cameron said:
I currently use 12/2 wire for a 3/4 hp submersible pump ran at 490ft if I use a 1hp pump will the 12/2 wire be OK or will this hurt the pump and what will it do if anything?
Being an electrician, I will try to help clarify:
First, the total length of wiring is extremely important (one way). This run begins at the breaker and ends at the pump. You stated you had a run of 490 feet. What you are concerned with is the total voltage drop on the circuit. Normally, you want no more than a 5% volatge drop on a motor circuit.
If you go to Google and type in
Voltage Drop Calculator you will find several good calculators. In your case, a 1 HP submersible pump pulls approximately 9 amps at full load
AND a run of 490 feet of #12 wiring will yield approximately a 7% voltage drop. This isn't good! Think of it like this ......... the motor is being starved of energy. So, it isn't good for the motor and most probably will shorten its life.
Also, I am assuming you are currently using copper wiring. Aluminum wiring would be even worse yet!
Bottom line: If you are planning on switching to a 1 HP submersible you need at least #10 copper wiring and that would barely be within tolerance (but, it would be acceptable).
Personally, I would most likely choose # 8 copper for piece of mind.
Excessive voltage drop will also cause the circuit to overheat, which will create annoying breaker trippage. This in itself indicates something is wrong. Hope this is helpful!