Anyone do much low voltage landscape lighting (T or hub/spider wiring?)

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ritelec

Senior Member
Location
Jersey
Installing some low voltage transformers and low volyage landscape lighting.

Some literature on internet and that come with transformers say to use hub/spider wiring, To use the 25' lower gauge wire attached to the fixture and bring those back to a hub and that hub gets fed with a home run going back to the transformer.

Other readings say that the hub/spider technique is not efficient and problematic and that a T method should be used.
The T method would be a group of 6 or 10 (or so) connected in a daisy chain with #12's (not the #16 or #18 that comes with the fixture) then a #12 or #10 home run brought from the center fixture of that group to the transformer.

Any preferences from experience ???

Thank you
 

ramsy

Roger Ruhle dba NoFixNoPay
Location
LA basin, CA
Occupation
Service Electrician 2020 NEC
Squirting silicone inside these make the longest lasting, most durable connectors I've found for 12v landscape feeders, and fixture whips, in all kinds of wet, or exposed locations.

Wire_nuts.jpg
 

oldsparky52

Senior Member
Because LV lighting is LV, it is very susceptible to voltage drop problems. That's why the "star" method is suggested. The voltage drop the each fixture is less that the far runs on the "T" method.

I used the "star" method whenever I could, but often used the "T" method taking the home run to the middle of the run then going 2 directions (lower VD at the ends vs starting at one end and going to the next). But, I was doing this prior to LED lighting, and the amperages were higher so it made the VD more significant than you would have with LED lighting.

You should not ignore VD just because it's a LV system.
 

ritelec

Senior Member
Location
Jersey
Thank you. Lol. I'm still not clear which way to go with this.
Star or T ? The arguments for both wiring make sense. I would like to star but one article I read mentioned because of the lesser gauge wire and the 25' length on the whips it puts stress on the trnsformer and lessons its
Efficiency and life ???? The fixtures will be 95% if not 100% led.
If you were going to start wiriing which method would you do hands down with no second thoughts ??


Also. I was/ am going to pick up silicone wire nuts Is it just regular silicone in there or some type of electrical rated. I'll still get them as they seem to be rated for it and also are designed to close at the bottom by curious if it is special silicone.

Thank you for the info.
 

drcampbell

Senior Member
Location
The Motor City, Michigan USA
Occupation
Registered Professional Engineer
... You should not ignore voltage drop just because it's a low-voltage system.
That's the understatement of the week. Voltage drop is a LOT more important in low-voltage systems.
(I think we discovered that about 1885 and have been raising transmission & distribution voltages ever since)

Ohms Law is your friend. Use it. Sketch out a few options on paper and calculate how they'll work before hooking anything up.
I guarantee it will yield the answer. (which might end up being "the different configurations all perform about the same")
 

ritelec

Senior Member
Location
Jersey
It's not crazy going ons.

I did a sketch and will decide which lights to put where and on what.

There's three sections or areas of plantings of bushes scrubs and small trees.


Rectangular areas of about 70'x 30' where I set up a transformer for each section.


I will be lighting various spots in each section and running home runs back to each transformer for that section.

Wondering if I should star or T it's not a big deal to do either. If I had the option which is the best to way to wire. A star or T ???
 

ritelec

Senior Member
Location
Jersey
Least wire would be home runs to star, T would be more wire with home runs and branching to each fixture removing factory wire....

Star it is..... thank you
 

ritelec

Senior Member
Location
Jersey
Ahhhhh !!!!

I can't commit to Star, I read this and it gets me second guessing

https://www.turfmagazine.com/landscape-designbuildinstallation/landscape-lighting-wiring-101/


then I read this and think T

https://landscape-business.com/landscape-lighting-voltage-drop-and-wiring-methods/

https://www.landscapelight.com/design-installation-support/low-voltage-system-layout/

and then see book that came with the transformer (pic enclosed) and last comment here and think Star again.......smh

flip a coin ?
 

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oldsparky52

Senior Member
...
Wondering if I should star or T it's not a big deal to do either. If I had the option which is the best to way to wire. A star or T ???

...

Ohms Law is your friend. Use it. Sketch out a few options on paper and calculate how they'll work before hooking anything up.
I guarantee it will yield the answer. (which might end up being "the different configurations all perform about the same")

You answer is there. The layout will show you the best method.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
I would not prefer to splice large group of wires. We have used LV cable as large as #8 copper for extra long runs and then drop down to #10 or #12
 

ritelec

Senior Member
Location
Jersey
No, just share the layout with us. :)

gotta figure out the layout.... I'm not sure how much light (lumens) these fixtures are going to put out in real life. I have some charts showing
3 watts led = 25 watt incandescent@ (250 lumens). 4-5=40@450. 6-8=60@80. 9-13=75@1,100...
I have an idea what the 450 lumen (40 watt incandescent) looks like, but path lights at 3 watt led @150 lumens from one manufacturer or 2-2.5 watt led at 110-115 lumens. ??? or bullets at 2-4-6 watts led???
I may by a couple fixtures or a fixture with assorted bulbs and see what the light will actually look like.
 

oldsparky52

Senior Member
gotta figure out the layout.... I'm not sure how much light (lumens) these fixtures are going to put out in real life. I have some charts showing
3 watts led = 25 watt incandescent@ (250 lumens). 4-5=40@450. 6-8=60@80. 9-13=75@1,100...
I have an idea what the 450 lumen (40 watt incandescent) looks like, but path lights at 3 watt led @150 lumens from one manufacturer or 2-2.5 watt led at 110-115 lumens. ??? or bullets at 2-4-6 watts led???
I may by a couple fixtures or a fixture with assorted bulbs and see what the light will actually look like.

Sounds like a project of some significance. Have you asked the supplier to offer design assistance? They do that stuff all the time, you don't have to follow there recommendations, but they may have some experience that can be beneficial.

Of course never forget they are selling. :) Buyer beware.
 
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