View Full Version : 500' Ditch for Low Voltage Lighting

05-10-2008, 11:09 PM
Anyone have any tips for cutting a ditch WITHOUT using a walk behind ditcher? I've thought about using an edger or a single tine tiller, but wanted to ask you pros first. I would appreciate any advice you guys might have.

05-11-2008, 12:34 AM
What gauge wire are you planning to use and what is your lamp load ? Do you know what kind of voltage you will loose at 500' ?

You fail to mention what the terrain is like. If it was a lawn I would bite the bullet and use a spade or a vibe plow. By the time you set up the vibe plow tho and repaired anything you damaged you could of just done it the old fashioned way and slit trench it.

Chances are at 500' we would be adding line voltage closer to the area we needed to light.

05-11-2008, 01:01 AM
Thanks for the reply.
I'm coming off of (2) 600W transformers and adding (15) 20W wall wash fixtures to an existing system that I put in last year. One transformer is by the front door and the other is at the back wall. I don't plan on going over 300 feet with either circuit and splitting the lights as needed. And I'm using 12gauge wire. But the ditch will be a total of 500 feet.
Here in Odessa, Tx., we have a lot of cliche and I know I have that for the top 12 inches but I plan on going only 6 inches or so deep.
I think I know what a vibe plow is, but what is a slit trench?

05-11-2008, 01:32 AM
Slit trech equals spade.... Kick....lift....tuck wires... good luck on the Cliche. If its that bad forget the vibe plow.

12 ga that far with that kind of load ? Ouch.... how high does your voltage on your trans go ? Do you know how to calculate voltage drop? If your careful you could do 3 runs of 12ga if you have about a 20v tap. Your looking about a 7.5- 8v loss. Thats just aproximate assuming 300ft at 100w load. Much better off either running heavier wire or placing line voltage closer to the area you intend to illuminate.

05-11-2008, 08:30 AM
I would at least be using #10 wire for those runs with those loads. If you use 12 and then have to add a light later you will end up having to run another line. I'm in central Texas which is also very rocky and we just do everything by hand. I have used a concrete saw before though on a ground that was as hard as a rock and it worked pretty well.

05-11-2008, 11:08 AM
I would at least be using #10 wire for those runs with those loads. If you use 12 and then have to add a light later you will end up having to run another line. I'm in central Texas which is also very rocky and we just do everything by hand. I have used a concrete saw before though on a ground that was as hard as a rock and it worked pretty well.

I gotta agree,,,, 10ga is an absoute minimum for what I would use here. I would really push for a line voltage drop someplace closer tho. If its really not feesible to add line voltage then 3 drops of 10 or even 8ga. All depends on how high your trans goes.

David Gretzmier
05-11-2008, 04:58 PM
most charts I looked at don't reccomend a greater load of 35 watts at 300 ft using 12 guage or 60 watts at 10. at that wattage load, you can do it, but only if you have taps at around 15 volts. even then you gotta be careful on what voltage/wattage is at fixture 1 on that run verses fixture 3. 35 watts on 12 guage doesn't even get you 2 fixtures in most cases. be careful.

05-11-2008, 05:45 PM
Go to a 24 volt system.

05-11-2008, 06:36 PM
the 24v system would be great in this situation but since he had planned to run 12ga already and didnt seem concearned about the drop I didnt want to toss a 24v system into the works. 24v does have some potential in the right hands. No offence to the original posted but im not certain of the qualifications.

Joey will pop in tmrw and drop the ball on 24v or just using a 22v tap.

I still preffer closer line voltage in this scenario.

05-11-2008, 11:05 PM
Sounds like what you guys are telling me is that the Hampton Bay 600W transformers won't do what they say they will. Are you saying they won't handle 600 watts of lights?
I think I can design it so that my longest run will be 150' with 6 20W lights and use 10 gauge wire.

Chris J
05-11-2008, 11:21 PM
It will handle 600w, but that's not what they are telling you. Resistance in the wire will cause voltage drop. The longer the runs, and/or the more watts you put on the run, will increase the amount of drop. At 150' with 120w on the line, you will have about 3 volts of drop. If your hampton bay tranny has a 15v tap, that scenario should work. However, at 200' with 120w on it, you are going to have more than a 4 volt drop. You will need a 16v tap, and I don't think your transformer has that.

05-12-2008, 12:19 AM
Hampton bay is the same as Malibu if I remember correctly. They are strictly a single tap plastic fire hazard. Your lights will be very dim and you will be doing your customer a disservice by making them constantly replace light bulbs. And if you daisy chain them, they will be even more effective in the rate of failure.

05-12-2008, 12:55 AM
I certainly don't want a fire hazard, and have noticed that bulbs only last 3-4 months.
I have a total of 750' around the house and wall. I want a total of (24) 20w wall wash fixtures and (6) 35w spots, placed evenly around the house and wall. I have (22) 120V outdoor CFCI receptacles spaced 25' apart around the whole length of the 750', so I could put transformers anywhere.

I will definitely get rid of the HB junk. What brand of transformers and layout would you recommend? I appreciate all the info and help.

05-12-2008, 01:20 AM
Also, are HB and/or Malibu fixtures as much junk as their transformers?

05-12-2008, 08:00 AM
ok now that we have determined your a do it yourselfer it changes the whole game.

This is an advanced layout your speaking of and needs to be delt with accordingly. The only way you will get this project done right is with multi tap transformers and alot of knowledge on wiring techniques.

Simply placing malibu or hb transformers everywhere will cause a couple of issues... 1 its still substandard equipment that performs like a wet paper airplane and 2 your transformers will not be coming on at the exact same time so it will look kinda funky

Its a nice house... I would really have to say you need to hire a pro in on this one if you want things to perform like they should.

05-12-2008, 09:58 AM
At 300 ft I could power up to 100w and still get 12v to the lights on 12/2. It wopuld require a 20v-22v tap. On 10/2 at 300ft I could power up 180w and still get 12v to it by using the 22v tap.

But obviously 24v would be the way to go. 300ft on a 24v system is like 100ft on a 2v system. But if it is a DIY job then I would not recommend any of this without a professional involved.

05-12-2008, 11:30 AM
You have crossed over to the realm of the Professional Outdoor Lighting Designer/Installer. If you do not have a good working knowledge of OHMs LAW and the relationship between watts, volts and amps you should not attempt to do this project on your own. A system like this requires significant engineering of equipment capabilities and capacities. The type of equipment required for a project like yours is not available at your local big box store. Transformers, cable, and trenching aside...the selection of the proper lamps for your project will be key. Lamps must be selected based on wattage, beam spread, as well a kelvin temp, CRI and object to be lit. These are but a few of the considerations that make a custom outdoor lighting system a craft requiring skills in both art and science.

You have a beautiful home, it deserves to be done right. Get yourself a pro with the credentials and experience to work with you.

05-12-2008, 02:49 PM
I have a client who owns a home in Midland that she wants me to come light for her. I would be happy to come to Odessa (if it doesn't have to be right away) and take a look at this project if you like. Just let me know.

05-12-2008, 11:13 PM
Steve, I know Paul personally and if you really want that amazing home of yours to look incredible I would seriously consider taking that offer if your able to do so. You would get something outstanding and hassle free. A total turn key package.

05-13-2008, 01:05 AM

I only wish it were my house. I'm an electrician, and have been working with the owners for the past couple of years repairing and remodeling everything electrical inside and out. There was line voltage lighting in the front of the house, but that was it. I've repaired the front yard lights, (6) 500w quartz floods and (4) 100w spots, running new pipe and wiring, but decided to go with low voltage when the owners wanted to put lights at the back of the property. The low voltage lights that I put in the back were just for walking to the trash dumpster at night and the ones in front were mainly for Christmas silhouettes that illuminated back on the house and wall, but when Christmas was over, I put in wall wash lights between shrubs and they looked so good, the owners wanted lights EVERYWHERE.

If I can get a professional like Paul to design it, I can put it in. I've emailed Paul personally asking for prices, but haven't heard back yet. I'm sure he could do wonders with this house, the 10 foot walls, the 35 foot palm trees, the waterfall by the pool, 3 water fountains and the other shrubbery in the front and back yards. But I'll have to get a price first. Hopefully he will email back or reply here.

But for sure I've learned that this is way over my head, at least to do a first class job, so I'll leave it to a pro to design it.

Next time I talk to the owners, I'm sure they will have more ideas of where they want some lighting, and I know they will be excited.

05-13-2008, 07:33 AM
Sounds good Im sure He can help you with a design. Also dont forget several great lighting companies have a strong refferal program as well.

6 500w quarts????? EEEEEK Is this the midland odessa airport or a residence ???

05-13-2008, 12:42 PM
Yeah! The original owner was very proud of this house when it was built in 1972 and evidently wanted everyone to see it at night. It was the biggest house in Odessa back then and was a party house. Those 6 fixtures DO accept 300w lamps and are on 3 switches, so can be regulated when needed, but definitely put out some light when all 6 are on.

05-13-2008, 12:46 PM
Email? I didn't get it, try this paul@night-scenes.com . 300 watt quartz? Damn, that's a lot of light!! I look forward to the email.

06-21-2008, 02:54 AM
Well guys, I used a 2200 psi high pressure washer with a small holed head on the wand to cut the ditch and was very satisfied, although I looked like a walking caliche zombie when I was finished. I was covered in it. The sprayer cut the soft soil and hard pan very easily and whenever I came across a caliche rock, I used the spray to cut around and under the rock and it usually came flying out of the ditch. The spray would not cut through the sparse grass that was growing in a few spots, but a sharp knife did the trick.
Overall, I was pleased with the sprayer and would use it again, although I would build some sort of shield to keep from getting covered with spray and mud, and maybe use a 3600 psi. But using a ditcher was overkill and not needed. The owners were very happy with the new lights, too.
Thanks for all the help guys.

Chris J
06-21-2008, 08:25 AM
What did you do to back fill the trench since you blew all the dirt out and washed it away? I believe you can find a better way to trench. This just sounds like too big of a mess.

06-21-2008, 10:16 AM
We have a lot of caliche here as well as volcanic basalt in one part of the valley. I have always just used a ditch witch Vibratory plow with cable plough. Cuts through the cliche like nothing. The basalt, not so much.

06-21-2008, 12:44 PM
The trench was less than 1' wide and the dirt, once it got wet, just flowed up and out of the trench much like a trencher does. At least until I hit a rock. Then the wet dirt flew everywhere. To fill it back in, I used a hoe and rake like normal. Very easy. In just the places where I hit a rock I had to rob a little top soil from the surrounding area, but no problem. I will post a picture of the actual area and you will see the rocks that have come from the area and then you let me know if a trencher or vibrator would cut through them. I bet not. Some of the larger ones were placed around the home and are used like a guard rail. Cars occasionally run into them with no damage to the rock. However, the smaller ones are no problem.

David Gretzmier
06-21-2008, 09:34 PM
I thought caliche was that italian seafood salad stuff...