Electrical Submersible Pump Cables

Submersible pumps usually use butyl cable. It's more resilient to damage to the sheath.

The flet three core cable is the submersible cable.It is water proof.Water sealing is done using petroleum compound in pvc tube.

Some submersible pumps rely on the supply cable for venting the sealed electric switching/connection area to the atmosphere.

Please check if your pump is of that kind. If so, ensure that the cable chosen provides a porous core for internal air pressure venting to atmosphere.

Sub-pumps with an integrated bellows that permits detection of submersion level by casing flotation are the classic type needing a cable with porous core.

Mark Bingham
Relativity PL

Could you explain what you mean by

"Some submersible pumps rely on the supply cable for venting the sealed electric switching/connection area to the atmosphere."

and

"ensure that the cable chosen provides a porous core for internal air pressure venting to atmosphere."

In the submersible pumps I use, setting at depths of over 2000 meters, the last thing we want is the pressure inside the motor to be less than the outside well pressure, in fact we need it to be the same. The cable connections are constructed so there is a gas block preventing migration of any gas, air or otherwise in or out of the motor, therefore helping to maintain the motor internal balanced pressure. But this is for DEEP wells. If as I suspect, the OP is only looking/asking about cable for small pumps and with a minimal depth of submersion.. will the external pressure be that high?

The reason why the pumps I use must have the ability to equalise the internal pressure is as follows...

Think of the motor stator as a sealed tube that is being crushed from the outside because the inside of the tube is at 1 bar absolute and the outside is at 200bar (1 bar for every 10 meters).. the tube will be crushed, and in the case of the motor, the stator will collapse onto the rotor stalling the motor and tripping on overload or burning the motor.So it is vital to the operation that the internal motor pressure equals the external well fluid pressure

However, I'm not saying you are wrong... it just seems a strange thing to do!

Cable and gas.... the cable can never be 100% impervious to gas, and gas can migrate up the cable as a gas molecule is way smaller than a water molecule. So in the case of a gassy well, you want the Hydro-carbons to come to surface and not build up in the cable, if they do they will blow the cable outer sheath and you need to pull the whole completion. However where does the gas go? To surface, but NOT to the electrical switchboard.... Hydro-carbons & electric sparks equals BOOM!!

So yes, the cable must vent to atmosphere, ONLY to get rid of the highly volatile gaseous mix that has in the past blown switchboards to bits the second the motor contactor opens. Is that what you meant?

Thankz guys, a friend told me that PVC is not water proof material anyway, so we get a flex cable with TPE sheath, its data sheet shows it is submersible upto 500meter, I dont know about 500 meters, but it should be ok for 10 meter.

Thankz for all you reply,