Are smaller homes better for the environment? How big is yours?

All my grounds on our gensets, buildings and PV assys are ground wires that lead directly into the lake, into deep water. I've never known if it is the best system, but it is better than trying to drill into the Canadian shield!

T

 

Oh god, that is an *incredibly* dangerous situation you have created!. Fresh water bodies, in comparison to salt water, are a very poor conductor of electricity. It also violates all modern code

I searched around a bit and came across this from one of our electrical periodicals:

The Case of the Hot Marina

The following is a CSA article on grounding pool fixtures, but it does state that fresh water - or "soft" lake water - can have a resistance of 300 ohms per cm, while sea water is usually 22 ohms.

July-August 2001: Ask CSA—Shock Hazard Test Probe for Submersible Luminaires for Use in a Pool

What that means is that if a person is swimming in a fresh water lake, they will usually appear to be a much better ground than the water itself. In the ocean that does not apply

In some cases, due to the resistance of the soft water, a lightning strike on the lake can actually travel UP the ground wire, into your summer home, and destroy the equipment.

I used to have a cabin, neighbor had a pretty bad lightning strike before I bought the place in the mid 90's. Like everybody else on the lake, we used submersible pumps to draw water.

A lightning strike on the lake travelled up the submersible pump, into his house, and back out to the transformer nearby. The pump, pump control box, and wiring was totally cooked. Fridge, stove, tv, etc were also cooked. Ontario Hydro had to replace the transformer

The previous owner of my cabin also had pretty bad electrical damage. I often wondered why the breaker box and pump control looked brand new. And I often wondered why a hard-wired surge protector was at the pump control box

I realize you have very limited options. The best possible ground would be to drill 12-20 ft into the Canadian Shield, as it has high mineral content. I realize that is not a practical option

Just keep in mind that you probably have no ground to speak of, and that a lightning strike on the lake could very easily backfeed into your summer home

 

Jayman,

I have no technical reason that I can argue your point. I think that the idea of lightning energizing the ground wire back to the system is an interesting one, and certainly one that I hadn't considered. It has been my understanding that the lightning dissipates it's energy quite quickly in the water.

On the land, I have seen, (and had) strikes that follow roots along the ground until they find a buried wire with a path to "ground"

I am a member of a Solar forum and we have had many threads on this subject. The consensus from the members (most of whom are way smarter than I!) seem to agree that the water ground is a pretty good alternative.

I would like to hear any other thoughts you (or anyone else) has on the subject so I can mull it over and share with my other cohorts.

Icarus

 

Jayman,

Reading your links about the Marina and the pool safety is interesting, but it doesn't really relate to our situation. We have no electrification of any facilities near the water, (docks, swimming floats, etc) so there is no chance that we could energize anything that way. My theory is that any stray ground fault current dissipates so rapidly in the lake that it cannot create a shock hazzard.

As for the pool link, clearly pools create a unique set of grounding hazzards, especially once you add lighting and sound systems to pools. Once again however, they don't really relate.

I would appreciate any further opinions

Tony

 

Re: When Buildings Talk, People Listen

Cool, based on your reply and Jayman's (no VOIP), I'm moving the router and modem to the PS and telling the wife to hit the power switch after shutdown. Should save some money and the environment a little (if she remembers). I can move the scanner there too but the cat won't be happy. He likes his personal heater. He's pretty old and somewhat arthritic, maybe we should let him keep his heat.

 

I put all that stuff (TV, Satellite reciever, modem, router, anything I can on timers on power strips. The modem and router come on in the morning and off at midnight, the TV stuff comes on at 6 pm and off at midnight. By setting them to come on a few minutes early gives them time to boot and it is seamless. Each of those items burn ~10 watts at idle. Multiply that by 6 items and you have the same wattage as we burn with cfls at night. It's a no brainer.

Icarus

 

Tony

A fresh water or "soft" water lake has very high electrical resistance, at least 300 ohms/cm. By contrast, oceans usually have resistance under 30 ohms/cm, Great Salt Lake lower yet

Due to the electrical conductivity of ocean water, sail vessels and other vessels can actually use the water as a ground point. But they have the opposite problem too, galvanic corrosion can occur due to how easily current flow is

At a salt water marina, one can be in the water and usually nothing will happen if a ground fault occurs on shore power. Although I don't recommend swimming during a lightning storm, one is also somewhat safe

A fresh water lake is a very dangerous place to be on during a lightning storm. A lightning strike on fresh water can travel a long distance, some folks have reported lightning striking a fresh water body and following horizontally until hitting shore

On fresh water, a lightning strike does NOT quickly dissapate its energy

I do know I had a bit of a surprise when I had to change the pump pressure switch. Had the breaker off, was unhooking the wires when I had a bit of a tingle. I thought it was the capacitor in the pump control box, so I pulled it out. Still a slight tingle

The submersible pump had its own ground wire. So I hooked up my dmm and was surprised to have a reading of 48 vac. It was a bright sunny summer day. The hardwire surge protector would not have done anything about that.

Again, given your location and options, there is little you can do. For tower structures on bare rock, it was fairly common practise to just run 8 ga ground wires 50-100 ft off each leg of the tower to form radials for grounding strikes.

Now, they hire a well driller to diamond drill a "well" about 50 ft, put in a copper ground rod, and backfill with an approved carbon product. I have some clients who had to do a series of deep wells 200 ft to achieve proper grounding and lightning protection

I'm just surprised this solar group would recommend "grounding" into a fresh water lake. IMHO that is a disaster/tragedy waiting to happen. If you don't believe me, try to call an Ontario Hydro electrical inspector. They used to have a toll free number, I called them once they had an office in Kenora. Probably one near where you are too.

On grounding, I would recommend looking around for soil. Unless the entire lot is solid ground, there must be soil or swamp somewhere. Another option that only applies during construction is to take advantage of a Ufer Ground

Not trying to scare you, just passing along work and practical experience

jay

 

Jay,

Don't get me wrong, I'm not discounting your advice, in fact I am thankful for it. I have reposted my question on my other site and I will hopefully get some sort of answer. (These guys are mostly EE's, and I trust them as well)

So if I am hearing your correctly, the water isn't "ground". That is the current in the lightning has to disperse through the water to "ground".

In my situation, there is little if any dirt. There is a thin layer of forest duff, and sometimes a bit of clay. In a very few spots I can find sands, gavel and clay enough to dig an outhouse pit. (The island is only 2 acres) Now that I think of it, perhaps I could send a ground wire into the outhouse. That might be a surprise during a thunder storm!

Icarus

 

I'll be the first to admit the NEC is remarkably convoluted, and one can "read" a lot into what is or isn't there. That said, I know around here it is strictly illegal to "ground" a system to a fresh water body

Correct for fresh water bodies. A salt water body is a fairly good ground

Again, given your situation, any solution will be problematic. To even drill for a ground rod, use the backfill, etc, would probably cost $6,500 and up. Not feasible in your situation

I'm going to bounce this problem off one of our grid engineers. Will get back to you on his answer

Would probably be a good ides to PM this from now on. We're probably confusing the OP