Is the design of circuit breaker boxes incorrect for lightning strikes? Watching Mike's video.

[ericsarratt]

I have been watching Mike Holt's video on Grounding, System and Equipment [250.4, 2020 NEC].

In the video he says that lightening travels so fast that it doesn't take curves well because of skin effect. As a result of this, it is best to avoid unnecessary bends and loops in the grounding wire.

Here is the video:

However, in electrical circuit breaker panels some electricians put in drip loops (really a bend) in the ground wires. They also create right angles with the 6AWG wire which goes to the grounding rod (to make it neat and pretty).

Given this nature of lightening, shouldn't the grounding wire which goes to the ground rod be attached vertically at the bottom of the grounding bar? Then the wire should go straight out the bottom of the box and straight to the grounding rod?

 

[ericsarratt]

Post continued....

If I am following Mike's comments correctly, here is an example of a not-so-good electrical panel.



And this one is better, but still there is a bend of the grounding wire.

Wouldn't shooting straight out the bottom of that grounding bar be better?

Thank you for your comments and thoughts.

 

[infinity]

You've mentioned the words "grounding wire" several times do you really mean the grounding electrode conductor (GEC) or something else?

 

[ActionDave]

If you want to obsess over details that have .000000001% payoff go ahead. I'm going to route a Grounding Electrode Conductors out of my way and back in the corners of my panels.

Edit to add. I went and watched the video. You seem to have focused in on what Mike says at 20:00 min. I think you missed the part less than a minute later where he asks the whole panel what they think about system grounding (meaning the connection to earth) and they all agree it doesn't do that much and none of what it does is inconsistent. Important to remember the topic is about what I would call earthing and not equipment grounding.

 

[ericsarratt]

You've mentioned the words "grounding wire" several times do you really mean the grounding electrode conductor (GEC) or something else?

Ooops. Crap. I did it again. Yes, I meant grounding electrode conductor (GEC).

I am still learning and new with the correct terminology.

 

[hillbilly1]

I’m surprised nobody has mentioned the missing bond bushing and other violations in the first picture. Was that inspected?

 

[infinity]

I’m surprised nobody has mentioned the missing bond bushing and other violations in the first picture. Was that inspected?

There could be a bonding locknut but you're probably right about the lack of "extra" bonding on the service raceway. What else do you see?

 

[Tulsa Electrician]

As long as you learn that's what is key. I would say yes he was referring to the GEC. If you watching the video take time to open your book and read part 3 of 250.
Grounding Electrode system and Grounding Electrode Conductor.

Watch the video read than rewatch pausing to relate to book.

Now when you ask about this you can use good terms. A helpful item to do when you discuss article 250 is go to figure 250.1 look at the pic and go there. You can also go to table 250.3 for other related articals. I find it most helpful.

Now for your question related to the video. Try to find the FPN that mentions this in artical 250. Remember FPN are not enforceable.
I will give you a hint. Start at the beginning of 250 looking for FPNs.

As you read find the FPN for spacing on rod type electrodes. These FPN do make sense just not enforceable.

I look forward to your next question.

 

[jim dungar]

This is an issue with surge currents not general fault currents at 60Hz.
Bends are bad in the "down leads" from lighting rods.
Bends are bad in surge suppressor leads.
Bends are not a concern in grounding electrode conductors from the system neutral bonding point.

 

[ericsarratt]

I’m surprised nobody has mentioned the missing bond bushing and other violations in the first picture. Was that inspected?

Those are just picture examples I found online that clarified my point.

 

[ericsarratt]

I see a problem that happened. I meant for the video to cue at 18:50. I will also put the time in for the video from now on.

 

[ericsarratt]

As long as you learn that's what is key. I would say yes he was referring to the GEC. If you watching the video take time to open your book and read part 3 of 250.
Grounding Electrode system and Grounding Electrode Conductor.

Watch the video read than rewatch pausing to relate to book.

Now when you ask about this you can use good terms. A helpful item to do when you discuss article 250 is go to figure 250.1 look at the pic and go there. You can also go to table 250.3 for other related articals. I find it most helpful.

Now for your question related to the video. Try to find the FPN that mentions this in artical 250. Remember FPN are not enforceable.
I will give you a hint. Start at the beginning of 250 looking for FPNs.

As you read find the FPN for spacing on rod type electrodes. These FPN do make sense just not enforceable.

I look forward to your next question.

I'll re-watch the video with my NEC book and your suggestions. Thanks.

 

[ActionDave]

I see a problem that happened. I meant for the video to cue at 18:50. I will also put the time in for the video from now on.

Fine, start at 18:50 just don't stop till you get past 20:50 where the whole panel nods in agreement that system earthing is of marginal value. Dirt Worshipers don't like to hear this.

 

[ericsarratt]

Fine, start at 18:50 just don't stop till you get past 20:50 where the whole panel nods in agreement that system earthing is of marginal value. Dirt Worshipers don't like to hear this.

Okay.

I do appreciate all the help and feedback. I only recently started specifically studying electricity. I am in HVAC school, but it wasn't until I looked into electrical that HVAC started making sense to me.

I think looking at electrical gave me a broader perspective whereas HVAC was to microoriented for me to wrap my head around, there wasn't enough knowledge of how electricity works.

I can "do" things with electrical wiring, but understanding it really helps.

 

[ActionDave]

Okay.

I do appreciate all the help and feedback. I only recently started specifically studying electricity. I am in HVAC school, but it wasn't until I looked into electrical that HVAC started making sense to me.

I think looking at electrical gave me a broader perspective whereas HVAC was to microoriented for me to wrap my head around, there wasn't enough knowledge of how electricity works.

I can "do" things with electrical wiring, but understanding it really helps.

I'm not trying to beat you up, I'm just on a mission to destroy the lies of the Dirt Worshipers that exist in the building world. Circuitry, theory, and good construction habits are what matters. I could care less about ground rods and the wires that connect them.

 

[jaggedben]

@ericsarratt
I think you should recognize a few things:
1) A direct or very close by lightning strike is going to cause damage, period. That is, unless you have an actual Lightning Protection System, which is a whole scope of expertise and code outside the NEC and normal electrical installation.
2) Proper NEC grounding may provide some protection or mitigation from lightning damage at some distance from a strike.
3) NEC requirements are not designed around lightning alone, and in some cases may make things worse with regard to lightning in particular.

I agree with others that things like wire bends aren't worth obsessing over. There's possibly possibly thin area between (1) and (2) above where it might make a difference, but you will never know in any particular instance if it made a difference or if the strike was too close or too far for it to make a difference. Pay more attention to things like bringing all electrodes to a single GEC, and not having electrodes 'all over the yard'. And don't add auxiliary electrodes if you can talk people out of it.

 

[LarryFine]

Remember that all of the other conductors in the current pathway from outside matter, too.

 

[Another C10]

the grounding electrode conductor may need to be a #4 if that's a 200A panel.

 

[Another C10]

the grounding electrode conductor may need to be a #4 if that's a 200A panel.

besides if that wall remains open theres a duplex that will get covered and some romex needs strapping plus the romex is not allowed normally to be accessible to damage as it presently is.

not to mention the looped feeders tend to promote inductance so I've been told.

 

[hillbilly1]

I recently went out on a strike that hit an unused wood utility pole, went across the ground, hit the corner of a newly poured concrete slab, come out of the slab, hit two extension cords, travel across the road, disintegrated the gfi receptacle and box, then out to the poco transformer destroying their protector and blowing the transformer jack out. Brand new service and SPD. Not much is going to stop a direct hit!