diy solar

diy solar

Need to ground off-grid system but NO soil for ground rod. What would you do?

smoothJoey said:
That fluff doesn't link to anything authoritative.
If fresh water isn't conductive, how does the current get from the boat to the person?
I'm sceptical.
Click to expand...

My theory is that we only hear of freshwater electrocution around here in a marina because there can be multiple current sources.

My experience is that an open extension cord was in the water for a few minutes and couldn't draw enough current between the hot and neutral to trip the inverter off.

I started a new thread here to discuss:

diysolarforum.com

Fresh Water Conductivity and GFCI

So here is my latest display of stupidity: Last Friday I was up on top of a boat lift inside a metal boathouse. I was running an angle grinder powered by my 48v LiFePO4 through a 3KW inverter. I know this starts out like a @ghostwriter66 oilfield idiot story and I guess it is! As I moved...
diysolarforum.com diysolarforum.com
 
My theory again, may not be based in fact.

However, couldn't a significant resistance be overcome by multiple voltage/current sources as opposed to a single point?

Kind of like shoving current/voltage through a few 4/0 cables could power something that a single 26g wire cannot.
 
JoeHam said:
My theory again, may not be based in fact.

However, couldn't a significant resistance be overcome by multiple voltage/current sources as opposed to a single point?

Kind of like shoving current/voltage through a few 4/0 cables could power something that a single 26g wire cannot.
Click to expand...

Code: 
boat_with_bad_ground_1<->|
boat_with_bad_ground_2<->|<->water<->human<->water<->ground_rod<->poco_transformer
boat_with_bad_ground_3<->|

Like this?
 
I have seen Fire look outs high a top of granite peaks with long grounding cables stretched out in 4 directions. I do not know how they work but perhaps you could research what they do.
Click to expand...

I have seen the same, believe the intent was path for lightning away from tower.


What is the reason to ground, so you can have working GFI's? I have seen lots of non grounded systems....
 
How bout this one?
Human is in the water and the neighbour boat with a proper ground connects to shore power lowering the impedance of the fault path.

boat_with_bad_ground<->water<->human<->water<->boat_with_good_ground<->neutral<->poco_transformer

P.S. I'm just a ton of fun at parties.
 
Yes joey that is a short summary. If you were interested you can find much information about this emergency and read many experts describing this major problem. You have permission to grab a beer and use Google. Would you explain why you call stories about dead victims "fluff".
 
Zil said:
Yes joey that is a short summary. If you were interested you can find much information about this emergency and read many experts describing this major problem. You have permission to grab a beer and use Google. Would you explain why you call stories about dead victims "fluff".
Click to expand...
Because there are no citations
Because its the Fluffington post
Because it includes this gem "Boats are typically leaking 6 amps or 6,000 milliamps which jolts us like an instant ventricular fibrillation when we are in the water."
 
DO NOT QUOTE ME .... but there are times that I cannot put a rod into the ground due literally granite hardness under me and not being able to use C4 anymore unsupervised ... In order to get a good earth ground we try to scrape as much dirt as we can to create a trench (sometimes its only an inch or two ) .. then we LAY the ground horizontal in the trench, and cover the rod with as much dirt as we can pack on top ...

from an electrical point of view it works for us ...

BUT PLEASE CHECK WITH YOUR LOCAL CODES AND ORDINANCES ... Here is SW Texas our Codes and Ordinances only has two things on it

1. Don't do anything that will damage any of this expensive equipment
2. IF you can, try not to kill anyone in the process.
 
Well the telecom company up this way has bonding straps for their outside plant that go down into the water. Their plant is designed to take power hits all the time.

I'm using a 1000W inverter at my panel and I'm planning on running a GFI on every branch circuit leaving the shed. The GFI's would be grounded to the line that goes back out into the water. Any stray current would trip the GFI first anyways right?

And as for lightning, no one swims in lightning up there anyways and if they do, they deserve the Darwin award.

Gonna go check out that forum.
 
smoothJoey said:
The potential is still 120 volts(assuming north america) no matter how many extension cords are in the water.
Click to expand...


It could be a total surface area thing with many cords but I surrender. No more theories today ?
 
Here's an interesting snippet from a mikeholt.com forum post.

Grounding & Bonding: The Big Picture Post

Grounding Vs. Bonding The Big Picture What is “grounding”? What is “bonding”? What’s the difference? Grounding and bonding is probably the most discussed issue here, aside from 210.52’s design requirements. The following is based on a solidly grounded conventional wiring system. For...
forums.mikeholt.com
Electricity does not seek the path of least resistance to the earth. It seeks all available paths back to its source, in proportion to their resistance. The reason that a person gets shocked when touching an ungrounded conductor and the earth is because the neutral of the system is repeatedly connected to earth in a grounded electrical system. The earth becomes part of a return path to the transformer – it’s part of one route back to the source; the earth is not the destination for the electricity.

Driving a ground rod to ‘ground’ any electrical equipment does not provide the low-resistance path required to trip breakers. Driving a ground rod, or using a Ufer, or a metal water pipe is not a substitute for an EGC. A ground rod with 25 ohms to earth will allow almost five amps to escape the system into the earth when directly energized from a 120V source. Five amps will never trip a 15A or 20A breaker, and in the meantime everything bonded to this ground rod will be energized to 120V.
Click to expand...
 
MorganCarey said:
Here's an interesting snippet from a mikeholt.com forum post.

Grounding & Bonding: The Big Picture Post

Grounding Vs. Bonding The Big Picture What is “grounding”? What is “bonding”? What’s the difference? Grounding and bonding is probably the most discussed issue here, aside from 210.52’s design requirements. The following is based on a solidly grounded conventional wiring system. For...
forums.mikeholt.com
Click to expand...
That is good information but incomplete without the full forum page post. As always the devil is in the details of the NEC as applied to your situation. I understand Code Compliance is not an issue but ultimately safety seems to be your motivation.

From that forum post -additional research would be required to establish what needs to be done for your install. Also remember that EGC is an alternate path of travel for stray energy outside normal circuit conductors/ground.

The following quote guides us to the relevant sections of NEC:
The terms are defined in Article 100 and 250.2 of the NEC. Section 250.4 provides the performance requirements of Article 250. Grounding is a connection to earth, and bonding is the connection of items to each other.
Click to expand...
 
An idea for the brain trust to cogitate on...

If you can't go under (really unfair to limit your c4 access), how about over?

That is scrape away to bedrock, then layout forms to pour concrete in as if you were doing an ufer ground (but above ground, not below), then haul in fill to bury the whole thing? Perhaps mix Sodium polyacrylate in with the fill to keep it moist? Or rather than fill, perhaps just dredge mud from the lake bottom?
 
You must log in or register to reply here.

Similar threads

D
Off-Grid System: Check my work
Replies
12
Views
863
eod1991
eod1991
J
From Harbor freight special 12 Volt Off Grid learning system, to new ground up build off grid solar build plan.
2
Replies
22
Views
1K
Doggydogworld
Doggydogworld
A
how to decide which breakers and cables/wires you need for off-grid system based on the components you have ?
Replies
1
Views
334
Abdurrahman
A
Back
Top