find a buried wire

[stevo wis]

Hi,
I am going to hook up a hot tub on one side of a porch. There was a tub before I bought the place, which had a 60 amp circuit buried under the porch and I think runs to just about where we need it. There is a disconnect one one side of the porch where the cable goes into a conduit and under the porch. I can power the breaker and disconnect, but I dont know where the rest of the cable is buried under the porch.
I could crawl under the porch and dig down to find it, but it will be a job. Does anyone have an idea of how to to find the end of the cable without so much digging?
Thanks,

Stevo

[Paul F Franklin]

You may find a local rental yard that has an underground cable locator for rent, but in my experience they are rare. If your cable isn't buried real deep you may be able to locate it (approximately) with that. It may be easier just to run a new cable (and when you do that, you will find the old cable )

[Steve Rozmiarek]

You can rent a locator, or just pay an electrician to locate it with their machine. It's probably not deep, you can also kill the power and gently use a probe to see if you can find the conduit. The probe won't work around rocks though.

[John K Jordan]

You can rent a locator, or just pay an electrician to locate it with their machine. It's probably not deep, you can also kill the power and gently use a probe to see if you can find the conduit. The probe won't work around rocks though.

I bought a locator from a local electronics house for a few hundred dollars. It uses a tone to locate the cable while swinging a pickup coil over the ground. You have to clip a transmitter to one of the conductors on one end. Not nearly as sensitive as the $5000 locators but worked where I needed it. I know it works with direct burial romex installed in plastic conduit which should be what's buried.

But that, or even a professional locator service, will need some working space above the ground, perhaps not possible with the porch described.

Also, if you can reach the approximate area, a high-quality metal detector might find the cable and let you trace the end.
If you can dig a short distance from where the conduit goes into the ground and find where it goes horizontal you might get a good idea of the direction. Unless there are obstructions or some other reason not to, underground conduit is usually run in a straight line to minimize the cost and make pulling the wire easier.

It might be easier to disconnect and ignore the old line and run a new one in conduit fastened to the joists up underneath the porch (without burying it). Depending on how the construction it might even be possible to remove a few boards and access everything from above.

JKJ

[Tom M King]

First try would just be to take something like a hoe or trowel, and scratch the top off the ground in a line under the porch. The dirt where the trench was dug will be different, at least in texture just by exposing the top of the ground. It will be softer than the surrounding dirt.

We once looked for a line at a friend's house. He was "sure" where it was, but after digging several test holes, I finally used the tractor bucket to drag all the stone off a section of driveway. The trench was revealed. It started down the driveway, but went under the next door neighbors fence, and came back on his property at a funny angle much farther down his driveway.

Often you can see it without moving anything. The grass will grow a little bit differently over the trench than all around it, even if the surface is all on the same level. I could take pictures of several places here and show you exactly where the old trench is.

It always works like this, even if the trench is 50 years old.

[Maurice Mcmurry]

Ameren is replacing all of the gas lines in our neighborhood using trench-less horizontal boring. They have some nifty locating equipment. After they have done their best to locate delicate underground infrastructure they excavate with a pressure washer and vacuum truck to create observation holes. It has been very noisy and interesting.

[Curt Harms]

There are "call before you dig" services. They come out and mark utilities before new cables or water lines are installed for example. I have no idea if they're free or how they work. Here's something for Pennsylvania:

https://www.puc.pa.gov/pipeline-safety/pa-one-call/

[John K Jordan]

There are "call before you dig" services. They come out and mark utilities before new cables or water lines are installed for example. I have no idea if they're free or how they work. Here's something for Pennsylvania:

https://www.puc.pa.gov/pipeline-safety/pa-one-call/

I've used the national "Call before you dig" (dial 811) many times. Each state manages it for their boundaries. The service protects you from being financially responsible for digging up a utility line. If the gas, water, phone, cable, or electrical utility marks the line (guaranteed accurate to within 2') you know where not to dig. If the utility (or the locator company they hire) does NOT bother to mark the lines it's their problem if you hit something. Of course, it's another problem if you are dead from digging into a high voltage/amperage electrical line! (I have 400' of 7200v direct burial cable underground from the pole on the street to my transformer.)

Here, at least, they will not mark an secondary, in my case anything after the electrical transformer or the cable pedestal, both 150' from the house, or any of the 1500' of electrical lines or 1000' of water lines I installed on the property myself. For that you have to hire someone or do it yourself. However, I've been successful in talking the local electrical utility in coming out and marking my secondary "off the record" and I had to sign something relieving them from responsibility. They were spot on and even gave me the depth at various places. (I was digging a trench crossing the secondary to install conduit to pull new TV/internet cable.)

But again, I don't think they could have located it if it had been under a porch or deck. In fact, the last section of my secondary was under a deck and that was where they stopped.

Another thing to keep in mind - I don't think the locator services can mark underground water lines unless they were installed in metal pipe or had a conductive wire run with the pipe. I have 400' of plastic pipe for water from the street to the house and they never mark it. Also, Comcast cable typically doesn't mark - if I were to dig up either of these they will come out and fix them.

JKJ

[Maurice Mcmurry]

Our locate service will not look for or mark branch circuits. My brothers father in law knew how to use a radio to find wires. He was a Motorola dealer. I wish I had paid more attention.

How to locate a buried cable using a lawnmower and an AM radio - My Daily Smile

[Tom Bender]

I love Tom's approach.

If that doesn't get it done you might ask the previous owner what they know. They probably have pictures showing the old hot tub. Or try Google Earth.

Next, try the local building dept, if there was a permit pulled it might show the location.

It can't be so much trouble to just use your shovel. Under the porch you don't care so just dig near it.

[Tom M King]

Just scrape perpendicular to where you think the line is. I would think you're bound to cross it.

[Roger Feeley]

I have never tried this but it sounded kind of fun.
extend one conductor of the wire so you can wrap it around the spark plug wire of your lawn mower. As I recall, it only took a few turns. Get a portable AM radio and tune as low as you can go. Mess with the radio and the mower throttle till you’ve made a detector.

if you try it, let me know how it goes.

[Rollie Meyers]

Our locate service will not look for or mark branch circuits. My brothers father in law knew how to use a radio to find wires. He was a Motorola dealer. I wish I had paid more attention.

How to locate a buried cable using a lawnmower and an AM radio - My Daily Smile

They do not locate customers UG lines, That is where the customer is on their own & gets to pay for.

[John C Bush]

Our invisible dog fence quit working and the service recommended an RF device--$7 back in the Radio Shack days-- that attaches inline to the buried "antenna" wire.
You then tune in an AM radio-had to buy that as well-and track the wire looking for the break. Seems the spark plug technigue could work the same.

[Roger Feeley]

Raudio Shack…..sigh….
They lost me when an employee very confidently lectured me on the number of ohms in a watt.