I want to wire a well pump into my homes 200 amp breaker box using a 20 amp breaker and #12 wire?

Question

my guestion is . there is a voltage slector on the rear of the pump witch setting would i use 115 volt setting or 230 volt

Answer 1

If your pump draws 20 amps at 115 volts, it will draw 10 amps at 230 volts. As wires get longer, there is a voltage drop in the wire due to the wire resistance and the current through the wire. That means a given size wire has a maximum length depending on the current. #12 wire will carry 20 amps for about 50 ft without producing unacceptable voltage drops. By switching to 230Volts (and wiring to a 230V breaker), you can use #12 for a 100 ft. run. Any further and you will need larger wire.

Answer 2

Uncledjm was exaggerating, but he is trying hard to make you feel comfortable with what he knows the reality is. You are more than likely ok to install another 40 amp. Your main breaker will protect from exceeding 200 amps, but your main breaker isn't intended to operate to let you know whenever you may have used to much, the breaker selection is intended to protect when a fault occurs, it should be sized to never trip. When a load calculation was performed at construction it is likely that the formula produced a number less than 200 amps, probably more than 125, the next size smaller, and some area's require a minimum size of 200A anyways. Adding the numbers on the breaker handles normally exceeds the panel rating, the code has a calculation formula that recognizes load diversity. Meaning they recognize you won't heat and cool at the same time, multiple ovens will never all pull full amps, electric water tanks only heat some of the time, your dryer probably only draws 20 amps, you don't use all the receptacles on a circuit or panel at a time, and if you have multiple air conditions one will take some load off the other. A few jurisdictions that have a procedure that expect a new calculation to be performed when a permit is applied for, and the local inspector has the ability to ask for one when he inspects the installation. But all that being said, from what you described, probably gas heat and water heat, and mostly 20 amp circuits, go right ahead, plan to add another AC, your panel size isn't going to be a problem. If you have any doubts then don't let work start until an electrical permit is obtained.

Answer 3

The 230 volt setting would be more efficient as it would require less current. Your 200 Amp Breaker Box should have both 120 and 240 Volts available. A different breaker is required if you want to use 240 Volts as opposed to the breaker used for 120 Volts.

Answer 4

Use the 115 volt setting if wiring into your service entry. That is the 200 amp box you describe.

Answer 5

That probably indicates that the pump could be wired either way...The real question is how did you wire it? The 230V setting would have 2 hot wires out of phase by 180°, a neutral, and probably a safety ground. The 115V setting would require only 1 hot, 1 neutral, and 1 safety ground.

If you havn't done it yet, the 230V method is probably more energy (cost) to run, but the wire for the 115V will be cheaper, easier to get, and easier to run.

If the setting is in the incorrect position, it could have fatal effects on the pump.

Answer 6

Since there are conflicting answers, I'd like to add that Vritualguy got it right. I don't know why rscanner got a thumbs down, because he is also right, although he didn't have much detail, while it is true it makes little difference to the motor what voltage it is running at, but as Virtualguy said, there will be less loss in the supply lines at the higher voltage, so the overall system will be more efficient at the higher voltage.

Answer 7

Use the 115 volt setting. I am assuming this is a single pole circuit breaker.

Answer 8

My husband works for Chambers and Phillips in Canton, Texas.They drill water wells. They would need more info from you regarding your question, the web site is www.chambersandphillips.com. You may also contact them via telephone at 903-567-6091.