600 yard to pump

Status
Not open for further replies.
mtnelect said:
"If I said well that’s my bad it’s on the local lake. My dad has water rights and we lost power. Diver found a Beaver attached to the line. Says there is miles of Unsed wires in the lake and splices all over. I will not let my kids swim there is a death trap".
Click to expand...
If they are unused, they are probably disconnected and not a hazard.
But in general it is not safe to be in water where there is electrical equipment in that same water. Nothing, other that a neutral isolator can make it safe from one of the most common issues, that being elevated Neutral to Earth Voltage. It is often very difficult to get the utility to install a neutral isolator
The only reason a code compliant pool is relatively safe is because the code required bonding raises the voltage of the water and everything that can be touched while in the water to the same voltage eliminating any potential differences. That is not something that can be accomplished on a lake or river.
 
Last edited:
winnie said:
No system can be perfect. As long as we have electricity near water there will be an electrocution risk.

The OP has a system to be repaired and a customer willing to invest the money to repair it.

What is the best practice to practically minimize the risk presented by the customers pump?

Installing wire with intact insulation and an EGC is code required and IMHO a great first step. Is that sufficient? Simply doing regular maintenance on systems is the most important safety measure.

Does wire type make a safety difference? I'd imagine (but have no real data) that something like SE cable, where the concentric neutral is used as EGC would be desirable.

Protecting that cable in conduit may not be required, but is probably a very good practice since the added costs get balanced by reduced maintenance costs. A conduit may even be cheaper for the customer long term.

Adding a GFCI might actually reduce safety, if nuisance tripping means the protection gets bypassed. Would it be better to install GFPE? What about placing the GFCI near the end of the run? Would fault monitoring (some sort of leakage current meter) make more sense than a leakage interrupter?

What about bonding? Code would require the EGC for this circuit to be bonded to the supply system ground and thereby to the mains neutral. We know that mains elevated neutral potential can cause shock hazard. Would breaking this normally required bond improve safety? How would you do this yet be code compliant?

Jon
Click to expand...
Breaking that bond eliminates the EGC being used for fault clearing. One method, that is sometimes used for dairy farms, is to get the utility to install a neutral isolator between the secondary of their transformer and the service equipment.
 
mtnelect said:
"If I said well that’s my bad it’s on the local lake. My dad has water rights and we lost power. Diver found a Beaver attached to the line. Says there is miles of Unsed wires in the lake and splices all over. I will not let my kids swim there is a death trap".

This is not just a conversation about "Code" anymore. This is a real-life safety issue. I just sent an Email to Mike Holt, explaining a life safety issue on his forum, and what support he will have to protect life and safety. Would you allow your family to go into this lake ?
Click to expand...
If you watch all of Mike's videos, you will see that he has said more that once, that you should never enter the water of a lake or river that has electrical equipment in the water anywhere near where you are at, as it is not possible to make it completely safe.
 
don_resqcapt19 said:
Breaking that bond eliminates the EGC being used for fault clearing. One method, that is sometimes used for dairy farms, is to get the utility to install a neutral isolator between the secondary of their transformer and the service equipment.
Click to expand...

Yes. I was wondering if there were a code compliant way to installing a customer owned isolation transformer, and isolate the secondary EGC from the primary EGC. I am aware of neutral isolators used on the utility side of things, but nothing on the NEC side of things.

-Jon
 
winnie said:
Yes. I was wondering if there were a code compliant way to installing a customer owned isolation transformer, and isolate the secondary EGC from the primary EGC. I am aware of neutral isolators used on the utility side of things, but nothing on the NEC side of things.

-Jon
Click to expand...
I don't think that they are compliant unless installed by the utility.

I think it would be possible to install an elevated isolation transformer and not have any connection to the primary neutral or primary EGC, but not all agree with me. This opinion is based on 250.110(1).
250.110
(1) Where within 2.5 m (8 ft) vertically or 1.5 m (5 ft) horizontally of ground or grounded metal objects and subject to contact by persons.
Click to expand...
That says to me if I can install the transformer on an elevated, non-conductive structure, I would not have to run the primary EGC to the transformer.
The secondary would be grounded to a grounding electrode in the area of the transformer. This would eliminate the issue of elevated neutral to earth voltage, but have doubts you would get the AHJ to agree.
 
winnie said:
Yes. I was wondering if there were a code compliant way to installing a customer owned isolation transformer, and isolate the secondary EGC from the primary EGC. I am aware of neutral isolators used on the utility side of things, but nothing on the NEC side of things.

-Jon
Click to expand...
They do for operating rooms, but that is a totally different animal and use.
 
I might be confused, but aren't neutral isolators generally used where there's a problematic voltage gradient caused by the primary (15,000 volt) distribution network? Isn't the question of the day how to install a safe & economical low-voltage (240 volt) branch circuit?

If electrical isolation can't provide a satisfactory, confidence-inspiring solution, maybe the answer is physical isolation.

Install the pump on dry land, put it on a Ufer pad, surround it with a local equipotential bonding network, provide an EGC (sized with consideration for voltage drop) back to the panel, and install a non-conductive suction pipe into the lake.
 
Food for thought:


(Note the part about the redundant ground wire and electrode, which IMHO reduces risk from a failure in the pump supply circuit, but might increase risk caused by utility failures...)

The new pump the OP's customer bought might even say explicitly that it isn't permitted in bodies of water where people swim.

I suggest that the OP look for a similar requirements document applicable to the installation location.
 
More: https://archive.independentmail.com...om-hartwell-lake-ep-413196808-349284631.html/

"I've got five different kinds here," Campbell said from her Georgia office near Hartwell Dam. "The packaging all says ?Danger. Risk of electric shock. Do not install in swim areas.'"


I knew about this use of well pumps in lakes, and just assumed that if installed properly it was safe enough. Now I think I've changed my stance. IMHO if the pump is explicitly designed and listed for such use I'd be okay with it, but it appears that standard practice is to install pumps intended for wells.

Also, as of a decade ago all (most) submersible pumps were explicitly prohibited from being used in swimming areas by manufacturer instructions.
 
drcampbell said:
I might be confused, but aren't neutral isolators generally used where there's a problematic voltage gradient caused by the primary (15,000 volt) distribution network? Isn't the question of the day how to install a safe & economical low-voltage (240 volt) branch circuit?

If electrical isolation can't provide a satisfactory, confidence-inspiring solution, maybe the answer is physical isolation.

Install the pump on dry land, put it on a Ufer pad, surround it with a local equipotential bonding network, provide an EGC (sized with consideration for voltage drop) back to the panel, and install a non-conductive suction pipe into the lake.
Click to expand...
Many of the issues associated with voltage and water come from elevated neutral to earth voltage as a result of the primary neutral being connected to the secondary neutral and the service grounding system.
 
Does the site actually have a neutral-earth voltage problem, or is that just speculation? Would it even matter if it did, this being a dedicated circuit for a hard-wired 240-volt pump?

Last I heard, we were talking about a beaver-damaged existing installation that quit working, which needs to be redone ecause it's somewhat the worse for wear.
 
This has been my premise all along.

I see no way to make installations reasonably safe in a body of water where we cannot energize everything like we do in a pool. At least not until the utilities are prohibited from using transformers that have the primary connected line to neutral.

don_resqcapt19​

 

Attachments

  • MultiGroundedNeutral #2 .pdf
    185 KB · Views: 16
Last edited:
mtnelect said:
This has been my premise all along.

I see no way to make installations reasonably safe in a body of water where we cannot energize everything like we do in a pool. At least not until the utilities are prohibited from using transformers that have the primary connected line to neutral.

don_resqcapt19​

Click to expand...
you have posted that document about 30 times...I have ZERO interest in reading anything written by that author.
 
Would it be possible to create a safe situation by installing a jet pump away from the pond, and using plastic pipe for the suction? I am not sure of the possible consequences.
 
Status
Not open for further replies.
Top