Help: Identifying wires in garden?

So I have a set of three wires in my garden popping out of the ground in a conduit. 1 green, 1 white and 1 black.

I want to know how to determine if these wires are connected to my breaker box and if I can use one of them as a neutral to get 120v from a nearby working 240v circuit that does not have a neutral.

Using my multimeter
1. There is no voltage across any of the 3 wires
2. Hot from nearby 240V circuit to any of the 3 wires reads 120V
3. There is continuity between the green wire and the ground from the nearby 240v circuit
4. There is no continuity between the white and green wires.

Thank you for your help.

I suspect this is the old wiring for the pool pump and pool lights. I think it was 120V because the old pump was 120V. So that does mean the white wire is a neutral. But how can I tell if it is still connected to the breakerbox neutral

 

I'd start by looking for the other end of that conduit. You could also try checking your panel for a stranded neutral conductor of the size in the picture.

 

Thanks Joe, the conduit disappears under concrete about 40ft of deck. Have looked all over and cannot find where it emerges. Probably underground at the breaker box.

This is my breaker box! I am finding it hard to find anything...

Does the fact that : Hot from nearby 240V circuit to any of the 3 wires reads 120V mean that the wires go back to the breaker box.

Though if they do, then why would not be continuity between the white and the green wires

 

Not necessarily. If you were using a digital multimeter, other wires may be floating.

I suspect there may be another splice before the load center. Do you have continuity between the conduit and ground?

Also, bottom 2 breakers are wrong breakers for that panel. You should install GE breakers. You have Siemens and squire D homeline breakers there.

 

Thanks Iambition! You are bang on! The two bottom breakers are not connected to anything and have never worked and I am using a digital multimeter.

There is no continuity between the ground and the conduit.

I am not sure what you mean by "floating". Excuse my ignorance, I am engineer of a different persuasion! But how does the circuit complete if the wire does not go back to the breaker box

 

Floating means it is not connected to anything.
When a wire runs next to another wire with a current flowing, it induces some voltages. Also, the wire can complete circuit to ground through moisture in the air and soil.
The current that can flow in these situation is so small there will be no harm. But, the digital multimeter has very high internal resistance, it is capable of measuring this so called phantom voltages.
If you actually put any load, the voltage will disapear.


If you don't have continuity between ground wire and the conduit, but has continuity between this ground wire and ground wire from another circuit, your conduit is either broken (maybe rusted out?) or not installed properly. Metallic conduit should have metallic conduit and junction boxes all the way to the load center or connected to a grounded metallic junction box. Basically metallic conduit has to be grounded all the way.
Your finding increases possibility of a splice somewhere. You will actually have to trace the conduit somehow. Hope the splice is not buried.

 

Ahhh I see that makes sense. I could connect a lamp to see if it will work. The conduit disappears under the concrete within 3 ft. The deck is like 40 ft long and the breaker box is at the end of the deck so its unlikely that I will find the splice.

Perhaps, if I could explain a little more in detail...

I want to control my 2 speed pool pump (240v) with 2 smart switches. One for on/off and one for hi/low. The switches work off 120v. So the plan was to use a contactor and a relay to achieve this switching.

The pool pump is wired with only 2 hot lines and a ground no neutral.This line runs above ground except for the last 5 feet where it goes under concrete to the breaker box.

However, there is the (what I assume older) pool pump connection which is now unused. This runs entirely under the concrete for 60 ft or so. I am hoping that if one of the three wires in this run is functional and can be identified. I can connect it to the neutral bar in my switch panel and use it as a neutral to get 120v to power my smart switches.

Alternatively, can I use a 240v to 120v step down transformer to power my smart switches.

I hope this fleshes out my situation and more experienced heads can point me to a solution.

 

To the more code-knowledgeable here:
Even if those wires are traced back to the panel, I don't believe the neutral can be used since it doesn't run with the hots from the circuit. My understanding is that all current-carrying conductors need to be in the same raceway/cable to be code-compliant.

 

This will be a good option.
As Zorfdt said, you cannot have a wire run separate from rest of the wires in same circuit.
If you managed to get all wires in the conduit connected, then this can act as separate 120V circuit instead. But, you cannot use just one wire from this conduit.

 

Ugh code! But I can see how that makes sense. I guess a transformer it is. I'm guessing since the transformer only has to power the two smart switches, it wouldn't have a high wattage requirement, right?

Thanks for all the advice. I'll update when/if this finally gets done!

 

Why not just open all the breakers in your service panel, attach a 9V battery to the exposed wires and look for that dc voltage in the panel? That should identify where the cable is sourced. If the service panel is properly labeled it might even tell you what the cable was used for.

 

What kind of smart switch are you trying to use?
Getting 240V capable smart switch may be better option.

https://www.amazon.com/Sonoff-Interl...627349&sr=8-12

You can probably use this. It can take up to 250V directly or powered by 5~24V DC. It can switch up to 10A.
You might have to add 2 pole relay driven by this smart switch to properly disconnect both poles to the motor.

 

Some good ideas here, thanks so much guys! Love the 9V battery idea, its a good 70ft to the breaker hopefully that will still work. I know this was the original circuit for the pool pump, must have been abandoned for a reason, which is why I was not holding out hope for all 3 wires to function. But if the code disallows just using the neutral then that solution ends there... still worth a shot to check with the 9V.

Using 240V switches is what I first considered. Now, I am using a TP Link Kasa outdoor switch. I actually have Shelly1 switches that are also rated for 240V. But I need something rated for more than 40C. This is outdoors in Arizona... gets hot. The Shelly and the Sonoff are rated for 40C. I don't know how important that is on a "actually in practice" basis, but I was being cautious.

 

Sonoff is fairly simple device, but it might crash with pronged exposure above 40C. I don't think there will be too many smart devices that will work above 40C since most of them don't come with heat sinks. Adding heatsink to SoC and WiFi module may be enough to make it function as intended.

Another option would be running thermostat or sprinkler wire to your pool pump and install 2 relays or contactors at the pump. Then you can just install controller inside your home remotely. Low voltage wire doesn't need to be buried and sprinkler wire can be directly buried into the ground if needs to be.
You will also need a low voltage AC transformer (24V used for HVAC system will be a good choice) for the control circuit.

 

Just to wrap this up for anyone stumbling upon this. I have everything installed and working on a 220V circuit. Sonoff switches are holding good. I will update this after the summer. Fingers crossed.

 

I have another question and then a couple comments. Is this a 150 amp panel? I hope it is because 3/0 aluminum service conductors are not big enough for a 200 amp service. The Square D Homeline breaker at bottom right in the picture does not belong in a GE panel, this is a code violation.