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Low voltage LED night lights - options to wire them?

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Mar 26, 2013, 12:37 AM
Joseph Urban
Low voltage LED night lights - options to wire them?
Is it reasonable to run low voltage throughout the house to power LED nightlights instead of running 120VAC to individual units, each with its own transformer? Why not just have one centralized ballast? Are there any code issues - especially in California?


--Joe
Mar 26, 2013, 11:42 AM
swschrad
it's called Ohm's Law. all wire has resistance. the resistance is pressure against the voltage on the line, and end to end in a house, the 100 feet will cause uneven LED brightness.

LED lighting includes its own resistance to limit the current across the chip, and thus the brightness. the wire drop, assuming the usual serpentine wiring of homes which can double effective distance, will even cause a few of the LEDs to not light.

with 120 volt devices, none of which are currently semiconductor and require current limiting, you don't see the 5-8 percent line drop as an issue.


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Mar 26, 2013, 04:39 PM
CommonwealthSparky
It depends on your set up. If all the runs are exposed then flexible cords and cables are allowed. But if any cable is placed in an concealed space [wall cavity] you run into trouble. {NEC 400.8} Then that run has to be cable approved to be run inside concealed areas. E.I. Romex, armored cable, etc.
I agree with swschrad that voltage drop becomes a much bigger issue at say 24v than it is at 120v. Depending on what your lay out is this can be a problem.

This message has been edited. Last edited by: CommonwealthSparky,


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