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I'm looking for help locating an unused electric power cable. When I bought my house I was told that there was a circuit in place and a switch for operating an electric gate. I live in the country and my driveway is pretty long, the logical location for the gate is maybe 500' from my front door. There is a Circuit Breaker labeled 'front gate circuit' and a push button switch with no other rational use by the front door. I'm soliciting ideas for locating that unused wiring to possibly repurpose it. There used to be a gate, but never an opener. I've dug a lot of holes in that area over the years for one thing or another, never seen a direct-bury cable or electrical PVC though I've cut the phone line a time or two. Any ideas for confirming its existence and locating it? I think there would logically be some low voltage stuff for control, maybe communication, but the existence and labeling of the CB makes me think there is a power line out there somewhere. (Most gates like this use solar and a battery, so this is unusual.)

- David

First question that comes to mind is - are there wires attached to the CB? Where do they lead thee to?

JPG wrote: ↑Sun Mar 28, 2021 6:30 pm First question that comes to mind is - are there wires attached to the CB? Where do they lead thee to?

Yes, there is a wire. Only thing remarkable is that it is large for the 20A CB. Tentative estimate it is AWG 10. Other than that, looks like typical 2 conductor w/ ground Romex style. It leaves the box on a downward trajectory, so it is inside the outside wall. Texas slab construction, almost all of the wiring leads upward into the attic.

- David

DLB wrote: ↑Sun Mar 28, 2021 7:10 pm

JPG wrote: ↑Sun Mar 28, 2021 6:30 pm First question that comes to mind is - are there wires attached to the CB? Where do they lead thee to?

Yes, there is a wire. Only thing remarkable is that it is large for the 20A CB. Tentative estimate it is AWG 10. Other than that, looks like typical 2 conductor w/ ground Romex style. It leaves the box on a downward trajectory, so it is inside the outside wall. Texas slab construction, almost all of the wiring leads upward into the attic.

- David

If it truly ends 500' from the house I would expect 10 gauge wire on a 20A CB.

Wire gauge for a given circuit is based on nominal current draw AND acceptable voltage drop for wire length (typically <3% voltage drop is required for branch circuits). At 500 feet that is a long pull so I am sure the electrician was trying to minimize voltage drop and selected 10AWG from this. If you want to do this yourself the cheapest first level attempt could be to use a tone sounder. Just go to Amazon and search for "Fox and Hound Tracer" and you should find multiple brands and price ranges for this. To use you disconnect the circuit from the CB and attach the tone generator to the cable (be careful not to short anything out in the panel while doing this). Then you take the receiver and go down to the gate area and walk around with this receiver near the ground. When you get near the cable you should hear the tone and can localize where it is coming from to close in. Depending on how far below ground this is you may or may not find it with this method. Also this will only work if the cable is direct burial and/or in PVC conduit. IF it is EMT conduit then you might as well just use a metal detector instead to find it. A next level up is a more expensive RF tracer but you might as well hire someone to use it cost wise. Good luck.

A warning...IF at the end (near gate) the wires are shorted together when installed (because it is for future use) then the tone sounder method won't work.

I think I can visually confirm the conduit type, I may need to cut a small access hole in some sheet rock. But one thing I thought of this morning is troubling. Several years ago I put in a water line for my wife's garden that had to cross the path of this wire and I trenched about 30" IIRC. The only way I can think I missed this wire is if it was buried deeper than I trenched. That seems unlikely and probably would put it beyond the range of these tracers unless they brought it near the surface at the gate end. Utilities to the house were marked when I trenched, but this would not have been. To me it seems likely I would have run into this wire but unlikely I wouldn't know it. I guess if I cut it the tracer may locate that for me, I know where my water line is... It's also hard to rationalize: If true, this was not an inexpensive project the PO undertook, the electrical work probably cost more than the part they didn't put in.

- David

I have used Fox & Hound tracers for years doing my own wiring in a couple of houses and they work great, but I have no experience using them at the end of 500ft so I can't say for sure it would work. The benefit is they are cheap (some are only like $20) so may be worth checking out. Here is the thing...IF they didn't run conduit all the way to the gate and terminate it on the side, etc. where you can see the conduit then this was probably because the electrical was run before anything was constructed there. They would have needed to leave some extra wire there to allow for the run to be finished after construction and it may be coiled up. This will help the receiver to find it if it is looped like this even if it is underground. I didn't want to give you false hope and I have no direct experience finding underground cable, but I know enough about the process to try to point you in the right direction. Didn't think to mention it in last post but you may want to disconnect the wires from the CB and ohm it to confirm if the wire is shorted on the end or not before attempting this.

P.S. A good metal detector can detect different types of metals so should be able to find the copper wire inside of PVC conduit or directly detect EMT conduit. Maybe you can find some place that rents these because they are kind of expensive (to get a good one) unless you use it as a hobby.

I be confused WHY an unterminated run that is connected to a live CB would be intentionally shorted?

I would be inclined to NOT connect to the CB.(the hot anyway).

Besides the CB needs to be a ground fault breaker due to exterior run.

JPG wrote: ↑Mon Mar 29, 2021 10:28 am I be confused WHY an unterminated run that is connected to a live CB would be intentionally shorted?

I would be inclined to NOT connect to the CB.(the hot anyway).

Besides the CB needs to be a ground fault breaker due to exterior run.

It shouldn't be, but keep in mind this is a non-active circuit so CB should be off irregardless. I just wanted to point out that this circuit may have been shorted together at the end by terminating it into a wire nut. Yes this would trip the breaker as soon as the homeowner flipped it on but this, by some, may be considered safer than turning on a CB and having a live wire with exposed ends sitting in the ground out in the yard somewhere. With unidentified circuits like this you really don't know what you will find until you trace them out...I was just trying to point that out. Working as an Electrician Helper as a kid I remember finding some strange things in houses that others had wired so it wouldn't surprise me if they are shorted.

Personally I would put a wire nut on each unterminated conductors individually.

I am curious re the fox/hound devices that would make hot-neut short a problem. How do they work?

Oh yes I understand the strange things one may find.