inexpensive long-term stay in Sonora?

Salt in the water. I should have thought of that! Most people don't realize that pure water is in insulator, not a conductor. It's the impurities in the water that conducts the electricity. Of course in Saudi we were pumping a slow trickle of seawater onto the grounding location.

"Turtle-Toad wrote:

I'm very aware of the NEC's requirements for ground rods; the value is 25 ohms or less for a single rod or multiples of rods. As you bond additional rods together you are creating parallel circuits and OHMS Law for resistances in parallel apply. And the 25 ohms is still the goal (and I might add that the just released 2014 version didn’t change any of this). If you can’t meet the resistance requirement, you either change locations or go back to the drawing board. In Saudi we used to either drive them in the water or dump water on the rod site.I've also used the water trick in Mexico...."


I use a 30" long piece of steel "varilla" rebar. Pound it into the ground, mix up a bucket with 3 gallons of water and a handful of salt. Can't do this around plants but the salt stays there. I tested this by direct short circuiting 60 amperes of 127vac through a six gauge wire, which of course blew the breaker. This was done in SAND, the worst possible media to establish earth ground. I use a cheap hose clamp to bond the wire to the rebar then gob a bunch of grease onto the clamp area. Me? Oh Hell No. My body is going to be the last thing on the face of this freakin' earth to "complete the circuit".

Almot wrote:

TravelingRae wrote:
I was at a Walmart recently where a guy was checking out the panels in the automotive department. The biggest capacity one was something like 20A.

You probably meant 20W. 20A is a lot of solar.

OTH, to live generator-free on 70 AH a day, even in Mexico, you need roughly 20A system, i.e. 300W - 350W. Rain in winter in Mex is unlikely, though cloudy days are, and the battery bank should be around 300 AH.

AM solar is an expensive store, though they have some unique items.

We had a great experience at AM Solar. It is expensive but I think top notch. We wrote all about it on these blog posts at our site:

http://www.walkaboutwithwheels.blogspot.com/2012/10/waiting-area-at-am-solar.html

http://www.walkaboutwithwheels.blogspot.com/2012/10/tuesday-at-am-solar.html

http://www.walkaboutwithwheels.blogspot.com/2012/10/wednesday-at-am-solar.html

http://www.walkaboutwithwheels.blogspot.com/2012/10/wednesday-at-am-solar.html

http://www.walkaboutwithwheels.blogspot.com/2012/10/our-first-full-day-using-solar-power.html

http://www.walkaboutwithwheels.blogspot.com/2012/10/am-solar-enters-customer-service-hall.html

http://www.walkaboutwithwheels.blogspot.com/2012/10/a-quick-summary-of-our-solar-system.html

We will be lifelong customers............

I think she means 6 amps of 12volts.

Moisheh

Turtle-Toad wrote:
I'm very aware of the NEC's requirements for ground rods; the value is 25 ohms or less for a single rod or multiples of rods. As you bond additional rods together you are creating parallel circuits and OHMS Law for resistances in parallel apply. And the 25 ohms is still the goal (and I might add that the just released 2014 version didn’t change any of this). If you can’t meet the resistance requirement, you either change locations or go back to the drawing board. In Saudi we used to either drive them in the water or dump water on the rod site.I've also used the water trick in Mexico....

The power company required no higher than 10 ohms. Switchyards even lower, the FAA required no higher than 100 ohms. With retesting done annually.
If NEC requires 25 ohms with multiple rods that's news to me, But I retired in 2006.

A couple years ago our local inspector just required two rods at least 8 feet apart did not care about any stinking values.
Is that really a ground? Depends on fault current.

I'm very aware of the NEC's requirements for ground rods; the value is 25 ohms or less for a single rod or multiples of rods. As you bond additional rods together you are creating parallel circuits and OHMS Law for resistances in parallel apply. And the 25 ohms is still the goal (and I might add that the just released 2014 version didn’t change any of this). If you can’t meet the resistance requirement, you either change locations or go back to the drawing board. In Saudi we used to either drive them in the water or dump water on the rod site.I've also used the water trick in Mexico, but in both places when you are adding water, you have to check your readings frequently.

I just didn't think we needed to get that deep into it. I also didn’t go into how you determine the size (diameter) requirements of the rod.

I've had to create ground planes in the middle of the Saudi desert about once a month when we were moving the Saudi's high speed coastal patrol boat squadron from place to place so I’m very familiar with driving multiple rods (and pulling them back up). You may have tested the ground rod connections but I have not only designed, but supervised the installation of whole electrical and communications systems, including the ground plane.

I agree that proper grounding and bonding is critical to ensure electrical safety.

I wasn’t aware of the Soares book. Thanks, I’ll have to check it out and maybe add it to my library.

Please reread the NEC they give a value for a ground rod. If that value is not met they require a second rod.
They error in that they do not require a value after you have installed the second rod.

Having tested ground rods to meet power company and FAA requirements. That require a value regardless of how many rods are needed. Let me just say all ground rods are not equal.

My Camper and I have survived two trips into Mexico.

(The common bonding of all metal surfaces is the key to safe electrical operation.)

I understand this book has a good history of electrical grounding.

OK, #1; As I mentioned in my post. In Mexico there is no built-in Ground Plane. There is no Ground bus in their distribution boxes. So to connect a ground to the source you would have to run all the way back to the power plant.

#2 According to the NEC (National Electrical Code) You should connect all your grounds to the main distribution panel via the installed ground bus's in each distribution panel. In turn, this panel is connected to an 8' copper grounding rod near or below your meter. There is NO ground coming in from the utility pole! The distribution panel is considered the source. On the utility pole that has the final step-down transformer on it there is a wire from the ground of the transformer down the pole to another ground stake! So, not only is the ground stake a good way to ground your it's the required method. The code also says that the only connection from the ground plane and earth shall be at the source. The reason for this is to limit circulating currents. There also is a connection between neutral and ground scattered throughout the electrical grid. The location of these are very strictly controlled by NEC and don't have much bearing on this discussion.

#3 Planes and cars have on-board generators or alternators which are grounded to the frame. All the DC electrical equipment is grounded to the frame. Of course the negative of the battery is also connected to the frame. There is NO ground wire running back to the source. Boats are a little different; they are sitting on the greatest ground plane in the world! Water! The ground wires from everything connect to a ground plane plate that is in the bilge. It, in turn is connected to a metal through-hull fitting or pipe. The shore power cable should have a 'ground isolator' between the ground wire from the pier and the ground plate. There are a multitude of reasons for this which we don't need to go into for this discussion. They also have the negative of their batteries connected to this plate but that also has no bearing on our discussion.

As to the radio equipment, antennas that are mounted on a non-conductive surface uses what is called a 'NGP (no-gound-plane) antenna' It's basically an antenna that also has a ground connection. Fiberglass cars, boats, and RV's use them. I've got 3 of them on my RV.

Turtle-Toad wrote:

pianotuna wrote:
Hi Turtle-Toad,

3 feet? I'd not trust that to be a good ground. 8 or 10 feet would be better.

Turtle-Toad wrote:


Also, I always have a 3' copper ground stake and jumper cables with me to ground my coach.

Hope this helps

Yeah, I know what the code is, but have you ever driven one of those monsters? Now imagine pulling it out! Since I'm only going to be there for a few nights, I settle for a 3' one and drive it into the mud under the water spigot or dump a couple of pails of water where I'm going to put it. It worked in Saudi when I was setting up mobile patrol boat stations and it works in Mexico, just keep the ground moist.

For safe operation electrical faults should trip a breaker or blow a fuse.
Ask yourself can this ground handle the 20 or so amps needed to trip a breaker?
Proper ground and neutral wiring to the electrical source will make you safer than any ground rod.

Remember fiberglass boats, airplanes and vehicles on rubber tires with no connection to a separate ground rod can still have safe electrical systems.
The common bonding of all metal surfaces is the key to safe electrical operation.
Of course radio transmitters require ground planes of some sort.

Stayed at Dome Rock, Quartzsite, AZ, one year for a few days. A big rig came in parked near and in front of us, and we had a most aggravating next few hours. His portable generator, placed outside near the back of his rig was set to auto start. Stop and go, endlessly it seemed. I think he left the next day so we didn't move away.