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ACutAboveNC
08-25-2007, 06:07 PM
We have a customer that we are installing landscape lighting for in the front and back yards. We are going to complete the project in the fall but in the meantime her irrigation had to be reinstalled due to a lot of failures by a sub contractor which included his wiring of the control panel for the system. Well, an electrician shows up and they get to talking about her landscape lighting. We ran 12 gauge wiring through the irrigations trenches to simplfy our job this fall but that will soon be comprimised because this electrician has convinced her that we are idiots for not using 8 gauge. We have installed 2 other systems with 12 gauge and had no problems with the wiring. We even have a family friend who is an electrician confirm our way as an ok way. I think some people are just out for the money when they see they have a fish on the line and it really bugged me that she might be takin for a ride. She is a neighbor and a really wonderful lady but I feel she is having the wool pulled over her eyes. Am I wrong?

NightScenes
08-25-2007, 06:19 PM
No, you are not wrong. You need to educate her as to what kind of load you are planning for the areas and what size wire will be needed to handle that load. Then you can show her the cost difference between #12 and #8 wire. Sometimes we have to educate our clients so they are not taken advantage of.

Pro-Scapes
08-25-2007, 06:20 PM
no one can answer your question without details

in some cases 12ga is fine. In some cases only 8 or even multiple runs of it will do. Just because the other systems worked with 12 doesnt mean this one will.

How long are the runs?
What method will you use to hook up the lights (Im guessing daisy chain)
How many watts are on the run?
What voltage taps are avalible on your trans ?
Will you need the room to expand or up the wattages later as plants grow ?

The elctrician could be right or he could be trying to steal the job from you. Alot of electricians are clueless when it comes to low voltage lighting but others know thier stuff.

Good rule of thumb.

if its over 100ft or over 100 watts run 10 ga or better wire.
Short runs with low wattages have no problem running 12ga

At this point in the game you should have a drawing or at least good notes with the lenght of runs and thier wattages and the calculations.

I hope you also sealed up that prewire to prevent moisture from wicking up the lines. Just snap a grease tube over it.

klkanders
08-26-2007, 01:00 PM
Good avice from Paul and Billy. Find out what the lighting needs are going to be now and adding a few in future. Just sitting down having an informative session with the customer and deciding what both parties objectives are will clear this up. When this is done and you know how many lights, wattages are on each run you can then prove what wire gauge is needed. Like Paul's last line educating the client is the way to go so they feel comfortable that you care and are not just telling them you have to do this because I said so.

NightLightingFX
08-26-2007, 01:20 PM
I have only been doing this for two years, so maybe I have no idea what I am doing. But I have never used 8 gage on any of my jobs. Heck, I have only used 12 gage. I have gone almost 200 ft with 12 gage. I was obviously using a tap that was above 15 volts. I would guess that is where I would get some criticizm regarding the UL 1838 issue. I have been considering using 10 gage for my long runs. In my opinion, it seems like 8 gage is way overkill.
~Ned
www.nightlightingfx.com

NightLightingFX
08-26-2007, 01:30 PM
I would just like to add to my previous message. That I always check my amps and volts. Especially on the long runs. Using 12 gage wire if my run is over 16 amps I will go to the drawing board. To be honest i don't think I have ever seen any of my runs over 14 amps. It seems like my 12 gage homeruns usually run around 8 and 13 amps.
~Ned
www.nightlightingfx.com

Pro-Scapes
08-26-2007, 01:38 PM
if you do country installs like paul and I do you might need 8ga. I chose to run 2 strips of 10ga (no not in parralel paul I learned my lesson on that) instead of a run of 8ga... it was actually cheaper and enabled me to split the hub across 2 runs.

8ga does have its time and place I probably wouldnt run 14a on a single 12ga tho either

NightLightingFX
08-26-2007, 01:57 PM
Billy,
For future reference, and I m not challenging you I want to know all the tricks of the trade. What was the circumstance that you used 8 gage wire? Thanks for your input
~Ned
www.nightlightingfx.com

JackTorsed
08-26-2007, 02:16 PM
Billy,
For future reference, and I m not challenging you I want to know all the tricks of the trade. What was the circumstance that you used 8 gage wire? Thanks for your input
~Ned
www.nightlightingfx.com

long cable home runs

Pro-Scapes
08-26-2007, 06:07 PM
Billy,
For future reference, and I m not challenging you I want to know all the tricks of the trade. What was the circumstance that you used 8 gage wire? Thanks for your input
~Ned
www.nightlightingfx.com

100w hub at 335ft. Was cheaper to install the 8ga than have electricity and another trans out there. If you would of needed several runs of it to 1 area at that distance you would be best off to have the line voltage installed and add a transformer. At least most the way out there. In this case it was to a driveway entrance for 5 lights. I was a bit soft on the voltage when it was done and on a 15v tap.

Estimate from electrician to install line voltage was over 3 times the cost for me to run the 8ga (we used machinery to bury this). Some of you may of still run 12ga and used a 21v tap. This is not part of my practice and I will never do that. I reckon I could of done the 10ga but my trans only went to 15v

NightLightingFX
08-26-2007, 06:35 PM
That makes sense. Since I was born into the industry through Unique I am more familiar with using only 12 gage. And I pretty much feel my max length I can go is 200 feet. However, considering using lower gage can be a real option. Which I my adopt down the road. Thanks
~Ned
www.nightlightingfx.com

JoeyD
08-26-2007, 08:23 PM
That makes sense. Since I was born into the industry through Unique I am more familiar with using only 12 gage. And I pretty much feel my max length I can go is 200 feet. However, considering using lower gage can be a real option. Which I my adopt down the road. Thanks
~Ned
www.nightlightingfx.com

Ned

200ft 200w 12v on 12/2 w/ a 22v tap.

You can go farther just need to drop wattage

Pro-Scapes
08-26-2007, 08:34 PM
Ned

200ft 200w 12v on 12/2 w/ a 22v tap.

You can go farther just need to drop wattage

Ruh roh raggy (in my best scooby doo voice) thats not good. MIN absolute MIN should be 10ga.

192w max on 12ga please and this is ABSOLUTE MAX. Do yourself and your clients a favor and never MAX things out this bad.

Ned stick to the 100w 100ft rule. Will serve you well for expansions. Also an excellent selling point too! Its more effecient so you wont be wasting wattage on the wire and putting it to the lamps where it should be

12/2 192w or 16a but reccomended is 100w or about 8.5a
10/2 is 288w or 24a max but reccomended varies between 140 and 200w depending who you ask and the avalible taps and lenghts.

I heard nate suggests the 22v taps and thier usage in his book. I have yet to read it.

NightScenes
08-26-2007, 10:13 PM
Remember Ned, you can only load a wire to 80 percent. That is 16 amps on 12/2 wire.

Chris J
08-26-2007, 10:23 PM
It doesn't matter who says it. The calculations are what they are. 12/2 wire is rated for 20 amps. 10/2 wire is rated for 30amps.
20amps x 12v= 240 watts max on 12 guage wire.
30amps x 12v= 360 watts max on 10 guage wire.
I never push these limits, but as long as you understand the characteristics of cable loss and the dynamics wire resistance there is no reason you can't go straight up the the 80% rule of these limits. I wouldn't bother with limiting yourself to anything less than that just because someone "recommends it."

NightScenes
08-26-2007, 10:56 PM
Chris, you are talking about max amperage. NEC says that you can not load a line at more than 80%. That is code.

JackTorsed
08-27-2007, 12:19 AM
Ned

200ft 200w 12v on 12/2 w/ a 22v tap.

You can go farther just need to drop wattage

Nate's an electrician by trade and is going to be upset with you Joe.:waving:

He preaches 80% load maximum as per NEC

12 gauge wire woud be 192 VA or 16 amps

Pro-Scapes
08-27-2007, 12:53 AM
poor joey sure is taking a beating tonight. Everyone fed ex Joe a cold one :drinkup:

Bullet proof systems are NOT built by pushing the limits. Even something made to perform like a ferrari wont have a very long life expectancy if you ride around with the pedal on the floor. Build your systems to cruise with room to add some horsepower (future fixtures)

Much MUCH easier to upsell additions later if they are hassel free. This includes room on the wire and at the trans. Anyone here I think will tell you that clients add fixtures or you may need to change wattage as plants and trees grow in the future. Its this type of planning and watching out for your clients that is another way of setting yourself apart from your competition.

I stress this with each and every system we propose. Systems are engineered and designed to allow reasonable expansion and increases in wattage as plants and or needs grow.

We did one about a year and a half ago... installed a 1200w trans but only had about 760w running on it initially(could of used a 900w). Same trans is now what I would consider about full(about 85% or 1020w). Stone reliable.

JoeyD
08-27-2007, 09:51 AM
Nate's an electrician by trade and is going to be upset with you Joe.:waving:

He preaches 80% load maximum as per NEC

12 gauge wire woud be 192 VA or 16 amps


Hey I preach 80% all day always have. 200 is just a btt easier to remember than 192 sometimes but the minute I sent that i knew I was going to catch heat with all you pirahnas!!!!!

Chris J
08-27-2007, 12:36 PM
Chris, you are talking about max amperage. NEC says that you can not load a line at more than 80%. That is code.

That's exactly what I said! You can go all the way up to 80% of the maximum rating of the wire. I was simply saying that there is no need to listen to any "recommendations" to go even lower than 80%. Those recommendations are for the amateur who does not understand cable loss and "increased wattage" when using extremely long runs.

Eden Lights
08-27-2007, 01:43 PM
A few times over the years I have been called to a project were wire was ran in the irrigaition trenchs by various trades. In my experience this was done with no planning or design. Let's say a 12/2 to every irrgaition zone was the plan, the problem is the long and crazy route and terminations that maybe the wire is ran in. I tell my customers to expect that none of the prior wire will be useable and if you can use one or maybe two your lucky and can pass the savings along. 12/2 just thrown in the trenches opens yourself to get slammed by other professionals and I have to agree with them in most cases.

NightScenes
08-27-2007, 03:09 PM
That's exactly what I said! You can go all the way up to 80% of the maximum rating of the wire. I was simply saying that there is no need to listen to any "recommendations" to go even lower than 80%. Those recommendations are for the amateur who does not understand cable loss and "increased wattage" when using extremely long runs.

I gotcha, I misunderstood what you were saying Chris. I guess my reading and your speaking weren't meshing together. Anyway, I think everyone is on the same page now.

Yeehhhaaaawww