Backhoe Using a Backhoe

HoggyB · Feb 25, 2004

Hi, all-

I'm getting ready to dig my trench for my utilities.

It will be either 4 or 5 feet deep, not sure yet.

How can you tell, when digging, how deep you are? Do you need an assistant? Or do you just guesstimate? Or can you tell using the boom?

Also, based on my BX23 manual, I'm figuring I'll get a 4' flat bottom at 5' of depth. Does this sound reasonable?

Hog

sandyc · Feb 25, 2004

You could get real fancy and use a laser level device but we have always just dug the trench using a tape to set the depth. After a while you will be able to judge the depth by looking at the angle of the boom at the bottom of the trench.

Good luck....don't fall in!

MarkLeininger · Feb 25, 2004

I use a water level, cheap and foolproof. You won't be able to guesstimate your depth until you've gained some experience, but for burying utilities it doesn't really matter if you're level or flat.

JerryG · Feb 25, 2004

Hoggy,
What I do the most of the time is dig down and measure a spot, then look and see where the top of the trench is on the boom when it is at the bottom of the trench. You can stay pretty close this way. I still spot check once in a while.

rbargeron · Feb 25, 2004

Which utilities are you burying? Gas? Water? Sewer? Phone? Cable? Electric? I only ask because I put elctricity, phone and cable into a ditch - only needed to be 2' deep.

Jimbrown · Feb 25, 2004

Do not know where you are or what kind of dirt you are digging but here in southern Arizona a 5ft hole is difficult with a BX and I would guess more like 2 ft of flat bottom at that depth. It would take you all day to dig a 50 ft trench.

HoggyB · Feb 25, 2004

( Which utilities are you burying? Gas? Water? Sewer? Phone? Cable? Electric? I only ask because I put elctricity, phone and cable into a ditch - only needed to be 2' deep.

)

I'll be putting in electricity and telco in separate conduits and they have to be separated by 12" of (vertical) fill.

I'm also planning on adding a third conduit for future use. That may require a 5' ditch, although I'm thinking that I might be able to get away with minimal depth on the third conduit, since I will be pouring concrete over the whole thing.

Hog

HoggyB · Feb 25, 2004

( Do not know where you are or what kind of dirt you are digging but here in southern Arizona a 5ft hole is difficult with a BX and I would guess more like 2 ft of flat bottom at that depth. It would take you all day to dig a 50 ft trench. )

The dirt is mostly decomposed granite. It should be nice and damp from all the rain we've had.

I'm really hoping to keep the trench to 4 feet of depth.

Hog

rbargeron · Feb 25, 2004

In western MA the electric cable (220v from a can on the pole)was direct burial with conduit only down the pole and for the first 10 feet underground - the phone company wanted 12" separation but was ok with lateral. They wanted their own conduit (2" pvc was fine) I put the tv cable in a second pvc conduit right beside the phone one. It's been in about 5 yrs - everything is fine. About 350' long. Only 24" deep (some places maybe only 20") They recommmend deeper if there is a lot of activity over it like a herd of cows on it every day.

HoggyB · Feb 26, 2004

( In western MA the electric cable (220v from a can on the pole)was direct burial with conduit only down the pole and for the first 10 feet underground - the phone company wanted 12" separation but was ok with lateral. They wanted their own conduit (2" pvc was fine) I put the tv cable in a second pvc conduit right beside the phone one. It's been in about 5 yrs - everything is fine. About 350' long. Only 24" deep (some places maybe only 20") They recommmend deeper if there is a lot of activity over it like a herd of cows on it every day. )

Man, I can't believe that. My dad lives in NC and they did the same thing for him, direct burial from the street. It was a run of only about 100', though, so I don't know if that makes a difference.

My local power company wants 3" conduit all the way. I think I could get away with a 12" lateral separation for my telco also, but my BX23 won't dig that wide a trench, so I'm going for a 12" vertical separation.

That means a trench about 3 1/2 to 4 feet deep.

Hog

Junkman · Feb 26, 2004

Hole depth is important, because usually they want the PVC to be on a bed of sand. When I dug my trench, they all could be along side of each other, but the phone company wanted a 3" conduit. I said, no way and put in a 2". The cable is also 2" and electrical 3". I also ran 2 additional 2" conduits for the future of anything else that I might want to do. Use a weather head at the top of the conduits where they come up the pole, because this will keep water out of the conduit if installed properly. Many times they will stuff the conduit with clay and skip the weather-head. I provided them for all the utilities and they used them when doing the installation. You also have to install the pull rope when you install the conduit. If you need directions on how to do this aspect, let me know. I have an easy way....

Dave___in___CT · Feb 26, 2004

Hi...

Proper depth is important in areas were the ground freezes... wanna' be BELOW the deepest frost... otherwise... the frost can heave the cable/conduit on break it...

Dave...

rbargeron · Feb 26, 2004

I've found that if the big rocks are kept out of the backfill, PVC conduit in a shallow trench will survive frost motion. Regarding a pull string, I connected a shop vac at one end of the conduit. At the other end I wadded up a plastic bag, tied the pull string around it and dropped it into the conduit. WHOOOOOOP and the string was installed ! /forums/images/graemlins/cool.gif (only tested to 300' but will work for any length if the conduit joints are decent).

On the subject of trench width, a 12" bucket digs about a 14" ditch - close enough if you lay the conduits at the sides. Hold the conduits apart as you pour sand in between them. If its a neat job, the inspector probably won't get heartburn over an inch or two.

HoggyB · Feb 26, 2004

( You also have to install the pull rope when you install the conduit. If you need directions on how to do this aspect, let me know. I have an easy way.... )

What's your trick? We have to install 3/8" poly.

I was planning on getting a fishtape and pulling it through 20' at a time as I glued the conduit. Of course with this technique, you have to worry about glueing the pull rope to the conduit (at least I do, I go heavy on the glue).

I could use the "trashbag" technique too, which I've used before. That actually might be easier, upon reflection. I guess my fear is that it WOULDN'T work and then I'd be stuck with 150' runs and no way to get a string through. I need to stay optimisitic.

So what's your trick? I always like to learn an easier way to do something and I hate to re-invent the wheel.

Hog

rbargeron · Feb 26, 2004

3/8" poly rope will go in just fine with a shop vac. You can wait until way after the glue dries - even after you backfill. If you want to spend 3 or 4 bucks there is a commercial plastic "pig" for 2" pvc that's sold at electric supply places. The steady pull of the shop vac will unwind rope from a reel or string from a spool. You'll be happy with how well it works.

HoggyB · Feb 27, 2004

( 3/8" poly rope will go in just fine with a shop vac. You can wait until way after the glue dries - even after you backfill. If you want to spend 3 or 4 bucks there is a commercial plastic "pig" for 2" pvc that's sold at electric supply places. The steady pull of the shop vac will unwind rope from a reel or string from a spool. You'll be happy with how well it works. )

Ok, I just looked at the diagram provided by the electric company, and the first run to the transformer is 410 feet!!!!

Will the trashback/vacuum method work at this distance? I'm going to Costco this weekend and was thinking about getting a new wet/dry vac anyway. Would that do the trick? Or do I need super mondo sized vac?

Hog

rbargeron · Feb 27, 2004

You don't need anything special. Even a small shop vac is enough. It's really surprising how hard a 2" air line will pull. Mine was really more like 350' and the steady pull force was probably 3-4 pounds, even with a crude plastic pig. A better fitting pig would pull even harder. The pig should be light weight, smooth, and have maybe 1/8" clearance or less. The commercial ones have a screw eye in one end for the pull rope. Be careful not to get a ton of solvent glue in the conduit joints. Best to just coat the outside of the male section so it doesn't plow up a puddle inside the bell. Then twist as it goes in to get a good seal.

HoggyB · Feb 27, 2004

( You don't need anything special. Even a small shop vac is enough. )

OK- You've sold me. Feeding the rope through as we go sounds like a frustrating PITA anyway.

Speaking of pigs, would a real live oinker work better? The guy up the road has a litter of piglets. I could probably get one cheap.

Hog

rbargeron · Feb 27, 2004

/forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gifWhat a picture!!!!!