Irreversible connections for ufer

[Jerramundi]

I have seen countless installations with one rod or no rods at all and they have been fine for 70 years.

With respect, I think you should be careful with this rhetoric. We don't design safety systems for those 70 years, we design them for that 1 millisecond when something does go wrong... and the worst of the worst DIY installs could be fine for 70 years, but it's that one millisecond that makes the difference between someone getting seriously hurt or walking away unscathed.

 

[infinity]

With respect, I think you should be careful with this rhetoric. We don't design safety systems for those 70 years, we design them for that 1 millisecond when something does go wrong... and the worst of the worst DIY installs could be fine for 70 years, but it's that one millisecond that makes the difference between someone getting seriously hurt or walking away unscathed.

Does the grounding electrode really provide much shock prevention? IMO the MBJ is more important than any electrode(s) in preventing someone from getting an electric shock.

 

[Jerramundi]

Does the grounding electrode really provide much shock prevention? IMO the MBJ is more important than any electrode(s) in preventing someone from getting an electric shock.

In a lightening strike event it most certainly does. And again, we design these systems specifically for that millisecond that something goes wrong. If we went by the logic that "it'll be fine for 100 years," more than half of the NEC would be null and void... and more than half of the DIY crap that we regularly mock, and mock for good reason, would be justifiable.

We used to have a system without grounding electrodes at my parents place. My father always tells this story of a lightening strike in which he could see the electricity bouncing around the basement because there was no electrode. Now, I should clarify that my father likes his stories, lol... but I kinda believe him, lol.

 

[roger]

Lightning may or may not be dispersed by a service GE, in reality bonding things back to the MGN is better protection.

This guy laughs at lightning.


Roger

 

[jaggedben]

In a lightening strike event it most certainly does. And again, we design these systems specifically for that millisecond that something goes wrong. If we went by the logic that "it'll be fine for 100 years," more than half of the NEC would be null and void... and more than half of the DIY crap that we regularly mock, and mock for good reason, would be justifiable.

We used to have a system without grounding electrodes at my parents place. My father always tells this story of a lightening strike in which he could see the electricity bouncing around the basement because there was no electrode. Now, I should clarify that my father likes his stories, lol... but I kinda believe him, lol.

Yeah, consider me unconvinced by your father's anecdote. You have no idea how much less the lightning would have 'bounced around' if there had been an electrode. You also have no idea what specific damage might have been worse if there had been improper connections to electrode(s), or even code-compliant but unlucky or ill-advised connections to redundant electrode(s).

By the way, shock protection and lightning protection are two totally different things. In fact, grounding can work at cross purposes with respect to each. More grounding probably always increases shock protection (although probably negligibly and not justifiably), but too much grounding and/or improperly installed grounding can cause lighting to go places that you don't want it to.

Not that I'm an expert on lightning. But here is what I know pretty well:
- A true lightning protection system, such as follows NFPA 780, is vastly different from NEC requirements.
- There have been past controversies over superstitious grounding requirements in the code. 690.47(D) was a requirement that came and went and came again and went again and thankfully has stayed gone now for two cycles. But it is is illustrative of how superstitious belief gets things into the code for no very good reason. For more you can see the video by our esteemed host:

After that video you might wonder if all the normal grounding requirements in 250 have any solid reasoning at all.
- some people seem to believe that having grounding electrodes makes lightning strikes less likely. This is poppycock.

 

[LarryFine]

Good grounding increases electrode current, and probably increases lightning strikes.

Good air-terminal installations do more to reduce strikes as well as lightning damage.

 

[electrofelon]

Watch the bit starting at 13:15. Love it, "I don't know if you've done any critical thinking......."

Makes you really lose all confidence in that ground rod ( if you had any to begin with) when you see that picture and hear what he says.

 

[Jerramundi]

@jaggedben That's fine, you can remain unconvinced. I would still argue that a system in place designed for the dissipation of a lightening strike puts you at comparatively less risk than a system with nothing in place designed for said dissipation.

I think you're taking Mike a little bit out of context here. He's talking about auxiliary electrodes and the placement of those electrodes. No where in there does he advocate for a system with NO GEC, as far as I'm aware.

 

[jaggedben]

Good grounding increases electrode current, and probably increases lightning strikes.

Good air-terminal installations do more to reduce strikes as well as lightning damage.

I highly doubt that any grounding has any effect on the likelihood of lightning strikes, whatsoever. That's like saying that grounding the neutral at the service effects the likelihood of whether there will be a hot-to-ground short on the premises. What grounding effects is the nature and severity of the damage, not the likelihood of a fault.

 

[Jerramundi]

The only "confidence" in the ground rod that I've "lost" as a result of listening to Mike, is when I gained the understanding that it does little to nothing for clearing a ground fault. In my early years I conflated the two, but not anymore thanks to Mike

 

[LarryFine]

Air terminals can indeed reduce likelihood of strikes.

Analysis of traditional lightning rods and streamer retarding air terminals

Structural Lightning Protection - This term describes what is most readily recognized as the traditional lightning rod system, with its associated bonding and grounding systems. The purpose of a traditional Ben Franklin lightning rod system is to keep the protected structure from burning down.

lightningmaster.com

 

[jaggedben]

@jaggedben That's fine, you can remain unconvinced. I would still argue that a system in place designed for the dissipation of a lightening strike puts you at comparatively less risk than a system with nothing in place designed for said dissipation.

A solitary electrode that meets NEC standards is not a 'system ... designed for the dissipation of a lightening strike'. If you want such an thing, look to NFPA 780 or another lightning-protection standard. The NEC electrode serves multiple purposes both real and supposed, and it may, if you're lucky, mitigate lightning damage from a nearby strike in a meaningful manner. To the best of my knowledge, it's probably a marginal case where it will. It's a bit of insurance that can't hurt, unless you overdo it to the point of making it worse as

What I am unconvinced of is that the NEC requirements are scientifically based.

I think you're taking Mike a little bit out of context here. He's talking about auxiliary electrodes and the placement of those electrodes. No where in there does he advocate for a system with NO GEC, as far as I'm aware.

I don't advocate no electrode either. That's a strawman. The point is that people believe that electrodes do a lot more than they really do, to the point that some people advocate for more of them when they can possibly make things worse. Note Mike's point that auxiliary electrodes never really do any good, but the code allows for them to avoid arguments with superstitious manufacturers. It makes you wonder how much it really matters that a house have two ground rods and water pipe electrode instead of just one of those things.

Here's a point: if an entire neighborhood of houses doesn't have electrodes, then the difference is grounding of the whole network is probably more significant than one house not having it. And definitely more significant than whether a single house in the neighborhood has two rods or one.

 

[jaggedben]

Air terminals can indeed reduce likelihood of strikes.

Analysis of traditional lightning rods and streamer retarding air terminals

Structural Lightning Protection - This term describes what is most readily recognized as the traditional lightning rod system, with its associated bonding and grounding systems. The purpose of a traditional Ben Franklin lightning rod system is to keep the protected structure from burning down.

lightningmaster.com

My comment was a response to your first sentence about grounding.

Also, others on this thread might note that the page you linked to doesn't focus on grounding or go into it in detail.

 

[jaggedben]

The only "confidence" in the ground rod that I've "lost" as a result of listening to Mike, is when I gained the understanding that it does little to nothing for clearing a ground fault. In my early years I conflated the two, but not anymore thanks to Mike

You should be wary, too, that it some situations it may do little to reduce shock potential to ground on a premises, unless you are standing right near it. The most pertinent situation is where you have an open service neutral. In this situation current is looking for a path from the MBJ back to the transformer grounded neutral. Some of it will go via the electrode, and it's definitely better to have an electrode in this situation. But the farther you are from it, the less it reduces the potential between bonded metal parts and the ground. Not a good time to go walking around the premises touching conduits. (Also it's not going to reduce the damage to the customers loads hardly at all.)

 

[Jerramundi]

A solitary electrode that meets NEC standards is not a 'system ... designed for the dissipation of a lightening strike'.

Now you're taking me out of context. The idea that I think of a solitary electrode as an entire system is taken hilariously out of context. I was clearly arguing that it was PART of a system designed for the dissipation of a lightening strike and I stand by that.

I've heard Mike say these words IN PERSON when clarifying that the electrode has nothing to do w/ clearing a ground fault, but is more about the dissipation of a lightening strike.

You clearly said "after that video you might wonder if all the normal grounding requirements in 250 have any solid reasoning at all." Extrapolating advocacy for no electrode is hardly a stretch from there, let alone a strawman.

Did Mike at one point rock my world when he clarified that the electrode had nothing to do w/ clearing a ground fault? Yep, absolutely and for the better. Have I ever walked away from one of his videos thinking 250 was pointless? Nope. NEVER.

 

[jaggedben]

Now you're taking me out of context. The idea that I think of a solitary electrode as an entire system is taken hilariously out of context. I was clearly arguing that it was PART of a system designed for the dissipation of a lightening strike and I stand by that.

...

And yet you haven't offered anything to quantify that dissipation, or given us any reason to believe it is real other than an undetailed anecdote from your father and an appeal to the authority of Mike Holt. I'm not saying it is not real, I'm just saying nothing in this thread really speaks to it.

(Also in my opinion, the multiple electrodes required by the NEC are no more of a 'system' than an individual one is.)

You clearly said "after that video you might wonder if all the normal grounding requirements in 250 have any solid reasoning at all." Extrapolating advocacy for no electrode is hardly a stretch from there, let alone a strawman.

I think my point was clear in the context, where I gave an example that was "illustrative of how superstitious belief gets things into the code for no very good reason." Saying 'you might wonder' is just that: maybe look into it before readily believing that the reasoning behind requirements such as supplemental electrodes, irreversible splices, and 20ft of rebar is based on anything scientific. Yes, the grounding electrodes do something. They decrease and mitigate the likelihood of damage from some causes. They never eliminate it, and it is questionable how often their mitigation is meaningful. In some cases it has surely made a tangible difference for people. But it is far from clear that the NEC requirements are derived from any kind of data-driven analysis of what is most effective. In some cases I believe they are encouraging people to go overboard in ways that make it worse.

If you look carefully at what Mike Holt says about grounding, you may notice that he advocates practices that are not required by the NEC. For example I'm pretty sure if asked he would tell you that single point grounding - one GEC - with electrodes near the service is better than grounding electrode system all over the yard. But you can read through article 250 and find nothing about that. I'm pretty sure he would tell you that running GECs over the roof is not a good idea. But the NEC allows it, and I've seen inspectors more or less force installers to do it on existing buildings.