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srma63
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Join Date: Dec 2010
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Below Grade 12VDC Wiring

12/16/2010 2:54 PM

My landscaper has installed wiring suitable for 12VDC, LED illuminated, pathway light fixtures. He has also recommended that we use below grade junction boxes to make the fixture connections. He believes that there are such boxes on the market that can be anchored to the ground and that have a standard 1/2" pipe thread opening at the top into which the pathway light poles can me mounted. This would alleviate having to use the mounting stakes that came with the fixtures. Are such junction boxes available, and if so, where can I purchase such junction boxes? Also, I assume that I should use waterproof twist connectors for the wires, as there is always the possibility of moisture infiltrating the junction boxes?
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Pathfinder Tags: below grade wiring
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kramarat
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#2

Re: Below Grade 12VDC Wiring

12/16/2010 3:07 PM

Here's some........Wow those are pricey!

http://www.residential-landscape-lighting-design.com/store/PPF/Category/3415_2_0_0_0_0_0_0_0_0/products.asp

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srma63
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#3

Re: Below Grade 12VDC Wiring

12/16/2010 6:51 PM

OK, that answers that question. Now, it turns out that my system (i.e., the transformer that I purchased along with the pathway lights and 12V 20W halogen 2-pin bulbs) is not 12VDC, rather it's 12VAC (at least the transformer output is VAC). Separately, I purchased 12V 20W 2-pin LED cluster towers to retrofit the fixture 20W halogen bulbs (longer life, less wattage, virtually no line drop). The LED don't say whether they are AC or DC, just that they are 12V. Does it matter?
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kramarat
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#4
In reply to #3

Re: Below Grade 12VDC Wiring

12/16/2010 9:05 PM

LED'S run on DC. If output is AC you will have to get a converter.

Google to double check and find wiring diagrams.

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srma63
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#5
In reply to #4

Re: Below Grade 12VDC Wiring

12/16/2010 10:44 PM

OK, that makes sense, however, I've Googled the net have have not found a source for a 12VAC Input to 12VDC Output Converter/Inverter/Rectifier. Any suggestions where I might find one, preferably NEMA3 (outdoor)?
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Big John Mac
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#6
In reply to #5

Re: Below Grade 12VDC Wiring

12/16/2010 11:33 PM

Why not simply add a diode in line with your wiring in the treansformer box? 10 amp are readily available at supply stores, or just get one off e-bay. Does not hurt if you get it in wrong, lights just will not lite up...reverse it then.

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srma63
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#7
In reply to #6

Re: Below Grade 12VDC Wiring

12/17/2010 12:39 AM

Could you be just a little more specific, please? How about a technical description of such a diode or, better yet, a mfg. part number.
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SSCpal
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#9

Re: Below Grade 12VDC Wiring

12/17/2010 10:09 AM

Common LEDs are DC devices, but can be fed on AC, they just won't light on half the cycles and will seem dim. A full-wave rectifier will turn the AC into pulsating DC to keep the LEDs on full time.
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Gazu
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#10

Re: Below Grade 12VDC Wiring

12/17/2010 1:09 PM

Go to your local electronic parts store (Radio Shack or similar) and get a "bridge rectifier". Make sure it is rated for the total load of LEDs. Insert this in the 12v output line near the transformer and enjoy the glow. Be sure it is in the low voltage line or you definitely will NOT enjoy the glow.
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#11

Re: Below Grade 12VDC Wiring

12/17/2010 2:54 PM

Don't bother adding anything in front. The "D" in LED stands for DIODE. Inserting any type of rectifier or AC/DC converter is just putting non-luminous diodes in series with luminous diodes.

Since you've already got the 12V LED clusters, use them. They'll be lower in light intensity because they're only running on 1/2 of the waveform. If you want more light, I suggest putting 2 clusters in parallel with opposite polarities. One will use the upper half-wave, the other the lower half. (In other words, build a bridge rectifier with your LED's.)
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Anonymous Poster (3); Big John Mac (1); Gazu (1); kramarat (2); srma63 (3); SSCpal (1)

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