garden pump tripping RCD

Discussion in 'Electricians' Talk' started by Hombrey, Jun 21, 2007.

  1. Hombrey

    Hombrey New Member

    Had a call out today, a recently installed garden pond pump supplied by socket on ring main in garage. It appears that when the pump is switched off at socket, or by plug in timer in socket, 30mA rcd trips. I tested ring main and pump cables, all appears ok. My thoughts are pump should be supplied by double pole switch, or through a timer that switches both poles, because the neutral being permanently connected, when the phase is isolated by the switch or timer, the neutral (with the pump coming to a stop) causes imbalance on RCD and trips. Anyone agree? or am i barking up the wrong tree?
  2. wklivesvtime

    wklivesvtime New Member

    wrong tree mate i think, ramp test, then change pump
  3. Hombrey

    Hombrey New Member

    did a ramp test, 28mS. You reckon shagged pump?
  4. wklivesvtime

    wklivesvtime New Member

    poss, i know i would get it swapped before i spent ages fecking about trying to solve what might be causing it
  5. wklivesvtime

    wklivesvtime New Member

    obviously checking the obvious first.
  6. Hombrey

    Hombrey New Member

    not 28mS but 28mA.... before i get a ribbing
  7. Hombrey

    Hombrey New Member

    will have another look at pump, when bloody rain stops!
  8. JP.

    JP. Screwfix Select

    240v Pump = Motor = DP switched to isolate surely? (reg somewhere for this)..or am I wrong?..Is the pump in fact 240v? as a matter of interest.
  9. wklivesvtime

    wklivesvtime New Member

    change the pump to a different load and see if it stops, if it does you got the culprit
  10. wklivesvtime

    wklivesvtime New Member

    good point jp, had not even picked up that one yet. It should have dp isolation somewhare along the line :)
  11. Hombrey

    Hombrey New Member

    thats what i thought JP, do you think that single pole switching of the pump would cause RCD to trip? Pump is 240V
  12. JP.

    JP. Screwfix Select

    thats what i thought JP, do you think that single
    pole switching of the pump would cause RCD to trip?
    Pump is 240V

    I cannot answer that Hombrey with conviction as have never come across that particular situation..however thinking about it would think not..unless there is some degree of neutral to earth degradation..that is just guessing though.
  13. wklivesvtime

    wklivesvtime New Member

    the sp switch should not cause a leak should it?
  14. wklivesvtime

    wklivesvtime New Member

    Swap the load man, i bet it is the prob!
  15. Hombrey

    Hombrey New Member

    not a leak, but somehow cause an imbalance because neutral is still connected and the pump wont stop immediately when switched off, it will come to a stop. I was thinking that perhaps the motor coil maybe causing some sort of imbalance through RCD as neutral is slill connected and phase is isolated. But probably just reading to much into it and the pump is just shagged, although it is quite new
  16. Hombrey

    Hombrey New Member

    I dont want to tell them their pump is shagged, replace it, and still have the same problem
  17. wklivesvtime

    wklivesvtime New Member

    swap it with another motor you have in the shed, or put a dp in line and switch it with that and see if it trips
  18. Hombrey

    Hombrey New Member

    I tried turning it on and off just by inserting and removing the plug, it didnt trip then, but it didnt trip every time i switched off at socket switch, its a bit random, just wondered if anybody had any similar experiences to back up my thoughts
  19. wklivesvtime

    wklivesvtime New Member

    its the pump mate i bet ya! Change it and let us know. If it wasnt ******** your way out of it :)
  20. JP.

    JP. Screwfix Select

    On a second perusal of the problem..maybe the motor cap is causing the trip with ref to SP switching..DP must be used before anyhting else as this at any level is what the regs state and could solve problem if cap is in fact fitted on motor..only a thought.

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