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View Full Version : how deep do you bury landscape lighting?


Trenchblade
03-17-2008, 10:59 AM
Just looking for some info on how deep to bury low voltage lighting?

JoeyD
03-17-2008, 11:22 AM
No less than 6in. for main lines/home runs is what I believe the NEC says. It is different for different areas in the landscape such as running under hardscape has a different rule I believe. What we do for our fixture leads (not home runs) is we leave them just a few inches down and explain to the homeowners that if they do any replanting in the area it is real easy for them to trace the wire up back tot he HUB and move the lights aside if need be. Reason is that a shovel will go through wire at 6in just like it will at 2in so at least they can move the wire out of their way. Try and always keep your wires along an edge if you can, good practice and then you can explain that to them as well. Obviously when going through lawn areas, especially those that are aerated you must go deeper as to prevent damage.

INTEGRA Bespoke Lighting
03-17-2008, 11:31 AM
Well, I try not to bury my low voltage lighting at all! Doing so would seriously limit its ability to light anything up. :)

I do however bury the associated wire and connectors. I operate in a rather rugged environment here with lots of roots and rocks so trenching wire in is a real pain. Here our rule is 6" deep unless the conditions do not allow for it. In some cases we have to thread the cable under the tree roots and across the forest floor and then use staple to pin it all down, raking mulch over top. Abrasion protection is a very real concern here too, necessitating the use of poly pipe as a conduit in some places.

Have a great day.

Trenchblade
03-17-2008, 11:39 AM
thanks for the input. I have a product that I am thinking of getting behind. It works real good for trenching bed lines, but they are also thnking of marketing it tward low voltage lighting and invisible dog fence wiring and i am looking to see it it may be something lighting pros might use also. You can see some info about the product at www.trenchblade.com

INTEGRA Bespoke Lighting
03-17-2008, 11:54 AM
thanks for the input. I have a product that I am thinking of getting behind. It works real good for trenching bed lines, but they are also thnking of marketing it tward low voltage lighting and invisible dog fence wiring and i am looking to see it it may be something lighting pros might use also. You can see some info about the product at www.trenchblade.com

That thing would not last 2 mins here.

There are many other more effective mechanical devices developed for trenching wire into the ground. EZtrencher comes to mind, as well as proper vibratory plows by Ditchwitch, Vermeer, etc.

After you buzz along with that toy, where are you going to find all the soils with which to in-fill your trench? It seems that thing spreads the soil far and wide with its out of control RPMs.

Regards.

klkanders
03-17-2008, 12:15 PM
I agree with James. High RPM's = danger! That product is better suited for homeowner use as it doesnt look like it will dig much lower then the sod depth. If it came into contact with a rock tho.....lookout! We had a guy using a trimmer with a brush cutter on a few years back that caught a rock half submerged in the ground. A piece of the blade broke off and caught him in the neck! Nasty wound but it could have been much worse.
A shovel works best for me. If I have to go long distances I would use our Brown bed edger with a narrow blade. It sets the soil right next to the trench.

NightScenes
03-17-2008, 06:01 PM
I would have to say, no thanks. I can just see my guys getting ripped up by shrapnel now.

Mike M
03-17-2008, 08:10 PM
When I asked my JDL rep for trenching tools he had for lv cable, he said, "Why bother? Just cover it with mulch."

So, there ya go!

Pro-Scapes
03-17-2008, 11:57 PM
When I asked my JDL rep for trenching tools he had for lv cable, he said, "Why bother? Just cover it with mulch."

So, there ya go!

thats why he is a desk jockey and not a reputable contractor. He couldnt hack it.

There has been a handful of times I have been asked to leave the wire under the 3 inches of mulch especially in seasonal planting areas. I usually preffer to bury it as deep as possible and contain it in conduit in these areas.

Mike M
03-18-2008, 08:14 AM
I tell the customer if they are going to plant near the fixtures, to just remove the stake and slack wire and put it to the side. Code is 6 inches, but I believe we can include the mulch in that depth. I just use my shorter ruler and I'm set, lol.

I'm getting better at planning for some conduit and allowing for longer winding runs if necessary to steer my home runs out of planting beds.

The Unique rep in FL showed us a simple technique for retrofitting conduit; after you cut the pvc to the length you need, make a horizontal slot along the whole piece. Pop in the wire, and there you go.

steveparrott
03-18-2008, 08:43 AM
Just looking for some info on how deep to bury low voltage lighting?

Here is the code (NEC article 300.5) for burial depth of low voltage wiring. A summary:

-All locations not specified below - 6 inches
-In trench below minimum 2" thick concrete - 6 inches
-Under a building - In raceway only
-Under roads, alleys, public driveways and parking lots - 24 inches
-Under one- and two-family dwelling driveways and outdoor parking areas and used only for dwelling-related purposes - 18 inches
In or under airport runways, including adjacent areas where trespassing is prohibited - 18 inches

Note: Conduits are not required for any of the outdoor applications as long as UL-listed direct burial wire is used. Also note that sidewalks are not specified, although the '2" thick concrete' clause probably applies - 6" - measured from top of wire to top surface of paving.

Pro-Scapes
03-18-2008, 09:13 AM
Keep in mind you should go a deep as you possibly can at edges of concrete and in lawn to bed transitions or any other place the wire can potentially be cut with edging or other main equipment. We also try to route our runs out of harms way when possible and NEVER bury in a flower bed edge.

some guys will try to tell you UP TO 6 inches. I didnt see the words "up to" in Steves posting of the code.

The product link in question would be a no no for LV cable. It will not go deep enough. You will get 3.5 inches with that max considering an edger blade is about 8 inches long. I can just see it now... replace every window in the house with a new lighting system. I came up with an idea and mock up for a hand held trencher but after seeing the saftey aspect of it I quickly abandoned it. DMR has the safest looking small trecher/wire installer I have seen yet. We still hand install everything

Trenchblade
03-18-2008, 09:16 AM
Thanks for all of the input. It has been very insightful.:)

The Lighting Geek
03-18-2008, 10:48 AM
Here is the code (NEC article 300.5) for burial depth of low voltage wiring. A summary:

-All locations not specified below - 6 inches
-In trench below minimum 2" thick concrete - 6 inches
-Under a building - In raceway only
-Under roads, alleys, public driveways and parking lots - 24 inches
-Under one- and two-family dwelling driveways and outdoor parking areas and used only for dwelling-related purposes - 18 inches


That describes how I train my guys along with pretty much what Billy said as well. You don't want it to come back to you later. When hit a job with massiv e trees and roots that prevent burying we tell the customer to put 6" of mulch to cover. They usually do it because they don't want to look at the wire or take a chance it gets damaged. Anytime you are not sure, check the NEC.

David Gretzmier
03-20-2008, 07:32 PM
I believe I may be the only installer in my area going as deep as 4-6" deep. EVERY job I retrofit has had it just below the mulch. I can't count the annual beds I have tilled and hit a low voltage cable.

I've read about a ton of guys say they install wire with a spade, as I do, and I'm pretty sure I hit a minimum of 4", but jumping on a sharp spade with both feet, and rocking back and forth, then using a blunt tool to shove the cable in the resulting "V" does not equal 6 inches. maybe in sandy soil areas, but not where the dirt is brown or red.

In the last 7 years, I have not had a single callback because folks cut through my lines, So I sleep ok at night. I think 6" is a good goal, but without a mechanical trencher it is not really doable in my area.

ok, now everyone throw rocks at me.

INTEGRA Bespoke Lighting
03-21-2008, 10:21 AM
David, you want rocks? Come on up for a visit, because I have rocks by the barge load for you here. :canadaflag:

Installing LV landscape wire (or any wire for that matter) into 4 Billion year old Precambrian Shield can be a real challenge! Routing and cable protection are issues on almost every job we install. The conditions result in us using a LOT of wire. The last time I did a comparison, I was using 4x more wire per fixture then typical suburban lighting companies. (our lots are very large too, typically between 3 and 15 acres)

Now if Tesla had only managed to perfect transferring electricity through the ether before his lab burned down! You working on anything like that at the factory Joey? :)

JoeyD
03-21-2008, 10:33 AM
Actually James I am, it's called the 24v system!! It's coming...........

INTEGRA Bespoke Lighting
03-21-2008, 10:37 AM
Actually I was thinking more of an LED system with really low current requirements that could be powered by microwave energy. Then, like a wireless network, you would simply have a router distributing the energy out to receivers that are then powering the fixtures.

Who knows... maybe someday?

JoeyD
03-21-2008, 10:42 AM
James does that mean I could use this microwave energy to heat my hot pockets and fire my lights up? I'm sold, I love hot pockets!!!

Actually it's forward thinking like this that today we may laugh about but in 15-20 years may be reality. You never know. You better register that idea before someone else does........ Trust me someone will take it and call it their own!!

INTEGRA Bespoke Lighting
03-21-2008, 11:09 AM
Not having the millions of dollars necessary to do the R&D on such an energy transference system sort of makes my my idea just that... and ideas are a dime a dozen these days.

12 years ago I had an idea that would see small LCD screens installed into picture frames where you would download digital images and have a dynamic photo display. (Im not joking). I thought it all through, and then came up with the idea of such panels that would install onto/into your refrigerator too. I did my best to contact a number of 'players' in the digital imagery and computer business... I contacted Microsoft, Apple, Kodak, Canon, Whirlpool and Inglis. Didn't get very far though. The one person I actually managed to speak to about this said "it will never fly... too expensive" Now you can buy the darned things at Best Buy for a few bucks, and LG has a fridge version built into their high end units!

So, there you go... ideas are easy, its the capitalization of those ideas that is the very hard part. If anyone knows any Angel Investors out there, I have a whole bag of ideas like that just waiting for someone to believe in them.

Have a great day.

Chris J
03-21-2008, 10:59 PM
Not having the millions of dollars necessary to do the R&D on such an energy transference system sort of makes my my idea just that... and ideas are a dime a dozen these days.

12 years ago I had an idea that would see small LCD screens installed into picture frames where you would download digital images and have a dynamic photo display. (Im not joking). I thought it all through, and then came up with the idea of such panels that would install onto/into your refrigerator too. I did my best to contact a number of 'players' in the digital imagery and computer business... I contacted Microsoft, Apple, Kodak, Canon, Whirlpool and Inglis. Didn't get very far though. The one person I actually managed to speak to about this said "it will never fly... too expensive" Now you can buy the darned things at Best Buy for a few bucks, and LG has a fridge version built into their high end units!

So, there you go... ideas are easy, its the capitalization of those ideas that is the very hard part. If anyone knows any Angel Investors out there, I have a whole bag of ideas like that just waiting for someone to believe in them.

Have a great day.

Are you real sure you are not related to Al Gore?

pete scalia
03-21-2008, 11:21 PM
Are you real sure you are not related to Al Gore?

Are you hinting that Gore didn't invent the internet?

Some people are delusional as is the case with the aforementioned post.

pete scalia
03-21-2008, 11:24 PM
Not having the millions of dollars necessary to do the R&D on such an energy transference system sort of makes my my idea just that... and ideas are a dime a dozen these days.

12 years ago I had an idea that would see small LCD screens installed into picture frames where you would download digital images and have a dynamic photo display. (Im not joking). I thought it all through, and then came up with the idea of such panels that would install onto/into your refrigerator too. I did my best to contact a number of 'players' in the digital imagery and computer business... I contacted Microsoft, Apple, Kodak, Canon, Whirlpool and Inglis. Didn't get very far though. The one person I actually managed to speak to about this said "it will never fly... too expensive" Now you can buy the darned things at Best Buy for a few bucks, and LG has a fridge version built into their high end units!

So, there you go... ideas are easy, its the capitalization of those ideas that is the very hard part. If anyone knows any Angel Investors out there, I have a whole bag of ideas like that just waiting for someone to believe in them.

Have a great day.

The respectable companies mentioned above have a solid long standing policy of not dealing with crackpots that suffer from acute delusions of grandeur.

steveparrott
03-23-2008, 06:15 PM
Are you hinting that Gore didn't invent the internet?

To set the record straight, Al Gore never claimed to invent the Internet (that was right wing spin). Gore claims credit for taking initiatives that led to the creation of the Internet. He was a senator at the time and spearheaded the creation of federal grants that supported that work. His "High Performance Computing Act" provided the funds for researchers that invented the Internet. Without Gore's support of that work, we might not have the free and open forum that we enjoy today.

Mike M
03-23-2008, 06:39 PM
Al Gore invented global warming.

JoeyD
03-24-2008, 12:40 PM
Al Gore is funny!