This article was posted 08/30/2006 and is most likely outdated.

Protecting Submergible Pump from Lightning
 

 
Topic - Lightning and Surge Protection
Subject - Protecting Submergible Pump from Lightning

August 31, 2006  

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Protecting Submergible Pump from Lightning

 

Question from newsletter member:

 

imageMike,

 

I have a 150’ ground water well with a steel encasement, the well has a submergible pump located at the bottom of the well with a ground wire going to the pump.

 

The steel pipe/encasement for the submergible pump is not grounded to the electrical system. The pump seems to burn out and trip the breaker for no apparent reason.

 

I am thinking of grounding the steel pipe/encasement to the submergible pump ground wire, due to lightning traveling down the ground wire 150’ to the pump housing. However, I am not sure if that will only make the problem worse, due to more surface contact with the earth. This site is located in the Florida Everglades with lots of lightning, any recommendations?

 

Chuck Maxfield

Apex Electric

 

Mike asked his friend John West with Power & Systems Innovations, Inc. to respond:

 

Most wells are installed without consideration of the impact the earthing effect of the casing and what can happen with nearby lightning events. The energy of lightning is not predictable, but most often it follows any and all paths that present a lower potential. Lightning traveling in the ground will see the well casing the same as lightning in the air would see a 150’ tower. It will couple with the casing and follow the conductors of the pump back to the “lower” potential. That most often will burn the pump out. There are two things you can do; bond the casing to the service ground and install a good performance TVSS (surge protector).

 

If I understand the installation (if I don’t please correct me) the well casing is not bonded or connected in any manner to your electrical service ground bond. There is no doubt the well casing is the best ground you have available. As you have stated it is probable the pump damage has resulted from lightning.

 

Part 1: I recommend you bond the well casing to your service entrance grounding. The distance between the well and your electrical service would determine the size of the conductor. Our firm uses 4/0 bare stranded conductor in most cases. In corrosive or salt soil areas we use tinned wire. The larger the size of the bonding conductor the better. The well casing may be “pickled” steel and if so you will need to use a bi-metal clamp to transition from the steel to copper. The key is surface area…. if necessary use some Penitrox, but make 100% sure you have a very solid connection as it can be under severe stress during a lightning event. Most of the energy during a lightning event will follow the “bond” you have created and not end up burning up your pump motor. I recommend you verify the service ground is 25 Ohms or less and the X/O bond is well made. The well casing will act as a shield (such as conduit can for the wire inside) and keep the energy away from the pump motor.

 

Part 2: Install a substantial (50-100kA per mode) TVSS at the well (my preference) or on the panel feeding the well. If the circuit is less than 40-amps (any single phase voltage) there are series installed TVSS rated at 72kA available.  You cannot have too much surge protection when lightning is involved. My own home has a well for irrigation I have a robust panel surge protector installed on the main panel and series connected on both my well and AC unit.

 

Our firm has worked with US Sugar, numerous growers and Bonita Springs Utilities to solve similar issues. If I can assist further please contact me.

 

One major grower we have worked with has over 200 wells. Most are three phase and over 100hp. Bonding the service entrance to the well casing along with surge protection stopped all but a very few of their pump motor damage issues.  US Sugar told me the combination all but stopped their damage and also significantly lowered their unexplained failures.

 

Nothing is “lightning proof” but I am sure you will see a significant lowering of the damage…….

 

John N. West, Sr.

Power & Systems Innovations, Inc.

P.O. Box 590223

Orlando, FL 32859-0223

Phone: (407) 380-9200

Fax: (407) 380-3911

 

 
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Comments

  • I have hooked up heavy industrial machinery using 4 wire aluminum SER cable and every installation had ABSOLUTELY NO PROBLEMS with the aluminum wire.

    The first machine was a 60 KW plastics machine for squishing the tops and bottoms of PVC cooling tower cells. When is production, this machine ran 100% duty on half of the heaters and 90% duty on the other half of the heaters. There was enough cycling during lunch and bathroom breaks to prove that the terminals will not loosen up. This machine ran 24/7 for 6 months except tor Thanksgiving, Christmas, and the 2 times that the COPPER wiring in this machine broke down during the first 2 months of this machine's life.

    Since Ilsco Deox passed the 3 year salt spray test on the starter motor on the car, I inherited a stack of #220 silicon carbide abrasive paper from grandfather, and I had read Dr. Jesse Aronstein's early work on aluminum wire, I figured that I could do this in aluminum. I used Dr. Aronstein's recommendation of using the silicon carbide paper, elbow grease, electrical grease method on all of the wire strands. There are other issues such as overstripping the insulation so that I could use a screwdriver to establish a strand bending area, cutting off the sharp tips of the strands before scrubbing them, recompressing with a hose clamp, and using a file to chamfer the outer wire strands so that they will go into the lug better. You also need plenty of paper towels and something to degrease your hands and tools.

    Some other issues was that this project took place right after the stock market crash and copper inflation in October of 1997 and I was bringing 200 amps 240 volts corner grounded off of a busway that was in an attic. To make things more fun I had to use a 75 KVA transformer to step up to 480 volts ungrounded and ran #2 aluminum SER cable from there to this machine.

    For more details go over to my website at home dot eathlink dot net slash tilde mc5w . Dr. Aronstein's website is www.inspect-ny.com . Dr. Aronstein has also scientifically proven that a wire brush is 100% INEFFECTIVE at removing aluminum oxide from aluminum wire.

    You can also get lalluminum alloy weldment ugs from Sefcor that you tungsten inert gas weld weld to aluminum wire. You can also get copper lugs from Burndy that you exothermically weld to copper wire. Both kind of lugs are not tin plated because welding heat would destroy the plating. After the lugs cool you will need to use silicon carbide paper, elbow gease, and electrical grease to establish a connection that is free of copper oxide or aluminum oxide.

    Also, copper wiring that is out of doors will oxidize just as fast aluminum thanks to catalytic converters from cars. Not as bad as the amounts of ammonia as the air in a foundry has but still enough to mess up the wiring.

    I have seen more in the way of copper wiring burn up than aluminum. As far as I am concerned, if the lugs are big enough to accept aluminum wire I can do the work better than the way that most people do copper.

    Mike Cole mc5w at earthlink dot net Tel: 216-524-2185

    Michael R. Cole
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