Bonding the UFER

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mbrooke said:
Irregardless of being designated an earth electrode or not, this is definitely one way steal can become energized.
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I have a table lamp sitting on top of a metal filing cabinet. Conceivable I could close the cord in the drawer and energize the cabinet.

Should the NEC require bonding of metal furniture or should I just receive a Darwin award and the rest of the world gets on with their lives?


BTW, that rule is not about structural steel, its wall framing.
 
iwire said:
I have a table lamp sitting on top of a metal filing cabinet. Conceivable I could close the cord in the drawer and energize the cabinet.

Should the NEC require bonding of metal furniture or should I just receive a Darwin award and the rest of the world gets on with their lives?


BTW, that rule is not about structural steel, its wall framing.
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True, but this proves my point, it should not matter if building steal is an electrode or not, it should be bonded. Why do we bond water pipes then?
 
jumper said:
How the heck did a thread go from ufers to open noodles energizing filing cabinets?:blink:
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Because all 3 are inter related, just haven't made the connection yet :D :p Seriously, we are about to get into spheres of potential :lol::thumbsup:
 
mbrooke said:
In theory yes... but there is this: will your filing cabinet become energized during an open neutral?
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Hold on, try to focus.

You were hanging your hat on the appliance installer getting electrocuted by the metal studs as proof building steel should be grounded. That incident had nothing to do with neutrals.


mbroke said:
True, but this proves my point, it should not matter if building steal is an electrode or not, it should be bonded. Why do we bond water pipes then?
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So I asked you about my filing cabinet and you jump back to open neutrals.


In theory yes... but there is this: will your filing cabinet become energized during an open neutral?
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My point is simply this, we cannot protect against every possibility.

Dependent on where the human is and where the neutral opens, bonding anything to the neutral can hurt as much as help.

You mentioned plumbing, yes we bond it, and when I am in the shower that may save me.

When I standing on wet ground shutting off my outside hose faucet that bonding may kill me.
 
iwire said:
Hold on, try to focus.

You were hanging your hat on the appliance installer getting electrocuted by the metal studs as proof building steel should be grounded. That incident had nothing to do with neutrals.
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Again, 100% correct. However, an open neutral is simply one more way (out of several others) in which a metal stud or frame could become energized.


So I asked you about my filing cabinet and you jump back to open neutrals.
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Yes, because there would be less need to bond a filing cabinet because the risk is lower:

A. Filing cabinet energizing risk:

1. Local lamp cord may get pinched in the door.

B. Building steal energizing risk:

1. Hundreds of not thousands of square feet of wire that could enrgize a stud at any point

2. Open neutral

3. MV falling into LV on the pole.


My point is simply this, we cannot protect against every possibility.
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Of course, but we can go after the most likely ones. Thats what they did with pools, but guess what, misunderstanding showed its head when it first happened and I still think it does... I will post two vids explaining this.

Dependent on where the human is and where the neutral opens, bonding anything to the neutral can hurt as much as help.
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That is true, but if everything is bonded together, mainly the major components a person is likely to be in contact with (like a floor with rebar), the risk is reduced.

Bonding only one side or failing to bond the stair into a pool can be dangerous, but once both rails are bonded with everything else it becomes safe.


You mentioned plumbing, yes we bond it, and when I am in the shower that may save me.
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Of course, what if the metal drain is bonded but not you water supply lines, or visa-versa?

When I standing on wet ground shutting off my outside hose faucet that bonding may kill me.
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Of course, that is correct. But unbonding plumbing creates a bigger risk only because a person is more likely to be inside the structure when touching plumbing then outside. This is a spot where we play Russian roulette where we have to take the pistol with the fewest bullets in the chamber.
 
Here are two videos that basically say what Ive been trying to say. My theory is that the CMP were misinformed, once believing that grounding provided all safety and as a result had been originally writing everything in article 250 around that myth which is now the foundation of article 250 as we know today. My theory is that much of the myths are still being carried on with gaping holes in bonding requirements and over emphasis in grounding electrodes.



4:53

https://www.youtube.com/watch?v=WlnFNTay-9Q#t=309


1:06:53:

https://www.youtube.com/watch?v=mpgAVE4UwFw
 
mbrooke said:
Yes, because there would be less need to bond a filing cabinet because the risk is lower:

A. Filing cabinet energizing risk:

1. Local lamp cord may get pinched in the door.

B. Building steal energizing risk:

1. Hundreds of not thousands of square feet of wire that could enrgize a stud at any point

2. Open neutral

3. MV falling into LV on the pole.
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I am going to consider this a non-response. :D



Of course, but we can go after the most likely ones
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BINGO!!! But you have not shown it is likely only that it is possible.


That is true, but if everything is bonded together, mainly the major components a person is likely to be in contact with (like a floor with rebar), the risk is reduced.
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So now you have made the jump from bonding building steel to making the entire structure an equal potential grid. :D Now the mailman walks up to my home, grabs the railing and gets knocked on his butt. Maybe a grounding mat for my yard is needed as well. :D

Using the pool example that you seem to like, my cabinet would have to be bonded.

Bonding only one side or failing to bond the stair into a pool can be dangerous, but once both rails are bonded with everything else it becomes safe.
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No kidding, I thought we already established both of us understand difference of potential.:)









But unbonding plumbing creates a bigger risk only because a person is more likely to be inside the structure when touching plumbing then outside.
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See this is what drives me nuts. ::D You say opinions and guesses like they are rock solid facts. There are so many variables it is next to impossible to determine which is the bigger hazard.


If you want the code to change you would have to provide more than 'its possible' 'it might happen'. IMO you will need to find and provide data showing the need, not theory or good intentions, data. :)
 
iwire said:
I am going to consider this a non-response. :D
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I take you do not work well with probability?


BINGO!!! But you have not shown it is likely only that it is possible.
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I think open neutrals are common enough that extra care should be taken to guard against them or at least thier effects. In any case it seems to violate the NEC's n+2 redundancy like style.

Picture this: For a person to be shocked at least two (now three) contigncies must first take place:

1. A fault in an NRTL listed appliance. A new appliance must pass leakage current tests and other requirements.

2. The failure of the EGC

3. The failure of the GFCI

For an over current fire:

1. A condition causing over current

2. Failure of the OCPD.

This is just two examples out of many.

An open neutral hazard:

1. A break in the neutral.

Bonding metal water pipes eliminates the risk of potential between a sink and say the fridge, but what about the floor? Walls? See whats happening?



So now you have made the jump from bonding building steel to making the entire structure an equal potential grid. :D
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Yes, because when you bond all extraneous metal within a structure you automatically create an equal potential mesh. We do not build a steal or wire cage around a pool, we just bond the metal


Now the mailman walks up to my home, grabs the railing and gets knocked on his butt. Maybe a grounding mat for my yard is needed as well. :D
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Well, again, the risk is greater to the lady washing dishes with wet hands then a mail guy in shoes and dry hands.

Using the pool example that you seem to like, my cabinet would have to be bonded.
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In theory yes, but less need to. Much less chance of energization.


No kidding, I thought we already established both of us understand difference of potential.:)
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But sometimes you make statements that make me wonder.








See this is what drives me nuts. ::D You say opinions and guesses like they are rock solid facts. There are so many variables it is next to impossible to determine which is the bigger hazard.


If you want the code to change you would have to provide more than 'its possible' 'it might happen'. IMO you will need to find and provide data showing the need, not theory or good intentions, data. :)[/QUOTE]
 
mbrooke said:
I take you do not work well with probability?
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[/QUOTE]

The problem is you are not using any facts, you are simpley making assumptions.

That is no way to write code.

I have some errands to do, I will keep reading from my phone but to tough to make quotes with.
 
iwire said:
The problem is you are not using any facts, you are simpley making assumptions.

That is no way to write code.

I have some errands to do, I will keep reading from my phone but to tough to make quotes with.
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Take pics of any good electrics on the way, I need my eye candy :) :p


IMO I do not believe they are assumptions because imo the whole point of bonding is not to gain grounding electrodes but rather an equal potential mesh, or at least one having the ability to trip a breaker on a fault.

If we bond plumbing to reduce fire and shock, we must do so for others.
 
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mbrooke said:
What is your experience in that? I think you would contribute a lot to the discussion.
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Cattle either loosing weight because they aren't drinking water, and/or lowered milk production Mr MBrooke

The internal influences can be mitigated by bonding ,ergo the equal potential in art 547, (or 680 if you will)

This works to an extent , because the earth conducts , electric fences being a notorious culprit.

The external influences would be the entire poco infrastructure's MEN . Yes they can install isolators , but they only work IF any given equopotential plane is distal from the next one.

Fact is, the closer one drives a GEC to a substation, the more likely it is an earthed noodle....:)

If we want to truly examine our GEC's ,UFERS, or what some (thankfully) call Earthing, we need to consider the different styles OF earthing out there

~RJ~
 
romex jockey said:
Cattle either loosing weight because they aren't drinking water, and/or lowered milk production Mr MBrooke
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Its typical from everything I have read. Apparently something as low as 1 volt can irritate them.


The internal influences can be mitigated by bonding ,ergo the equal potential in art 547, (or 680 if you will)

This works to an extent , because the earth conducts , electric fences being a notorious culprit.

The external influences would be the entire poco infrastructure's MEN . Yes they can install isolators , but they only work IF any given equopotential plane is distal from the next one.
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True, and in fact the best solution for external influences (if you are lucky) is to simply dispose of the MGN (MEN) along with any other bonded utilities the whole route up to the farm. This is often done by setting down a a 7.2 to 2.4kv step down transformer and running the 2.4kv secondary on insulators up to the farm property with double bushing 2.4kv - 120/240 transformers on the pole or pad mount.

In reality few POCOs are willing to do that the only way to "fix" the issue is to isolate everything including water and gas while making an equal potential grid.

But none the less this proves my point: its bonding, not earthing that protects the cattle.

Fact is, the closer one drives a GEC to a substation, the more likely it is an earthed noodle....:)
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Trust me, this can happen anywhere. In some cases the earth current is actually less near substations with the 3 phase power cancelling out, but even then Id say your correct.

If we want to truly examine our GEC's ,UFERS, or what some (thankfully) call Earthing, we need to consider the different styles OF earthing out there

~RJ~
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I agree. I have some graphics which will add a twist.
 
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