The code says MINIMUM of 8ft in contact with soil. MAXIMUM earth ground impedance of 5 Ohm. So you need to keep driving in rods (or use an alternate grounding system) until you are below 5 Ohm - hence your multiple rods.
Alternatively, if you can prove that a single ground rod has less than 25 ohms to earth, then a single rod suffices.
If I have time later, I’ll try to look up the actual reference, but I remember reading and thinking “that makes no engineering sense!” so it stuck in my head.
Its actually IEEE and NFPA that recommend a maximum of 5 Ohms for the grounding system.
NEC state less than 5 Ohms for sensitive equipment, 25 Ohms otherwise. (NEC 250.56) - but as you mentioned, the measurement is only taken from first rod and a second can be inserted without testing (so it could be over 25 Ohms still, but based on the code it doesnt even matter....)
As an aside, its 200 Ohm in the UK (but it HAS to be measured - cant just blindly drive 2 electrodes and call it a day).
There are a few other (safer) ways that might interest HN readers, so sharing this video: https://www.youtube.com/watch?v=Yg6G5VUSsWA
I love electricians (and electrical engineers).
I did the calculations. One rod would have done it. Two if you wanted redundancy. The plan checker wanted four. Want to know why? He wanted one next to each post. As simple as that.
They want $1000 for a permit which would increase my payback time by at least 3 years.
I closely follow the relevant codes that improve my children's safety, but about half of the codes in my county are more about bureaucracy then safety.
Not saying safety isn't important. Quite to the contrary. However, there's safety and then there's making life impossible with things that don't really add to or enhance safety.
I am not exactly following code, as my earth comprises a 5 meter RSJ left over from construction buried 30cm down under a dirt road - we have very little soil over bedrock, but the soil is full of iron. It’s only half buried but I’m at 2.2 Ohm, so it should do the job - have soldered a nice fat cable to it to be my common ground.
That one change was the tip of a very large iceberg. They easily added somewhere in the order of $50K+ to the total cost of the system. I could have installed triple the power generation capacity for that money.
BTW, I did the bulk of the work on this installation myself (with the help of my kids here and there). No general contractor involved. Had there been a contractor on the job the cost would have been far greater.
Before someone jumps in and says "You probably screwed-up the design" (after all, this is HN). I designed the entire system, hired a civil engineering firm to review the design and calculations as well as provide stamped blueprints and calculations (you can't get a permit unless you have this).
I also consulted with the same plan checkers throughout the design process (before hiring the civil engineering firm) as well as with my suppliers and buddies who had built similar systems.
I only hired the civil engineering firm one the plan checkers told me verbally that all looked good and I should move forward, hire the engineering firm and submit the drawings and calculations for official approval and issuance of permit. I got verbal "All is good" from the structural, electrical, planing/zoning and fire plan checkers.
Three days after I submitted everything for approval the very same plan checker who told me all looked good rejected the very same plans he and I had discussed during weekly meetings for about two months. Things got surreal from there.
I spoke to multiple contractors from different trades during my many visits to the plan check office. I did not find one who did not have horror stories --multiple horror stories-- about dealing with these people.
Anyhow, it's a somewhat distant memory now.
> So, we did.
> They still made the project a nightmare to complete. They added a massive chunk to the overall cost and it took six months longer than it should have taken to complete it.
I read it that the excessive grounding requirements were just the beginning of a series of silly and expensive demands, which in aggregate made the project way more expensive.
It's that or it took six extra months to install four grounding rods.
Given some contractors I've dealt with --- I wouldn't be shocked. (or maybe I would be shocked, ... if they were allowed to do electrical work unsupervised. :) )
However, what I think he's saying is that despite blindly complying with this in hopes of a smooth project... the bureaucracy found other ways to make his project expensive, miserable, and slow anyways.
Hint: what the consumer can buy over the counter, and what gets used in a professional setting, are frequently two radically different things that may only be tangentially related.
There are other components used in contracting that have a bit more product segmentation, but the whole "frequently radically different things that may only be tangentially related" bit is wildly exaggerated. We use the appropriate components for the job, and often that means the same stuff you could buy at Home Depot. You're paying for that knowledge of what's appropriate/necessary and the labor to do the work, not for super-special premium contractor ground rods.
> They added a massive chunk to the overall cost
What? You couldn't afford four 19 dollar rods?
https://www.platt.com/platt-electric-supply/Ground-Rods-Copp...
Or four 36 dollar rods?
https://www.platt.com/platt-electric-supply/Ground-Rods-Copp...
PV array ground buses for something small scale will commonly be a single bare 6 gauge solid copper conductor bonded to the rods with 7 dollar hardware. Unless your setup is really huge, no more than 80 dollars of 6 gauge bare copper.
It's not like you need to buy a $800 thermite welding kit.
Why is this, and how do we get it fixed? Shouldn't this sort of burden be the same throughout the US?
Incidentally, this pattern is where a lot of conservative commentators are coming from when they say "liberalism is a disease". Non-liberals don't tend to exhibit this behavior - they move to an area, hunker down, shut up, and try to integrate.
I'm not sure what definition of “liberal” you are using, but there are so many obvious counterexamples that don't fit any of the plausoble ones that I can't see any way that that could be even a useful rule of thumb.
Missionaries tend not to be liberals, and indeed tend to be lionized by conservatives for doing exactly the opposite of “move to an area, hunker down, shut up, and try to integrate.” Conservatives don't object to liberals because liberals proselytize more than conservatives, they object to liberals because liberals disagree with conservatives.
Classical Liberalism if very, very far from what the Democratic party pushes these days. In fact, I would venture a guess that most thinking people are Classical Liberals. I make the distinction about "thinking" people not to be elitists at all, but rather because it is obvious that there are those who blindly follow and then there are those who choose to be more analytical and actually think rather than follow. Problems, as Einstein famously said, cannot be solved from the state of mind that created them in the first place.
This is where, I think, Classical Liberalism fits. I happen to think it is an ideology that would do the most good and deliver the greatest benefits across the board.
In case someone reading this isn't clear on the distinction, here's a good explanation:
Originally, the political Left was a name for classical liberalism based on where the liberals sat, as opposed to the conservative monarchists, in the French National Assembly. So if we’re fetishizing the original sense of terms, the distinction is nonsense.
Most of the political spectrum in the modern West (outside of the far right, which is classically conservative) is rooted in classical liberalism, which was nearly completely victorious over classical conservatism. They differ in whether they see the progress made by the 18th century liberals as the end goal or the starting point (“Left” evolved somewhat faster than “liberal” because that division became evident during the revolutionary period in France.)
> I make the distinction about "thinking" people not to be elitists at all
Yeah, you just think disagreeing with you ideologically can only be possible if people don't think.
> but rather because it is obvious that there are those who blindly follow and then there are those who choose to be more analytical and actually think rather than follow.
Sure, that much is true. The part that's less obvious is where you say most everyone that falls in the latter camp agrees with you ideologically while most everyone who disagrees with you is in the former camp.
This is an interesting comment. Or rather, thinking about how this could be --and, it is-- is what I think is interesting.
I've given this much thought because, as someone who tries hard to navigate an ideological center --borrowing what's good from each side and discarding the rest-- I have watched in horror as some of my friends and even a few family members have effectively become radicalized (the only word that fits) towards each of the ideological extremes.
My conclusion, or rather one of them, is that there must be a genetic element at play. Nobody is born with these ideologies. Just like nobody is born religious. And yet, over time, mental changes occur.
How can I explain my atheism and extreme skepticism? All I can grab for is that my brain is wired just different enough that it is able to go against the grain. Social pressures can be intense. I had absolutely no negative experiences with the church growing up. And yet, somewhere near adulthood I started to question it all and ultimately rejected it.
The same mechanism applies to political leanings. I've gone back and forth thinking that one school of thought was better than the other, only to realize +/- 25% from center is where the good stuff lies and the rest is just grotesquely wrong on both sides.
A long way to say that it is my theory that people who's brains are genetically wired in a certain way self-select towards the left or the right. This isn't an intellectual process at all. The failing being that very few of them ever take the time to, in fact, at some point, look at their positions through the lens of honest intellectual inquiry.
And so, the "Democrats" who leave CA and behave the same way they did in CA do so because, well, that's who they are. Just like "Republicans" are who they are. Genetically.
A lateral example could be had in Olympic class swimmers vs. wrestlers. Their body types are very different. Yet, swimming doesn't stretch someone out, make them taller and more slender any more than wrestling makes them short and muscular. The top achievers in both domains self-selected into those positions because that's the genetics they were handed. They build from there, but you can't take a short person and make turn them into world competitive swimmers unless they were also born with super-human endurance and power delivery capacity...their hull speed will be lower than that of a longer person.
The other interesting data point is found in the Hispanic population in the US. Quite a few of them got here by escaping from regimes that are not that different from the ideology that has currently taken hold in the American Left. And yet, surprisingly, they are voting for and supporting the same kinds of people and policies they left behind. Once again, my thinking is that this is simply who they are genetically rather being "Democrats" or "Republicans". After all, they had no clue about either of these parties before they got here.
It's an interesting problem because this effect has destroyed nearly every single Latin American nation over the last, take a pick, one hundred years. The policies that have permeated places like CA and are being championed as saviors for our country are the very same kinds of policies and ideology that have laid waste to entire nations. This isn't a matter of opinion, it's a matter of Latin American history, something we don't teach here.
I have friends in Argentina --where elections are about to take place before the end of the month-- who are in absolute fear of the Leftists once again gaining power. And when I say "fear" I am not being dramatic. They actually fear they will lose everything they have worked so hard to achieve during the last several years. Venezuela's Maduro regime is sending activists into Argentina to cause mayhem and disruption. In fact, a good deal of Latin America is on fire right now with the political Left trying very hard to either take control or gain greater control. They are attacking journalists and, generally speaking, unraveling the very fabric of civilized society. It's sad to watch this kind of thing form a distance. It's also sad to understand that if we, in the US, don't realize what these people are actually selling we stand a really good chance to end-up on a path that will forever transform this nation and not in a good way.
Anyhow, this stuff is really depressing to me. I can't see why people don't see what's going on. A lack of education in the actual history of other lands might be part of the culprit. I mean, how many Bernie and Warren supporters actually even know about The Gulag Archipelago, much less read any of it.
Not to get political on HN, but, well, California is now in the grips of a truly demented ideology. Due to having overwhelming majority everywhere, they can pretty much do as they wish. It's as close to a corrupt third world government as I hope we are ever going to get.
For example, our roads are in terrible shape. They have squandered or diverted funds that were specifically allocated to road maintenance. By that I mean: We voted to pass measures to collect additional taxes to fix the roads and they stole the money.
Another interesting one: They pushed and passed a law taxing any square foot of land that does not allow a drop of rain water to directly make contact with dirt. The tax is $0.025 per square foot. This means that your home, driveway, patio, patio cover, etc. are counted as part of this. Think of places like your local mall, Home Depot or strip malls, where 95% of the dirt is covered. This is huge.
I could go on. Like the high speed train to nowhere that we approved at a cost of $10 billion that is now near or past $100 billion. It goes nowhere, it isn't finished and nobody is gong to use it. And yet they don't stop. I would not be surprised if this becomes a half billion dollar project. The ROI on these things is so upside-down a fifth-grader could figure out it's a bad deal.
And, of course, there's this:
https://www.forbes.com/sites/davidblackmon/2019/10/10/califo...
And this:
https://www.forbes.com/sites/robertwood/2019/10/22/now-calif...
Covering the ground creates an externalised cost, basically someone else is being made to pay for the economic cost of that persons decision. Without a proper price signal externalised costs result in a net loss of wealth.
This is not a new thing. Laws dealing with the fact that rain water flows from property to property are in some of the oldest recorded regulations.
If the party in question poisons its brand to an extent that keeps them out of power for generations -- which is what they've already done in California and are busy trying to do everywhere else -- we will all end up worse off for it. The only thing worse than a two-party system is a de facto one-party system.
This is ridiculous beyond description and it is NOT in the N.E.C. at all.
The problem you run into with places like L.A. County is that incompetent plan checkers just want to play "cover my ass" and make up rules. There is no practical way to challenge them. They are the absolute authority (unless you have millions of dollars and YEARS to fight them).
I checked with contractors and the recommendation was "just do it and don't complain or they'll make your project a living nightmare".
So, we did.
They still made the project a nightmare to complete. They added a massive chunk to the overall cost and it took six months longer than it should have taken to complete it. Their interference made it such that this solar system will likely never recover the construction costs. Well, maybe in 30 years. It's a shame. Had I known the nightmare it is to deal with this bureaucracy I would have invested my money elsewhere.
California is sucking more and more with time. L.A. County is even worse.