[Question] submersible water pump

[Hotspot]

Good day all.

im currently doing a CoC on a small holding and just want yo know , does a submersible water pump (bore hole) need earth leakage protection? the earthing of the pump complies and all the protection in the control bored is fine but i want to know does the circuit need to be fed from a E/L?

Regards

[Sparks]

Unless you want it to pump electrified water, I would suggest, yes.

[AndyD]

It may be absolutely necessary but it may also only be recommended by the regs that a borehole pump is supplied via an RCD. Depends on the purpose of the pump (is its application critical?) and depends on the circuit supplying it i.e. is it on a plug and socket and did it comply at the time of installation and also has the circuit been altered or extended since etc. Without a lot more info I couldn't give you a definitive answer.

[Hotspot]

Thanx for the input guys appreciate it.
Well this is critical application,its the only water supply they have.
Do all motors need E/L protection for example 3phase/single phase motors in factories and so forth cause again the regs don't state it or maybe i am looking at my eyelids.
Regards

[AndyD]

No, motors as such don't specifically require earth leakage protection, it's the design of the circuit supplying them that may require that earth leakage protection is added.

[Sparks]

7.2.4.4.2 Submersible pumps
7.2.4.4.2.1 Unless otherwise authorized, a submersible pump shall be fed
from
a) a circuit protected by an earth leakage protection device with a rated
earth leakage tripping current (rated residual current) IΔn not exceeding
30 mA, or Amdt 3

[ACEsterhuizen]

7.2.4.4.2 Submersible pumps
7.2.4.4.2.1 Unless otherwise authorized, a submersible pump shall be fed
from
a) a circuit protected by an earth leakage protection device with a rated
earth leakage tripping current (rated residual current) IΔn not exceeding
30 mA, or Amdt 3

Could Regulation 7.2.2.4 as quoted above only refer to: (Circuits for Pools, Spas and Fountains)?

If we go back to reg 6.16.5.2:

6.16.5.2 Submersible motors and motors liable to flooding
NOTE See 7.2.4.4 for pump motors used in pools, spas and fountains.

Reg 6.16.5.2 deals exclusively with "Submersible Borehole Motor": (and makes no reference for Earth Leakage Protection)

6.16.5.2.2 Conductive parts associated with a water pump (such as the
suction pipe, the delivery pipe and the pump casing) shall be bonded to the
earth continuity conductor. In the case of a submersible borehole motor, the
bonding to the delivery pipe shall be made above ground and within 300 mm
of the collar that supports the pipe.

Just another perspective from my understanding, and of course i could be wrong.

[Sparks]

As you say, you may be wrong, but then again I may be wrong.
I understand 6.16.5 to be adressing motors and 7.2.4.4 to be adressing specifically waterpumps.
Pesonally I would rather err on the safer side.
In all the years, the regs have never been "cut and dry".

[REAList]

So what do you do with a Franklin pump that has two live wires - one for starting up and one for running.
I run mine with their smart control box with no earth going down to it.
You need a special 4 core borehole cable for the earth as well but mine is the 3 core.
This installation was done by a town electrician.


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[Justloadit]

You need to replace the drop cable.
It is imperative that the motor is earthed to the electrical system.
There are 2 reasons for this, one is that it protects the motor in the case of surges and lightning strikes. Because of the limited space in the motor, the enameling on the motor wire is reduced to get the correct number of turns for proper operation. This reduces the break down voltage to just over 1000V.

The second reason for the earthing, is for a user operational safety, in the case that there is any breakdown in drop cable or internal wire connections, joints etc.

Another reason, is if there is any failure to your system, the warranty will be void from the manufacturer.

[Sparks]

Usually a seperate earth wire is run down to the pump as the power cable has a watertight plug which does not accommodate earthing. The earth wire gets fixed to one of the bolts securing the pump to the motor by means of a lug.

[Justloadit]

Usually a seperate earth wire is run down to the pump as the power cable has a watertight plug which does not accommodate earthing. The earth wire gets fixed to one of the bolts securing the pump to the motor by means of a lug.

This may be an easier solution, but there is an earth wire in the lead out cable to the motor, which is for the earthing process. If this wire has bee left open in the well, this wwill create another situation, in which the water pressure will force itself down the copper wire (just like water down a straw) and finally land up in the motor socket, and in some cases, cause a connection between the prongs of the motor socket, blowing out the motor connection.

This is the reason that a proper junction is critical when joining the motor lead out cable which is approximately 1.5m long and the borehole cable. One tell tale sign of a good quality junction kit is to look at the ferrils supplied. The good quality ones, are not tubes to crimp the wires, but are drilled from either side, allowing an isolation wall between the 2 sides. So if the bore hole cable is nicked to the copper during installation, then water will not run down the cable via the tube which is caused by the copper wire and landing up in the motor socket.

[Sparks]

The Franklin submersibles which I installed never had earth wires in their lead out cables. Thus the reason for my external cable. My earth lug, the motor casing and the end of my earth wire were all sprayed with nickel spray which prevents corrosion. My joints to the well cables were all done with scotch kits.

[Justloadit]

The Franklin submersibles which I installed never had earth wires in their lead out cables. Thus the reason for my external cable. My earth lug, the motor casing and the end of my earth wire were all sprayed with nickel spray which prevents corrosion. My joints to the well cables were all done with scotch kits.

Not sure what motor size you would be referring too, but my experience on Franklin Electric motors up to at least 7.5kW, I have seen both the European and American based lead out cables (difference is the colour of the wires), and they all come with the earth cable, and the actual motor plug and socket has 4 pins. And knowing the company, there is no way that management would even consider to supply the lead out cables with out the earth cable, as this would violate their internal specifications, and to make a physical change like this would cost them millions of dollars in resetting their tooling and automated production lines.