pressure switch wire

My well is located 400+ feet from the storage tanks and pressure switch in
the basement. I buried a 12-2 romex with the pipe 22 years ago. This spring
one of the wires shorted so I made a bastard hookup up using the ground and
the remaining good wire. Today the second one shorted, so I made a double
bastard - hot from power in house to one of the wires and cut the other two
loose. Pick up a ground at the well. Works for today, need to put on high
priority to repair.
Using underground romex again will push $150. Wire has gotten spendy. I see
underground irrigation cable in McMaster Carr #8045k11 that's rated for 30
volt. My question, would a 24 VAC supply in the basement powering 24 volt
relay at the well contactor be a reliable setup? As in last 20 years? This
would save $ on wire and I wouldn't have to bury it more than 6 inches deep.
other ideas?
Reply to
Karl Townsend
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Karl
You can find the cable/wire on Ebay for less than 150. And use water pipe for conduit. But all this is not to code so beware the code inspectors if this is a problem.
Reply to
Bob AZ
I'm puzzled. How are you planning to get power to the pump (110v or 220v) from the house to the well. I'm assuming you are dealing with a submersible pump in the well. Maybe a little more info would help. Paul
Reply to
Paul
Power goes out on #4 underground direct from the meter. This is just the signal from the pressure switch to the motor contactor
karl
Reply to
Karl Townsend
I read your explanation downthread that this is only a control line. I believe that your idea will work, but I would feel more secure installing 1/2" minimum conduit so that you can easily fix any future problems, and then use ordinary THHN conductors. Sorry, I haven't saved you any money, but you have discovered why I don't dirrect bury electrical cable. Conduit can be expensive, but it is cheap compared to the price/labor of digging a new ditch.
Reply to
Vaughn Simon
I'm missing that as well.
For all things underground, the answer is *always* conduit. Run appropriately sized PVC conduit, I'd probably say 1" would do, and pull individual THHN conductors through it.
If you have power at the well head from some other source, then just a low voltage control signal would work, or you could relocate the pressure switch to the well house.
Reply to
Pete C.
Well, I already have a stock of THHN wire from an auction. And a large supply of 1/2 PVC pipe. So this route would be VERY cheap. Now, that conduit will eventually fill with water (all underground runs will). I'm surprised THHN would be rated for years of water and ice exposure. Is this true????
Karl
Reply to
Karl Townsend
OK, I get it now. Your idea would work, but it might be easier and simpler to move the pressure switch from the house to the well. The pressure switch really doesn't care where in the system that it's located, as long as it can sense the pressure. In the future, when running electricity underground, ALWAYS use conduit (grey PVC), then pull THWN wire through it. If you ever have a problem with the wire, it's a simple matter to replace it. Paul
Reply to
Paul
NOT true. I tried it. There is a pressure wave that will kick out a pressure switch when the pump first comes on. Then the pressure drops right off and the switch closes. result is pump rapidly cycles on/off/on/off.
I've not heard of THWN and I'm not seeing it listed in Mcmaster or grainger. Tell me more about it and where to purchase.
Karl
Reply to
Karl Townsend
If you have power out at the well, why have 800' of wire for voltage loss? Run some low voltage control circuits out there.
As the others have said: use PVC conduit so you can replace wire as required. Actually, you really want to drop in TWO conduits so you can run power in one and control in the other.
Karl Townsend wrote:
Reply to
RoyJ
You need a buffer / accumulator tank and/or flow restrictor to the pressure switch then.
Check your THHN markings, you'll in all probability find it has a multiple listing including THWN.
Reply to
Pete C.
Actually it's quite common to see the pressure switch located near the well. Often in my area, the tank and switch are both buryed underground at the well head, below the maximum freeze depth, leaving only the water line itself going from the well to the house. Then again, the soil here is VERY easy to dig in and has no rocks at all to about 6' deep. I guess it all depends on the situation where you are. As Pete said, a small accumulator tank would solve the pressure wave problem.
It's simular to THHN, except the W indicates it's suitable for damp locations. Home Depot or Lowes will be full of the stuff. Or try any electrical supply house. It's very common. Paul
Reply to
Paul
What with lightning, probably not, the little transformers get fried. I'd buy 3, so I had 2 spares. Then, you'll get your 20 years. As long as the cable is good for direct burial, and the wire sized correctly for the control circuit, there should be no problem. This
Well, maybe. Rodents and all sorts of things are constantly digging at that depth.
Jon
Reply to
Jon Elson
Put in a pulse chamber made of scrap pipe, or even PVC
Political Correctness is a doctrine fostered by a delusional, illogical liberal minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.
Reply to
Gunner Asch
You do not want to install direct buried cable again, you just found out it goes bad.
You say you have a stock of #12 or #14 THHN building wire, that is also rated THHN for water immersion.
Dig your trench, and drop in two or three runs of grey PVC electrical conduit. For three or four #12 (including a ground) you only need 1/2", but 3/4" gives you room. And you should never go more than 200' without a junction box or handhole in mid run, because the longest fishtapes start out as 240' long. (And they tend to get a bit shorter over time...)
If the #4 well power feed is also direct buried put in a 2" conduit along with the signal pipe, for /when/ that goes bad. (Not if.)
Or the simple and really cheap solution: Put the pressure switch out at the well. The wonderful thing about water is that the pressure rises in the entire system at the same time, doesn't matter that the pressure tanks are remote from the well.
The only time you really need to rig a remote switch is if you have an open storage tank at the top of the hill (pressure by gravity) and a reverse acting float switch to stop the pump. Stopping the pump on system pressure would need a REALLY sensitive pressure switch, and still lead to occasional tank overflows.
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Reply to
Bruce L. Bergman
OK, everybody, you sold me. I'm going to go ahead and replace both the power wire and the signal wire in conduit at this time. My ONLY reason is Milady turns from her normal saintly self into Mrs. Hyde when there's no water in the house. And, its *SURE* to break either in mid-winter or during harvest season. Lord willing, I hope to live here another 22 years.
Question 1: The well is 5 horse and 450 feet from the main circuit panel. What size wire is needed? Both for power and the signal wire. Does the power ground need to be as large as the two main conductors?
Question 2: Is there any problem with using 100' black plastic coils of water pipe for the conduit? I have a bunch going to waste.
Karl
Reply to
Karl Townsend
For the power wire you need BIG wire to avoid voltage drop and keep the pump motor happy for a long time - but there are a few other questions before I can answer. Is the pump 240V or 480V? 1Ph or 3PH? FLA? How deep is the pump, and did they oversize that line?
This is one of the few times I will say to go with aluminum wire, because even though you have to oversize it yet another couple of gauges the stuff costs a whole lot less. And because they probably did not oversize the leads from the control box down to the pump, you want "ridiculous overkill" going from the panel to the wellhead.
And you can go a lot smaller on the ground (two gauges under the normal conductor size, not counting voltage drop) since it doesn't carry current under normal conditions - it only has to carry fault current long enough to trip the breaker. And the well casing is a huge ground rod, so if everything is bonded together properly there is another good ground at the far end.
If the signal wires are running at 120/240V from the same supply panel (but a different breaker!) you can run them in the same conduit as the power leads, and the #12 THHN/THWN/MTW would be fine for that. You are only pushing 1/4 amp to pull up the contactor at the far end.
Yes, there is a problem - mis-identification of services that could have a FATAL outcome. You decide you need to make a tap to irrigate a new row of trees, and you (or a farm hand) dig up a promising looking black poly water line that you think is an irrigation line, Get out the Sawzall and chop it in two... >_<
But the grey PVC conduit makes them stop and think "Hey, this isn't a water pipe - it's the wrong color. Water pipes are white..."
The ONLY time I'd use water pipe for something else is for low voltage services like security cameras, telephone, data, etc. And either spray paint it before you bury it or put the "Caution Buried Telephone Line Below" flagging tape above it in the trench. Or both.
So when they find the orange pipe or the flagging tape, they think.
One other use would be to pull through the 1/2" size Poly pipe as a "sub-duct" for the control wires, when you pull the 2/0 AL power wires through the 4" grey PVC power conduit. Then you can replace the #12 wire later if it goes bad or you need more leads, without getting stuck between the big wires.
If it's inside the grey conduit, external ID is not a problem.
And run pull rope through at the same time, for the same reason - you can't get a fish tape through later (with wires in the conduit) to replace bad signal wires without a hell of a fight. Without a rope you have to pull it all out and all back in.
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Reply to
Bruce L. Bergman
Its a 240 volt 1 phase 5 hp. pump. Three #8 wires down the hole 180 feet. Don't know what you mean by FLA. This pump, like all submersibles, is sort of a 2 1/2 phase unit with the control box putting some capacitance and power on the third leg. So, what size AL wire and ground? How big a conduit will I need?
One more question, what size motor contactor?
Thanks for all your help.
Karl
Reply to
Karl Townsend
FLA = Full Load Amps, often abbreviated that way on the nameplate.
It's a single phase, capacitor start unit, with the capacitor remoted topside from the motor. Starting capacitors fail with some regularity, and putting them up top saves pulling the pump for a cap replacement.
Reply to
Pete C.
No readable nameplate left on this unit that was installed in 1983.
Clamp a-meter gives 22 amps on each leg for normal run. Open up a two inch line wide open and draw goes to 26 amps on each leg. Unit is protected by 30 amp fuses at the well head that I have never replaced.
NOTE: It sounds to me like it maybe uses Sears size horses. A real 5 hp. would take more current than this.
Karl
Reply to
Karl Townsend

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