Pump keeps tripping

[Steevo]

I've got an underground tank taking surface water off the year, which has a submersible pump in it to pump it away. Whenever we have heavy rain spells, the trip switch on the circuit to the pump (and two other pumps) keeps tripping out. The pump fuse is fine.

I reset the trip today having found it had tripped out recently and the tank was overflowing with a big puddle around it. Came back 30mins later to check as the puddle hadn't dropped very far and found the trip had tripped again.

Anybody able to suggest what might be causing this?

 

[David.]

Sounds like a low level leakage of current somewhere on the pump or it's cabling. Maybe the rotary seal inside the pump housing that keeps motor section dry is getting past it's best, maybe the windings are breaking down and constant running when flooding occurs is the final straw that trips the overload.

 

[Steevo]

Thanks. The pump itself and 13A waterproof plug wiring is fairly new....Machine Mart version from about 3 years ago. Previous pump did 15yrs or so before corroding fully. But the rest of the armoured cable, trip, all other switchgear etc is likely 20years old now.

Pretty sure the previous pump did exactly the same. Or should I say the system did the same before I swapped the pump. I can't be 100% sure it's this pump that's tripping it....but it's the tank that gets the bulk of the water, and it always floods when it trips, whereas the others don't so shows they get much less usage.

 

[TheTallGuy]

Is it an RCD or a MCB that is tripping?

 

[Turra farmer]

Thanks. The pump itself and 13A waterproof plug wiring is fairly new....Machine Mart version from about 3 years ago. Previous pump did 15yrs or so before corroding fully. But the rest of the armoured cable, trip, all other switchgear etc is likely 20years old now.

Pretty sure the previous pump did exactly the same. Or should I say the system did the same before I swapped the pump. I can't be 100% sure it's this pump that's tripping it....but it's the tank that gets the bulk of the water, and it always floods when it trips, whereas the others don't so shows they get much less usage.

I've had same with submersible pumps , work fine on an old fashioned fused but with rcd would trip

 

[upnortheast]

Earth leakage not unusual wih submersible pumps. Sparky generally says beginning of the end for them

 

[Turra farmer]

Earth leakage not unusual wih submersible pumps. Sparky generally says beginning of the end for them

Ye , cheap enough to throw away

 

[Steevo]

Is it an RCD or a MCB that is tripping?

Just checked. It’s an RCD.

Good job I did check too as it’s tripped again.

 

[Timbo]

Have sparkie IR the pump , cabling and RCD. No point messing about wasting time.

 

[Steevo]

Have sparkie IR the pump , cabling and RCD. No point messing about wasting time.

IR?

 

[Pheasant Surprise]

aka megger test or insulation resistance (IR) test which check whether there is excessive current getting to ground (or neutral) via poor quality insulation in the switchgear, wiring or motor coils.

 

[Water Wheel]

fairly new....Machine Mart version from about 3 years ago..

3 years is all we ever get out of basic Machine Mart stuff, if it's working every day.

 

[Exfarmer]

I think you are lucky to get this with an MM machine.
I would get a DAB

 

[Steevo]

I think you are lucky to get this with an MM machine.
I would get a DAB

Thanks. Sounds like the pump may well need replacing then. I shall look into DAB.

 

[upnortheast]

Got good service & advice when buying a new submersible pump from this company
https://www.pump.co.uk/

 

[Steevo]

I think you are lucky to get this with an MM machine.
I would get a DAB

I think this is the current pump: https://www.machinemart.co.uk/p/051011260/

DAB don't do a pump with a 2" outlet at this volume. The Nova 600 which is similar in terms of output is only 1.25" and I'm not sure I fancy the strength of adapting that to a 2" with the potential leverage.

 

[Steevo]

Circuit seems to be tripping even more now since posting this.

Couldn't find a suitable DAB, so have ordered a JS pump as suggested by the local pump suppliers. Grundfos and Flygt worth considering too.

Will see how it performs.....

 

[Steevo]

Fitted the JS pump today. I have to admit it makes the Machine Mart pump look like a toy if you stood them side by side. Rather large weight difference too.

When I pulled the old pump out of the tank, there was a lot of mud/silt around the inlet strainer which must have been slowing the pump down which can't have been helping either. Surprising given the pump is suspended a good 3' from the base of the tanks - shows how much silt is held in suspension.

 

[milkloss]

That rcd doesn’t look too fresh, how old is it? Probably the pump but rcd’s can get moody.

 

[Steevo]

Still having trouble with this even after changing the pump. Whenever we get heavy rain like this it trips out.

Given it's 63A rated, I can't think it can be an overload (13A pump fuse would surely blow first if this were the case?).

Weak RCD?

RCD must be 25 years old I would guess.