Water feature pump tripping ELCB

tommymcg;731877 Wrote:
Hi
I recently purchased a water feature from B&Q and when the
installation was complete it was noted that when the pump was switched
off it tripped the ELCB on the consumer unit
I understand that the amount of inductance generated by the motor
causes a spike when the unit is switched off and this is the cause of
the ELCB tripping. Further research has revealed that a suppression or
"Snubber" circuit which is comprised of a resistor and capacitor in
series will eliminate this type of problem.
Has anyone else experienced this type of problem and are these type of
"Snubber" circuits available for purchase?

Regarding your elcb tripping the good news is it seems to be working
but as an electrician there is not always a straitforward answer to
seemingly simple "Quirks" of electricity Firstly if the switch you are
using to switch it off should be a double pole switch once switched off
ther should be a permanant dissconection between the pump and the elcb
controling that circuit hence any assumed spike from the motor has no
where to go except to earth and since it should be double insulated as
a pond pump therefore my guess is that there is a fault with either the
switch arrangement or the pump insulation
Since b&q operate one of the best returns policies I know of I would
consult a friendly electrician who can meter the windings of the pump
and advise on any switching changes you may need...You don't say if you
have a Split load Consumer unit or not As far as the inductance is
concerned once dissconected since no current is flowing in the motor
there should be no inductance unless the motor has a permanant magnet.
don't faff about with snubbers and such as you would have to double
insulate them to make them safe Just change the motor at B&Q and If the
Replacement does the same Get your money back.




--
garden-helper