The Sufficiency of NEC rules

[iwire]

Thanks, iwire for your reminder.

But my stand throughout the thread, I would like to bring to your kind notice, is that NEC rules are sufficient to afford protection in any situation. I am, with other members are discussing, to find out any shortcomings in the rules.

Would you like to join with us?

Join you to do what?

Your stated purpose is finding shortcomings in the rules yet you have not even hinted at what rules you feel need improvement.

It is your thread, you can continue to be as obtuse as you choose to be but in doing so there will be no improvements made to possibly deficient NEC sections.

 

[kingpb]

When discussing grounding and bonding for pools and dairy farms I do not recall anyone mentioning 680, or 547.9 and 547.10, respectively.

In the case of 547.10, providing a ground grid (equipotential plane) other than it has to be no smaller than 8 AWG; it would appear the design would require it to be engineered. Thus supported by calculations. This makes sense to me as the design for ground grids in power generating facilities is engineered, and it is the only way to attempt to eliminate step and touch potentials.

This brings me to my next point, IEEE Std 142 and 80 are a must read for designing ground systems, and again these were not mentioned in any of the previous posts nor as part of the NEC. Not expected either, because the NEC is not a design guide. These stds are read by designers and engineers.

The question - is the NEC adequate for grounding? I think it points out the areas of concern for most facilities, and in general will keep people from being injured for most types of installations. Is it sufficient to use for design, absolutely not. Post #2 points that out; the NEC even states it is not for design. Is it all inclusive to every installation, nope. Engineered systems will always be required for non-typical installs.

 

[mivey]

Join you to do what?

If you only knew the power of the dark side. Join him or all the knowledge you seek about the true nature of the NEC will be lost.

 

[Sahib]

When discussing grounding and bonding for pools and dairy farms I do not recall anyone mentioning 680, or 547.9 and 547.10, respectively.

In the case of 547.10, providing a ground grid (equipotential plane) other than it has to be no smaller than 8 AWG; it would appear the design would require it to be engineered. Thus supported by calculations. This makes sense to me as the design for ground grids in power generating facilities is engineered, and it is the only way to attempt to eliminate step and touch potentials.

This brings me to my next point, IEEE Std 142 and 80 are a must read for designing ground systems, and again these were not mentioned in any of the previous posts nor as part of the NEC. Not expected either, because the NEC is not a design guide. These stds are read by designers and engineers.

The question - is the NEC adequate for grounding? I think it points out the areas of concern for most facilities, and in general will keep people from being injured for most types of installations. Is it sufficient to use for design, absolutely not. Post #2 points that out; the NEC even states it is not for design. Is it all inclusive to every installation, nope. Engineered systems will always be required for non-typical installs.

Thanks kingpb for your reply.

The ''shortcomings'' you are mentioning really point to the insufficiency of NEC rules as regards protection of life.

But unfortunately, the discussion of this thread is not about that kind of 'insufficiency'.

It is about the sufficiency of the concepts themselves the rules talk about, e.g about the sufficiency of minimum size of 8SWG in equipotential plane.

 

[kwired]

Thanks, iwire for your reminder.

But my stand throughout the thread, I would like to bring to your kind notice, is that NEC rules are sufficient to afford protection in any situation. I am, with other members are discussing, to find out any shortcomings in the rules.

Would you like to join with us?

NEC is not perfect, if it were we would not need to edit it every three years. NEC is also not a design manual, which is a controversy at times, but it is a standard that should provide a minimum level of safety. There certainly is design practices that may take that level of safety to higher levels.

When discussing grounding and bonding for pools and dairy farms I do not recall anyone mentioning 680, or 547.9 and 547.10, respectively.

I am not going to look back, but pretty sure I have mentioned art 680 and 547 at least a time or two. There is also another thread that ended up breaking off and starting this thread, so maybe I mentioned them in that thread.

In the case of 547.10, providing a ground grid (equipotential plane) other than it has to be no smaller than 8 AWG; it would appear the design would require it to be engineered. Thus supported by calculations. This makes sense to me as the design for ground grids in power generating facilities is engineered, and it is the only way to attempt to eliminate step and touch potentials.

This brings me to my next point, IEEE Std 142 and 80 are a must read for designing ground systems, and again these were not mentioned in any of the previous posts nor as part of the NEC. Not expected either, because the NEC is not a design guide. These stds are read by designers and engineers.

Not going to disagree with your opinion, but will present you with the reality that there is no engineer (for electrical portions anyway) on most, scratch that, ALL of the Agricultural projects I can ever recall working on.

The question - is the NEC adequate for grounding? I think it points out the areas of concern for most facilities, and in general will keep people from being injured for most types of installations. Is it sufficient to use for design, absolutely not. Post #2 points that out; the NEC even states it is not for design. Is it all inclusive to every installation, nope. Engineered systems will always be required for non-typical installs.

What is typical? Ag wiring is typical for me, but maybe not for a majority of people that participate in this forum. Swimming pools are not typical for me, but in other parts of the country they maybe are.

 

[Sahib]

If you only knew the power of the dark side. Join him or all the knowledge you seek about the true nature of the NEC will be lost.

He has regarded the discussion as obtuse up to this point. It is easy to see his view on further discussion.............unless you intervene.

 

[kingpb]

kwired - You mention an engineer not being involved, which is not mandatory, but certainly someone with expertise in grounding and ground grid design, including the calculations must be involved, otherwise how do you know for certain the grounding is sufficient?

 

[iwire]

kwired - You mention an engineer not being involved, which is not mandatory, but certainly someone with expertise in grounding and ground grid design, including the calculations must be involved, otherwise how do you know for certain the grounding is sufficient?

Even if an engineer is involved how do you know for certain the grounding is sufficient?

 

[GoldDigger]

Even if an engineer is involved how do you know for certain the grounding is sufficient?

The electrons read the PE-stamped drawings and only follow designated paths.

 

[kwired]

kwired - You mention an engineer not being involved, which is not mandatory, but certainly someone with expertise in grounding and ground grid design, including the calculations must be involved, otherwise how do you know for certain the grounding is sufficient?

Understood, now add cost of that to the project and somebody else gets the job.

 

[rbalex]

Even if an engineer is involved how do you know for certain the grounding is sufficient?

Sorta like, "How do you know having a licensed surgeon involved with that appendectomy is sufficient." Legal certification, whatever the form, is no more a guarantee for electricians than for engineers - or any other certified or degreed profession.

 

[iwire]

Legal certification, whatever the form, is no more a guarantee for electricians than for engineers - or any other certified or degreed profession.

That was what I was trying to point out and in the case of lightning protection which was touched upon in this thread I don't believe anyone can decide what is sufficient with any real degree of certainty.

 

[Sahib]

That was what I was trying to point out and in the case of lightning protection which was touched upon in this thread I don't believe anyone can decide what is sufficient with any real degree of certainty.

Sufficient with certainty for the time being as regards NEC rules in particular and scientific laws of nature in general.

 

[Sahib]

''250.4(A)(4) Bonding of electrically conductive materials and other equipment. Normally non-current-carrying electrically conductive materials that are likely to become energized shall be connected together and to the electrical supply source in a manner that establishes an effective ground-fault current path.''

On the above the comment by Don as regards bonding of a balcony railing is given below

I think to require the railing to be bonded is a huge stretch of the code rule. Even if electrical equipment is used on the railing, it is really unlikely, that the railing will become energized.

From the question, this appears to be a dwelling unit, and the 2011 code requires a receptacle outlet if the balcony can be accessed from inside the unit.

My comment is as follows.

The balcony railing is extraneous metal. Suppose the normally non-current-carrying electrically conductive material of the receptacle becomes energized. If there is a possibility of touching it and the balcony railing simultaneously, there is a risk of electrocution in spite of the fact that the balcony railing is not energized in this case. So bonding of railing is required in such cases.

I do not know which code rule supports it other than 250.4(A)(4) so that I could say the NEC rules covered this case also.

 

[kwired]

The balcony railing is extraneous metal. Suppose the normally non-current-carrying electrically conductive material of the receptacle becomes energized. If there is a possibility of touching it and the balcony railing simultaneously, there is a risk of electrocution in spite of the fact that the balcony railing is not energized in this case. So bonding of railing is required in such cases.

I do not know which code rule supports it other than 250.4(A)(4) so that I could say the NEC rules covered this case also.

If that railing is insulated from ground where is the voltage to cause an electrocution risk coming from?

If that railing is grounded, and you bring same accidentally energized normally non current carrying component within reach you will have a much higher risk of electric shock.

Now touch the grounded railing with the energized object and if impedance is low enough you supposedly open an overcurrent device, maybe with a little fireworks show as a bonus.

 

[Sahib]

If that railing is insulated from ground where is the voltage to cause an electrocution risk coming from?

For the sake of argument, let it be grounded.

If that railing is grounded, and you bring same accidentally energized normally non current carrying component within reach you will have a much higher risk of electric shock.

Let us not forget about bonding.

Now touch the grounded railing with the energized object and if impedance is low enough you supposedly open an overcurrent device, maybe with a little fireworks show as a bonus.

The duration of operation of OCPD may cause problems.

By the way,You did not state the relevant code rules I requested you.

 

[jim dungar]

The NEC does not say 'possibly' it specifically says 'likely'.
I think you should look at a thesaurus, or a Merriam-Webster dictionary as the NFPA suggests for undefined terms.

How does your argument stand up, if you sustitute a different piece of extraneous metal?

Your belt buckle is extraneous metal. Suppose the normally non-current-carrying electrically conductive material of the receptacle becomes energized. If there is a possibility of touching it and your belt buckle simultaneously, there is a risk of electrocution in spite of the fact that your belt buckle is not energized in this case. So bonding of belt buckle is required in such cases.

I do not know which code rule supports it other than 250.4(A)(4) so that I could say the NEC rules covered this case also.

 

[Sahib]

Jim:
Your substitution i.e belt buckle does not make sense to me, when it is worn by the person concerned.
By the way you mean the same article 250.4(A)(4) also covers the case under consideration. Isn't?

 

[rbalex]

That was what I was trying to point out and in the case of lightning protection which was touched upon in this thread I don't believe anyone can decide what is sufficient with any real degree of certainty.

Sorry I missed your response earlier.

I have to chuckle a bit. There was a period where the NFPA withdrew Standard 780 (lightning protection) as a response to not recognizing lightning protection systems other than the "Franklin rod" for lack of "scientific investigation" for the alternate methods. The proponents of the alternate system threatened a "restraint of trade" suit, asserting that Franklin rods had no more scientific basis. A working committee chaired by Dick Biermann, former NEC TCC Chair and currently member emeritus, acknowledged that substanitive material was unavailable at the time. As I recall, it took about a year and a half to reinstate NFPA 780.

 

[kwired]

For the sake of argument, let it be grounded.

Let us not forget about bonding.


The duration of operation of OCPD may cause problems.

By the way,You did not state the relevant code rules I requested you.

If it were grounded there is not much of an argument:?

Bonding is what we are discussing how are we supposed to forget about it:?

What rules do you want that have not already been mentioned?