Running A Conduit under a driveway
Gentlemen,
I’m going to put in a driveway gate, electrically operated. It’s a double-leaf gate hinged on both sides of driveway, with the two halves meeting in the middle of the driveway when it’s closed. So it has to have electrical operators on both sides of the driveway, and they have to communicate electrically so that they operate together.
There’s really no way to connect them except to pull a conduit under the driveway, at 18″ depth per local code. I much prefer to bore a hole under the driveway, rather than trench-and-patch the relatively new driveway surface and belgian block curbs. The length of the run is 15′ under the driveway.
Who has some geat ideas about how to do this. My best local tool rental place has a drill of some sort, but 15′ is too long for their equipment.
I tried to search this site, but it didn’t turn up anything. Perhaps I don’t know how to do that in the best way, because I should have thought that this had been discussed before!
Bob Chapman
Replies
have you seen the method that they use to run water lines for irrigation sprinklers under drivewyas? They put a jet nozzle on the end of rigid PVC pipe and connect the other end to a water hose and let the water flow. Seems to just ease it's way though the soil and i think I've seent he pieces at the BBs. Maybe rig something in similar fashion to some PVC conduit (the gray stuff for elect)??
Thanks John--- but what is "BBs" -- not a term that I know!
Bob
Big Box stores Lowes, Home Depot, Menards, etc). Schlagor gave some pretty good details... definitely worth a shot.
Thanks to everyone for your contributions.
Bob
Dig a hole along side the drive at the desired location - as deep as you need. Make the hole big enuff to be able to run your conduit in a straight line (close to level) as it goes under the drive. Meaning the hole will need to be wide perpendicular to the drive.
Now, using conduit or a pvc pipe, hook up a garden hose to the end, so's your conduit becomes the hose end. Then turn on the water and drill.
In a perfect world, you'd use this hose pipe inside of another, slightly larger pipe for the waste water and dirt to flow out of without eroding too much of your driveway base.
A few minutes later, you should have your length of conduit in place with no apparent effect to the drive. Unless you got's lots of rocks inhibiting your progress. Then your driveway gets sacrificed. Or you could hire a boring service.
I've done this several times. Including a 4" drain pipe for an eavestrough downspout.
Piece of cake.
Pete, That's almost exactly how we do it. You gave a good explanation, but to add a little more for the OP's benefit....
We do this frequently so we have a slightly different approach. Although you can certainly use a hose, we use a pressure washer. They actually sell heads for this purpose that you screw on to the end of a 3/8" or 1/2" pipe. The pipe sections would be long enough to go completely under your driveway. I have adaptors attached to the ends of the pipe to couple to the power washer. This method works better in gravel than a hose does. Although a hose works too if you are careful.
For the OP....what you have to do is set your conduit to grade and shove the hose or pipe into the conduit until it hits the dirt. Let the water flow as fast as possible, move the hose back and forth a little, and stop to tap the conduit a few inches at a time with a small sledge. Do not shove the hose or pipe too far into the soil or you will trap it and you won't be able to get it out. I prefer to use a larger conduit than actually required because it allows the soil to flow back out the conduit more readily than using a small conduit.
Do not use any more water than you need to open up the soil for the conduit. If you do, you could cause a problem with the road sinking in that spot.
Be patient and go a few inches at a time. It usually takes us about 10 minutes at the most to go under a driveway like yours.
We peel up the sod with a sod cutter first and then replace it after we fill the trench beside the driveway. When we are done, you would never know we were there.
You should have a go a the water jet technique, before trying something else. Probably someone will be along with the particulars shortly.
What the others said.
We just did this for some electrical work. Sandy and no rocks, though. If your conditions are tougher try contacting a well driller in your area. It's not deep and he would probably be able to do it in a jiff.
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no way to connect them except to pull a conduit under the driveway
Huh? Use some imagination!
1. simply feed from the garage down both sides of drive
2. Build a decorative arch over the driveway containing the wiring, it could say "Chapman ranch" or some such.
3. Then there are esoteric methods, such as infrared communication and charging a battery on the far side when the gate is closed, etc..
A guy I know has a pneumatically operated T-post driver that's really slick ($400 plus, he said). Even in very hard rocky ground it taps the post in like crazy. You could likely use the same tool to drive a pipe horizontally.
Of course then you'd have to buy a new tool which you might not use later. Depending on where you live, you may be able to rent a post driver.
I've also seen wire run (perhaps not to code!) through a cut made in the top of the concrete, then sealed over with some sort of gooey stuff.
Most of the horse farms around here have that cut for the wires that signal the exit opening when leaving..iow, like a traffic trigger that senses when a car passes over.
They also either have a Keypad, an intercom, or a remote like a garage door..or a combination of all three, to get in. And some are set where you just pull yer car's nose up close enough, and it auto opens ( handy for UPS, and the FireTrucks).Spheramid Enterprises Architectural Woodworks
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Thanks. That's another new idea for me!
Bob
I've seen utility guys use a hydraulic ram, with sections of smooth steel pipe being driven, then the ram reverses and pulls the flexible conduit/pipe back through.
(Note that this is a small, hand-operated ram, not one of the big rigs you frequently see used for major utility work.)
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Edited 11/15/2008 4:44 pm by DanH
I've retro'd a coupla powered gates.
They were all low voltage.
Don't know that you really need to be 18" below grade for low voltage.
That is something you would have to ask about for your location.
There are some great responces here already.
If for some reason they don't work - Outside the box would say to not try to patch to match, make a highlight strip to accentuate the addition of the gate.
.02
Thanks for your response. My BI was pretty clear that I needed to be down 18", though perhaps I didn't specify that it was low-voltage. He was worried about mechanical damage, of course.
Your idea about an accent strip is a good one --- perhaps my "last resort" if I can't achieve what I'm aiming for!
Bob
Per 08 National Electrical Code:
Table 300.5Residential driveways, parking areas used only for dwelling related purposes18” for direct burial and all types of conduit listed for direct burial.The exception to this is resi circuits 120volts or less, 20amps or less and GFCI protected can be 12”.Good to check with your local codes though.Nobody gets in to see the wizard...not nobody...not no how!
Don't forget that you need high voltage to both openers and that usually comes from one side of the drive and goes under the drive to the other side.
Not on the gates I have installed, all low voltage.
Line voltage only to charge the battery.
... and on the ones that I intend to install.