do rocks damage trenchers?

[rogerL1961]

I have some land i need to put in 300 feet or so of water line and electric power.

I have several questions. Do Rocks damage trenchers?

Can trenchers handle rocks at all?

I know nothing about this.

Does anyone know how deep i have to bury my water line in arizona. It hardly ever freezes here and when it does the waterpipes outside don't freeze even when they are not covered.

Do i have to run seperate ditches for a water pipe and an electrical pipe? or can they be put in the same ditch?

 

[brain55]

What kind of rocks are we talking about? For 300 feet, I hope you are planning on renting. Your local full service rental yard should have a good idea of the local ground conditions and what it will take to trench through it.

Brian

 

[rogerL1961]

well most of them are river rocks. inter dispersed with dirt. some of them are small like 6 inches wide and then others are a foot wide.

 

[brain55]

I wouldn't say damage as much as accelerate wear. You will definitely want a digging chain set up with carbide rock teeth. It is probably won't cut through them as much as dig them up and move them. If at all possible I would consider a ride-on machine over a walk-behind for this type of work. The ride-on will have the power you will want and be built stronger to handle the job with less chance of damage.

Brian

 

[rogerL1961]

thanks , that is what i was looking for. Now to go see what they have at the local home depot or rental yard.

 

[2458n]

Have used a number of trenchers large and small. A normal sized rental trencher will have cutting teeth like a chainsaw. These teeth are held on with two bolts in most cases. Hitting rocks will cause these teeth to be knocked off. Much like the chainsaw the trencher is going to kick around alot when running into rocks. The local rental yard can advise. Since you are running water and electric they can be ran in the same trench. If there are sharp rocks in the area make sure you backfill with clean dirt or sand. The temperature is in your favor, but by going deeper you lessen the chance of damage at a later date.

 

[brain55]

I don't consider Home Depot a full service rental yard. If this is normal terrain for your area a real rental yard will have a machine properly set-up for what you are doing. Home Depot will have something set up for doing lawn irrigation. Plus if you tell them what you are looking for it is very likely their eyes will glaze over and have no idea what you really need.

Brian

 

[beeforty]

I too had several runs of 300 ft. for water , electric and gas to diferent areas. Started of with walk behind and I didn't have to many rocks but but ground has dried clay/sand was as hard as rocks. Ended up going back to get a Bobcat rider trencher. Not a skid steer machine, dedicated trencher, just rev up to trench RPM lower boom to depth you want and eaase the hydraulic speed control forward. If the boom don't raise up go a little faster. Ocasional rocks just raise the boom or hang on for a wild ride. I had more tree roots to go back and dig by hand than rocks. Did almost a 1000' in a combination of trenches and still only payed for 1/2 day.

 

[Craig Clayton]

Your National Electric Code will define how deep to bury your electrical conduit. Your water line might have some local guide lines as to the installation. Depending on the denisty of the 6" rocks it could be a rough ride. A backhoe might be slower but that will be determined by the rocks, a trencher is the fastest if there are not many rocks.
Craig Clayton

 

[Craig Clayton]

I thought about it somemore and here goes. If you bury your water line and hydro in a 16" wide trench dug with a Backhoe and backfill with sand. Now you bury them at the same depth ie Electric Code depth but side by side.And the general rule for telephone lines are 12" above the Hydro in the same trench. If either ever fail then you dig down to just above them and hand shovel the sand out. If you bury them in a narrow trench one above the other and the bottom one fails you get to tear out both lines and or telephone line also. The telephone line can lay beside the water line in a 16" trench.
Craig Clayton

 

[Qapla]

When some here the word "backhoe" they think of a large tractor with a front-end loader and a backhoe. However, there is also a "mini-excavator" that most good rental places should have.

These hoes are on tracks and are relatively narrow. They dig quite well and are fairly easy to operate. The can dig to a depth of 7', so digging to "code" would not be a problem since most codes seldom exceed 4'.

The idea of placing the lines side-by-side is markedly more desirable then one on top of the other.

Mini-excavators come with a variety of bucket sizes. You could use a 9", 12" or 16" to dig the ditch you are after. The hoe will also be better able to move those rocks. Backfilling with sand or dirt without the rocks makes sense. However, keep in mind that if it is 15-20 years before you need to dig that line back up, there WILL be rocks down there.

I will also add, I have worked for many years using a variety of trenchers and hoes. We have a "saw" type trencher, a Vibra-plow (pipe puller), chain trencher and a mini-excavator as well as a tractor backhoe. If I were digging the line you want, I would choose the mini-e.

 

[rogerL1961]

i appreciate everyones input. I think I will use the Mini E and at the same time dig a footing for a block fence.

is there a book for arizona that has the building codes? Does Home Depot have a book like this?

 

[whistlepig]

Best to talk to the county or city inspector. Which ever prevails in your area. We don't live in in city limits here so the county prevails. If you live in the city limits the city would prevail. The inspector is going to be the guy that says yes or no. Best to make him happy. Talking to a local contractor would be a good start.