Locating under concrete floor

[480sparky]

Have an interesting problem, and may have a solution to part of it.

School has a general-purpose circuit with 6 receptacles on it in the hallway & common area. Problem is, they have 3 soda machines and a milk cooler plugged into 3 of the receps, so if anyone plugs anything else in, the 20a breaker trips. I checked amps this morning, and it was running 15.68a.

I'm pretty sure the wiring is in PVC under the slab (EMT goes down from the panel, the converts to either PVC or ridgid at the floor, can't tell which), and is 3/4" with 4 circuits in it (2 MWBCs). Assuming it is PVC (I can't imagine it's ridgid, building is only 6 years old), my guess is it's not too far down, maybe a couple inches below the slab.

But instead of pulling all the devices out of the walls (unsafe with kids around, and would need to move the machines anyway), I thought a locater would be able to track the path of the conduit so I could at least get an idea of how the circuits that are in it are run under the slab.

Has anyone every tried this? And if so, is there any 'tricks' to making it easier?

 

[iwire]

Has anyone every tried this? And if so, is there any 'tricks' to making it easier?

I have had good luck just using my amprobe circuit tracer on high, but I already had a starting point which was a big help.

I imagine the locater would be easier.

 

[chris kennedy]

Panel schedule is no help?

 

[480sparky]

I have had good luck just using my amprobe circuit tracer on high, but I already had a starting point which was a big help.

I imagine the locater would be easier.

Starting point is easy..... the electrical room where the 4 circuits originate.

Panel schedule is no help?

I know where the 6 receps are..... the original prints are quite accurate. There's no changes to the layout on the as-builts.

What I need is to find out how they are piped together, and how the other 3 circuits are passed through the layout.

I have my guesses as to how it would be piped, but that's based on how I would do it. I can't speak for the outfit that actually installed it. For all I know, the pipe runs to one of the other loads first, then to another, the third, then the 6 receps on the problem circuit last.

Edit to add:

Here's a rough layout:

The 6 receps are on circuit #1. Circuit 3 is along for the ride, as are two other circuits. So without taking everything apart to see what goes where, I was hoping to use my locator to take the place of using my x-ray glasses, which are currently in the R&D stage at my optometrist.

 

[peter]

480,
"If you gave 10 electricians that diagram, they would lay it out in 10 different ways."
Since this is underground, I would want to minimize digging. So I would first head towards receiving, then the one outside the kitchen and then the milk machine. Then maybe split with one run to the double machines and the other to run to the single soda [must be Pepsi] machine and then on to the outside one. But that's just me.
I like your drawing. It is very clear.
However, since there are three other circuits in the conduit that get dropped off along the way, I would suppose that those circuits would end up in receiving and the kitchen.
Perhaps you could just run something like a new conduit overhead.
~Peter

 

[quogueelectric]

Just open the 6 boxes it shouldnt take more than an hour and balance the load.

 

[480sparky]

....Perhaps you could just run something like a new conduit overhead.
~Peter

These are all in CMU walls.

Just open the 6 boxes it shouldnt take more than an hour and balance the load.

You gonna move the soda machines for me?

The other loads I haven't found yet. That is why I want to be able to follow the pipe under the slab.