)

Celtic said:


> Greg,
> if this is not a "home project"...you do realize you'll need a bona fide EC for this.
> 
> http://www.nj.gov/lps/ca/electric/eleclaws.pdf
> ...


I'm well aware. Well aware....


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## Greg Di (Mar 12, 2005)

dlcj said:


> its not the wire inside thats differnt its the insulation. Most indoor lamp cord and romex does not have a water proof cover. If you cannot find outdoor lv cord in bulk then try a trailer supply store. The wire they use for wiring the lights on utility trailers and big rig trailers will work fine and is for outdoor use but not to bury.


Exactly how does water penetrate the insulation on lamp cord or romex? Is the insulation porous?

The 24 ga wires from my LED fixtures sure looks to be nothing special.


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## dlcj (Oct 1, 2007)

Greg Di said:


> Exactly how does water penetrate the insulation on lamp cord or romex? Is the insulation porous?
> 
> The 24 ga wires from my LED fixtures sure looks to be nothing special.


damn if i know how. I just know i have opened up non-burial romex that has got rained on and the paper insulation on the ground would be wet. Maybe it just wicked up the end but i try my best not to let any get wet.


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## Celtic (May 23, 2007)

Greg Di said:


> Exactly how does water penetrate the insulation on lamp cord or romex? Is the insulation porous?


THAT is one of the greatest mysterious of insulation.

No one can tell me exactly what type insulation is on Romex wire.....they can tell me it is not THHN/THWN [rated for wet use], but that's about it.

We're gonna need Leonard Nimoy on this:


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## mickeyco (May 13, 2006)

What about a UV rating for low voltage cable?





.


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## Bkessler (Oct 8, 2005)

mickeyco said:


> What about a UV rating for low voltage cable?
> 
> 
> .


The deck builder may be right, the answer lies in artical 310.13 check the letter codes on the wire and compare to the table. You may need a magnifying glass.


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