submersible water well surge protection
submersible water well surge protection
(OP)
We are having problems with submersible water well pumps (with motors) failing due to a surge. Our latest design is having surge protection at the service entrance and at the power cable junction box located at the top of the water well head. Both surge protection devices go to ground via a 20' copper ground rod...and these are bonded together via #4/0 bare copper wire. We still are having surges though. I have read that a ground rod does not provide good grounding for the surge protection at the well head...something about ground the aboveground surge components to the motor frame or to the well casing that goes below the well pumping level. Oh yeah, the submersible is approx. 700' below grade. Any ideas or suggestions on better implementation for this application?





RE: submersible water well surge protection
1. Most important is that the surge protection be as close to the equipment you are trying to protect as possible.
2. Grounding connections from the surge arrester to ground should be as short as possible with as few bends as possible with a large copper conductor.
3. Resistance to earth should be as low as possible.
Usually for a submersible, the best approach is a direct bonding from the surge arrester to the metal well casing. You could also add a buried ground ring with multiple ground rods around the wellhead.
RE: submersible water well surge protection
When you say "Usually, for a submersible..." What size (in HP) are you talking about? The submersibles that I am writing about are in the 100 HP to 350 HP range.
Thanks again.
RE: submersible water well surge protection
Keeping the ground connection short and straight is often overlooked, but it is very important in providing a low impedance path.
Some submersibles are fitted with built-in surge suppression - that is a good option when available.
Are these running constant speed or on VFDs?
RE: submersible water well surge protection
RE: submersible water well surge protection
Usually we connect the surge protection devices to ground rods via bare copper wire (#4/0), but after some reading I am considering tying all the rebar together within the concrete base and footings for the well head and bond that to the ground bar(s).
Any thoughts or concerns would be greatly appreciated.
RE: submersible water well surge protection
RE: submersible water well surge protection
RE: submersible water well surge protection
You might look at GE Tranquell Secondary Arresters.
You should put a heavy duty arrester at the service entrance and make sure you are protected between each phase to ground as well as neutral to ground. Then put another arrester at each wellhead.
RE: submersible water well surge protection
I would look at the cost/benefit of the protection.
Before you spend all the time and money on surge protect, I would spend some time reviewing your current motor protect. I frequently talk to customers that are upset taht their motor protect didn't prevent a failure. I then look over their motor protect and they have heaters.
RE: submersible water well surge protection
Are you worried about lightning? What exactly are these "surges"?
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: submersible water well surge protection
These "surges" come either from a lightning strike near the well or a power surge from the local utility. As of yet, we still have not been able to completely tell exactly from where one has come.
RE: submersible water well surge protection
Ok seriously, I am not familier GE Multilin so no comment about it. I'm a big fan of the Syc-com produce line.
If I understand your statement, the GE product is protecting the whole MCC, you need better protection at the starter.
One other thought, What is the class rating on the GE? Submersible motors are a different breed. All manufacturer's that I know of require class 10 overloads. This is something that regularly gets overlooked. ( I have asked this of many electricions and they look at me like I'm crazy) Submersible motors for warranty requirment are only allowed to run at +/- 10% for voltage and 5% for current imbalance.
Finally, is it a drain back system and if so does it have a back spin time (on delay) ?