Locating conduits/circuits in concrete slab

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sw_ross

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I have a structure that is one level, slab on grade, with concret block walls. The panel, switches, receptacles, etc are flush mount with conduit run through the concrete. Probably 12-15 conduits going down out of the panel bottom, I'm assuming they go into slab and head off in various directions.

The plumbers want to cut into slab to re-route drain lines.
Whats the best way to locate the conduits to keep the plumbers from making more work for me?

Thanks!
 
Either the GC or the contractor should hire an x-ray company to perform that type of work.
 
Wow! Okay... So there's not a method to try and use a locator through concrete? (Not that I have access to a fancy locator, just curious)
 
GPR? Some sort of X-ray?...

Does anyone use/have the Ideal SureTrace? Their YouTube videos show it locating/following a circuit in a slab ( they don't give the particulars under which the demonstration is done). They say it can locate underground in parking lot (doesn't say whether it's direct burial or conduit)
 
We have a high end locator that shows depth.

We could locate conduits in this situation, but it wouldn't be as ideal as getting it x-rayed. With branch circuit conduits going all different directions under the slab, one would need to start at the panel or similar and follow every conduit to it's end to be sure it didn't zig zag back and forth into the plumbers proposed concrete cutting area. It would be a little time time consuming.

That's versus hiring an x-ray company to come out and take a look at just the areas that need to be opened up, but not having to worry about tracing conduits to see their path.

I'd say it'd depend on what your resources are in the area you're in.
 
Cow said:
We have a high end locator that shows depth.

We could locate conduits in this situation, but it wouldn't be as ideal as getting it x-rayed. With branch circuit conduits going all different directions under the slab, one would need to start at the panel or similar and follow every conduit to it's end to be sure it didn't zig zag back and forth into the plumbers proposed concrete cutting area. It would be a little time time consuming.

That's versus hiring an x-ray company to come out and take a look at just the areas that need to be opened up, but not having to worry about tracing conduits to see their path.

I'd say it'd depend on what your resources are in the area you're in.
Click to expand...

Exactly what we have done in the past, first we would layout the penetrations and they would come in and confirm that there was nothing within the area we had spray painted on the floor.
 
infinity said:
Exactly what we have done in the past, first we would layout the penetrations and they would come in and confirm that there was nothing within the area we had spray painted on the floor.
Click to expand...

Thanks, that makes sense.
Would I just google for X-ray companies in my area? What specific type of company do I look for?
 
X-ray.

I do a lot of jobs every year that require re-routing of drain lines. Now they just pay us to fix everything they cut.

You could potentially try to determine what exactly is in the slab, and see if it’s cheaper or equal to just repair it if they do cut a line.

I encounter this a lot of restaurant remodels, and typically it’s just some lot light circuits passing under the bathroom and a few receps maybe. Usually around $5k to fix.


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sw_ross said:
Does anyone use/have the Ideal SureTrace? Their YouTube videos show it locating/following a circuit in a slab ( they don't give the particulars under which the demonstration is done). They say it can locate underground in parking lot (doesn't say whether it's direct burial or conduit)
Click to expand...

I have one and it's a major pain trying to trace Romex behind drywall. I can't imagine using it on concrete with any type of success.
 
brantmacga said:
X-ray.

I do a lot of jobs every year that require re-routing of drain lines. Now they just pay us to fix everything they cut.

You could potentially try to determine what exactly is in the slab, and see if it’s cheaper or equal to just repair it if they do cut a line.

I encounter this a lot of restaurant remodels, and typically it’s just some lot light circuits passing under the bathroom and a few receps maybe. Usually around $5k to fix.


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Click to expand...
Was that $5000 to repair a cut conduit? You doin good:)
 
So far, not one of the stud finders that claims to work in concrete has been any good..not even at finding rebar. I actually have an old horseshoe magnet I picked up years ago for finding rebar, and sometimes my signal tracer works for cables..but it misses more than it finds...
 
GerryB said:
Was that $5000 to repair a cut conduit? You doin good:)
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Yeh and re-pull conductors. Like I said usually some lot lights, and it’s a pain to re-pull them. Also, it’s not like it’s something that can wait, so typically have to do a lot of shuffling to get someone there to fix it, so I’d say there’s a bit of a labor tax for that.


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Utilities use underground locators all the time. They use a clamp-on signal generator and the locator follows the signal along conductors or conduit. Not sure how it would work for embedded metallic conduit (most utility UG is in PVC and uses the conductor for the signal), but might be worth a try. You might even get a utility to loan you one and even a tech to operate it (FOR A NOMINAL FEE). :D
 
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brantmacga said:
X-ray.

I do a lot of jobs every year that require re-routing of drain lines. Now they just pay us to fix everything they cut.

You could potentially try to determine what exactly is in the slab, and see if it’s cheaper or equal to just repair it if they do cut a line.

I encounter this a lot of restaurant remodels, and typically it’s just some lot light circuits passing under the bathroom and a few receps maybe. Usually around $5k to fix.


Sent from my iPhone using Tapatalk
Click to expand...

Out of curiosity, how do you repair damage done if conduit is cut? After removing the damaged conductors, what fittings would you use to splice RMC back together?
 
sw_ross said:
Out of curiosity, how do you repair damage done if conduit is cut? After removing the damaged conductors, what fittings would you use to splice RMC back together?
Click to expand...

In my situation , it’s always PVC


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sw_ross said:
Out of curiosity, how do you repair damage done if conduit is cut? After removing the damaged conductors, what fittings would you use to splice RMC back together?
Click to expand...

Last place that a plumber drilled into a RMC the sparks flew before he cut to far thru, I was able to re-pull conductors and used backer-rod to fill the cut void in RMC and re-mortared. Not sure what you would do if they cut completely thru leaving no metallic grounding path.
 
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