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I am trying to install a pressure tank and have a question. The pump wire coming into the house from the well has three wires: red, black, and yellow. There is no ground. It seems to be a three-wire pump, but there is no control box and the red wire is capped. It was just wired to the pressure switch as if it is a two-wire pump. It seems to me that the wire from the well is missing a ground, and that maybe the pump was wired completely wrong. Any thoughts? Thanks in advance.
-Kevin Conrad
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Replies
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Kevin,
I'm not an electrician but I think the 2 wire pumps have the capacitor bank built into the pump itself. This would have to be your situation if it goes straight to the pressure switch. The red wire is normally used as the starting wire from a typical control box. This is switched off by circuitry in the control box when the motor starts. It sounds like the installer just used the 3 wire cable just because he had alot of it or something, then capped off the red wire. I would think you would still need your green ground wire whether its a two or three wire system.
*Darrell: Doesn't a well filled with water make a pretty good ground?I don't do well water, but I seem to recall that ground cables to the pump were not included, at least in older systems. Perhaps the newer code requires them.
*John, Yeah, I think the metal casing is a pretty good ground. My electrician fastened the green wire to it. I think only the Yellow, Red and Black go down to the pump. Maybe an electrician on the FHB list can get us all straight.
*Kevin; I have the Water Ace pump instructions in front of me at this moment;we are about to install the system tomorrow. Thier two wire pumps diagram simply shows two wires going from the pump directly to the load side of the pressure switch;The pressure switch then connects to the fused disconnect or breakers.No capacitor is shown for that two wire pump,nor does the diagram show color coding of the wires. The three wire pump diagram illustrates three wires going to their Water Ace motor control panel.This panel contains the capacitor and those three wires are labeled R for the start windings,and B and Y for the run windings of the pump.The motor control panel is then wired to a pressure switch and /or breakers or disconnect.I donot have the pump here to confirm that R,B,andY are red,black and yellow respectively. I am getting ready to post a question of my own.The instructions for both pump types call for a pump motor grounding wire but the diagrams do not show it.Does the ground have to be grounded at the breaker box or can it be grounded near the well head using a standard copper coated grounding rod?And how should the ground be connected to the pump? Good luck Don Lauer
*I am thinking most pumps are 220v thats why you got 3 wires, but the yellow instead of white is a mystery.
*O.K., here's some info on grounding, and why a well casing, although at earth potential, will NOT do the job as a ground for an electrical system unless it is electrically connected to the electrical system's ground bar.There are two wires in your typical grounded electrical system that are connected to earth (zero) potential: the grounded conductor (AKA the neutral) and the equipment grounding conductor (AKA the ground).In 240/120 volt systems, the neutral is the return or the low potential conductor. It carries the electrons back to the source after they've unloaded their energy at the motor, light, or whatever.The equipment grounding conductor EGC (green or bare copper "ground" wire) is sort of an "overflow" pipe; it's there to act as the path for current that gets out of hand. Here's how it works: the EGC is connected to the metal housing of appliances, tools, light fixtures, etc. That EGC is (or should be) solidly connected back to the electrical panel. If there's major electricity leakage from a frayed or broken internal wire to the metal housing, the EGC carries it back to the panel---and what you have is a short circuit. That causes the breaker to open, hopefully before the leakage has created a hazard to someone picking up the tool or touching the fixture or appliance.So for that ground wire to offer any protection against electrocution, there must be a solid electrical path back to where the circuit starts (the electrical panel or subpanel). Something is not really "grounded" from an electrical system sense unless it's solidly connected to the ground bar in the panel. Just being at earth potential is not enough to trip the breaker; the earth will not carry enough current to pop the breaker.Now, a well casing is a good grounding electrode; but it's a grounding electrode only if it's connected to the panel ground busbar.Metal water pipes and gas pipes in a house also have to be connected to the ground bar in the panel, but not because they are acting as a ground potential source...they're connected because we want them to be at zero potential, just in case a hot wire (meaning hot or neutral) wire comes in contact with them. In which case, Bang! The CB opens. Connecting something to the ground bar (and therefore earth potential) is called "bonding".Proper bonding is important. A friend of mine was on a jobsite (a renovation) where a plumber was electrocuted while cutting out some old galv iron water pipe. Turns out it was "live" (120V) because it was accidentally in contact with some old wiring.Keep in mind that the circuit breakers job is not primarily personnel protection. A breaker can pass many milliamps (more than enough to electrocute you) pretty much continuously without tripping. But a direct fault to ground will trip a breaker. GFIs protect you against both high and low current ground faults. And they don't need an EGC to work (but they do need an EGC to test..)Get my point?
*The NEC was changed just a few years ago to require a separate "grounding" conductor for submersiable pumps. As usual, either a green or bare Cu wire is used. Also, the metal well casing must also be bonded to the equipment grounding system. Older installations will not have this additional grounding wire. Articles 250-112(l) & 250-112(m).Red, Black, Yellow are the standard colors for motors with external capacitor-start control boxes (a good idea, since the capacitors go out more often than the pump motor itself does). Have you verified this pump actually works with the present wiring?
*Cliff, That is really an excellent reply! You have explained in simple terms, a rather complicated and often misunderstood subject.
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I am trying to install a pressure tank and have a question. The pump wire coming into the house from the well has three wires: red, black, and yellow. There is no ground. It seems to be a three-wire pump, but there is no control box and the red wire is capped. It was just wired to the pressure switch as if it is a two-wire pump. It seems to me that the wire from the well is missing a ground, and that maybe the pump was wired completely wrong. Any thoughts? Thanks in advance.
-Kevin Conrad