Electrical conduit on top of driveway.

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Mr. Kent

Member
Location
NOLA
Occupation
building maintenance
Is it prudent and within code to run an electrical conduit pipe on top of a driveway and then install a speed bump on top of the conduit?
 

Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
If you install a speed bump over the conduit, the conduit is now buried and you have to follow the burial rules. This will result in a tall speed bump.

The proper way to do this is to run the pipe under the driveway. You can dig a ditch on one side and use a pipe connected to a water hose to water bore your way through to a smaller ditch on the other side. Or you can cut and patch the driveway.
 

K8MHZ

Senior Member
Location
Michigan. It's a beautiful peninsula, I've looked
Occupation
Electrician
If you install a speed bump over the conduit, the conduit is now buried and you have to follow the burial rules. This will result in a tall speed bump.

The proper way to do this is to run the pipe under the driveway. You can dig a ditch on one side and use a pipe connected to a water hose to water bore your way through to a smaller ditch on the other side. Or you can cut and patch the driveway.
Or cut the driveway and put the speed bump over the small trench
 

Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
To be more specific, follow table 300.5. For a one or two family residential driveway, the conduit must be buried 18" except in the case of a single 120 volt, 20 amp max GFCI protected circuit, then 12". For other driveways, 24".
 

Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
What if you use RMC and leave the top 120 degrees exposed, with the speed bump butting into it on both sides? Then it's not buried. : - )

I think you may have found a loophole. Would RMC be damaged if you drove over it? What about with a garbage truck?
 

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
For _temporary_ installations you can buy 'cable ramps' that are essentially plastic speed-bumps which you pass SO cord through. These are rated to be driven over, for example this one rated for 24000 lb per axle:

I would not be surprised if someone else makes a similarly rated permanent raceway assembly.

-Jon
 

Fred B

Senior Member
Location
Upstate, NY
Occupation
Electrician
What if you use RMC and leave the top 120 degrees exposed, with the speed bump butting into it on both sides? Then it's not buried. : - )
Can you give code specifics that would allow this? Everything I've seen says 24" below driveway or roadway. I've been told reasoning behind extra depth for driveway is there is more chance of excavation and resurfacing later and the little extra depth gives a little extra protection from incidental damage during such construction.
 

oldsparky52

Senior Member
There is no statement in the NEC that allows this. That's not how the NEC works. You are allowed to do whatever you want as long as the NEC doesn't say you can't.
Does the NEC disallow installing GRC on the driveway w/out cover? When you are looking for physical protection, one method of achieving it has been to use GRC.

Asking for a friend.
 

Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
The purpose of the cover requirements is to protect the pipe from being damaged by someone digging or rolling over it. If the pipe is above the ground i.e. visible, there is no concern for someone digging, but the pipe must then be physically protected from damage. It's acceptable to run pipe laying on the ground if there is no danger of it being damaged. I have run pipe on the ground under house trailers and zip-tied a couple of inches above the ground to chain link fence.

Having the top of the pipe visible with speed bump abutting it on both sides could be argued as visible or buried. I'd have to ask an inspector before I did such a thing.
 

Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
Does the NEC disallow installing GRC on the driveway w/out cover? When you are looking for physical protection, one method of achieving it has been to use GRC.
I asked that same question in post 8 above. (GRC=RMC). AFAIK, the NEC does not specifically prohibit running rigid over a driveway, but it does require conduit to be physically protected from damage. I personally would not do it. Even if the pipe didn't collapse from the weight of the vehicle, I suspect the threaded area would break from the stresses.

On a construction site you could do this if you stacked some wood on either side of the pipe for temporary use.
 

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
What about running conduit in a 'trench drain' or similar under surface open cavity. The conduit is not hidden underground, and is protected by the structure of the drain.
 

Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
What about running conduit in a 'trench drain' or similar under surface open cavity. The conduit is not hidden underground, and is protected by the structure of the drain.
I think that would be an acceptable solution. The pipe is both protected and visible. I think I would still check with an inspector before doing it.
 

oldsparky52

Senior Member
I think the threaded area would be okay, I just don't think you could secure it well enough to stand up to the stresses of being ran over (it would move eventually). I've never done it and would only consider it in a residential driveway (if at all).

I'm still curious, what code section would prevent it? Anyone? (I've never been a code guru and don't have a searchable version).
 

Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
Don't install speed bumps. They're ineffective against speeders and a nuisance to everybody else.

I live in a large development. Years ago a neighbor (I assume) came knocking with a petition to put speed bumps throughout the development. I declined to sign. He stormed off looking like he wanted to curse me out, but held his tongue. A few months later the bumps arrived. I hate them.
 
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