Replacement Switch for Well Water Motor

Discussion in 'General Electronics Chat' started by CircuitGuy23, Jun 3, 2018.

  1. CircuitGuy23

    Thread Starter New Member

    Jun 3, 2018
    2
    0
    Hi everyone,

    I recently moved into an older home that has well water and a 1/2 HP 230VAC (single phase) motor. I would like to replace the breaker box/switch for increased reliability. It currently has a Square D 30 Amp enclosed, single throw switch, 240 VAC with two 20A NON-time delay fuses. I've had to replace the fuses a couple of times already (due to power surge/overloaded circuit) and would prefer not to need to keep them in stock. What is the best alternative or can I just replace it with a 240V safety switch? There is another 30AMP breaker for this circuit at the main panel.

    Thank you for your input!
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
    16,194
    4,742
    20amp fuses seem a little high for a 1/2hp motor on 24ov.
    You could use a NFB (non fused breaker) for a local switch, you may be able to install it in the fused disconnect with a little modification.
    Max.
     
  3. WBahn

    Moderator

    Mar 31, 2012
    23,092
    6,942
    My well breaker box has 20 A slow-blow fuses in it. You might check to see if that is an option for you. But the fuse blowing problem might also be a symptom of impending pump failure, too. So you might want to plan ahead for the possible need to replace the pump.
     
  4. CircuitGuy23

    Thread Starter New Member

    Jun 3, 2018
    2
    0
    Thank you both for the quick replies. The first time it blew was due to me plugging in two 1500W heaters in the garage which I found out is on the same circuit. I'm going to have my electrician run a dedicated circuit. This last time I am wondering if it was due to cheap fuses? I replaced both fuses with Bussman "general purpose" cartridges. I'd like to get a more reliable solution and wonder if I need the fuses when there is already a 30A breaker at the main panel? Thanks again.
     
  5. MisterBill2

    Well-Known Member

    Jan 23, 2018
    1,523
    269
    A well pump should be on it's own circuit, certainly. And an interesting thing is that a slightly bad connection can lead to excessive motor current, causing a fuse or breaker to trip. One simple diagnostic thing would be to remove the fuses and measure the resistance to ground of the motor circuit. Then record that resistance value. Then, if the fuses fail or the breaker trips in the future, measure again, with the power off. A drop in resistance to ground indicates an approaching problem. This is an easy trick that can be used with any hard-to-reach motors. Just be sure that the electrical power is completely off before connecting the ohm meter.
     
  6. MaxHeadRoom

    Expert

    Jul 18, 2013
    16,194
    4,742
    If it blew the fuses rather than a 30amp breaker then it save something, you can get all grades of fuses, including time delay.
    As previous, 30amp is a bit high for a 1/2hp pump, especially on 240v.!
    Max.
     
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