Bonding screw

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patpappas

patpappas

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What issues could occur from installing the bonding screw at each panel after bonding the first from a separately derived system, I was taught the first panel from a separately derived system has the bond srew or strap installed and that was that, when asked whats the difference if the main panels and sub-panels are bonded, I assumed creating a different potential in grounding possibly but know I am not sure if that is right.
 
Just remember the grounded conductor (neutral), and the grounding conductor (green or bare). Must be isolated from each other after the first disconnect.:wink:
The equipment grounding conductor must be isolated from the neutral. Because some times the neutral will shock you. It carries a load back to the source.
The equipment ground is to assure the equipment does not become energized.
 
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Give Mike's G v B section an eyeballing:
http://www.mikeholt.com/freegraphics.php?id=gvb


If you PM me your email address, I will send you a Power Point Presentation on the objectionable current also.
 
Normally operating currents are intented to flow on insulated and isolated parts and materials. By rebonding the grounded conductor on the load side of the service disconnecting means, normally operating current can and will flow on ANY path back to the source, including through a person, or through a conductive material in contact with a combustible material.
 
Anybody know why it is legal to use metal pipe between a meter and a panelboard. Both the panelboard and meter are bonded so wouldn't the metal pipe create a parallel path????
 
480sparky said:
Word on the street is parts of NJ requires 'em. :cool:
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A vicious rumor!
:D

From what I have heard :roll:...there are a couple of EI's in Middlesex County "attempting" to enforce it.
Speaking to an EI I am familiar with, a letter from the State "should" have gone out to all Building Depts. denying the need for a Kenny Clamp.

I have never installed one, but I do have a 1/2 dozen on a shelf. :smile:


...maybe I'll email the State and get an answer.....anyone want to enter a breath holding contest with me :grin:
 
Dennis Alwon said:
Anybody know why it is legal to use metal pipe between a meter and a panelboard. Both the panelboard and meter are bonded so wouldn't the metal pipe create a parallel path????
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For whatever reason, the code permits/requires as many parallel paths as you would like on the line side of service disconnecting means...
 
bphgravity said:
For whatever reason, the code permits/requires as many parallel paths as you would like on the line side of service disconnecting means...
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I know this has been brought up many times before, and I can't recall if an answer as to the "why" of that has ever been presented.

My gut instinct tells me the code allows it because of the high available fault current on the line side of a service disconnect. But I could be totally wrong. :)
 
celtic said:
A vicious rumor!


From what I have heard :roll:...there are a couple of EI's in Middlesex County "attempting" to enforce it.
Speaking to an EI I am familiar with, a letter from the State "should" have gone out to all Building Depts. denying the need for a Kenny Clamp.....
Click to expand...

Oh, really?

celtic said:
...maybe I'll email the State and get an answer.....anyone want to enter a breath holding contest with me :grin:
Click to expand...

I'll take that wager. I'm full of hot air to begin with.
wink3.gif
 
peter d said:
I know this has been brought up many times before, and I can't recall if an answer as to the "why" of that has ever been presented.

My gut instinct tells me the code allows it because of the high available fault current on the line side of a service disconnect. But I could be totally wrong. :)
Click to expand...


Let's look at from a point of potential hazards, shock and fire.

From a shock standpoint, the return path on the line of side of the service is intentionally designed to be of significantly low resistance. Thus, only a limited amount of normally operating current should be present on the exposed metals parts and grounding systems. If one were to determine objectionable is present on the grounding system, Section 250.6 identifies ways of avoiding it. This is the entire purpose for 250.6

On the load side of the service, we don't have as robust return paths. It is conceivable that an alternate return path could be present with sufficiently low enough resistance to present shock hazard. This is where users of electricity are MOST likely to be in contact with electrically conductive and electrically operated equipment.

From a fire standpoint, normally operating current on the line side of the service is typically not in the presence of combustible materials. On the load side of the service, it is very typical for expose metal parts and other grounded parts of the system to be in contact with combustible materials.

This is why the rule exists..
 
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