Bonding
- Thread starter dyanchik
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ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: Bonding
Bonding at a "sub-panel" would cause the grounded conductor and equipment grounding conductor to be installed in parrallel, therefore you would have nuetral current flowing on the EGC.
250.24(A)(5), 250.6
[ May 28, 2004, 09:23 AM: Message edited by: ryan_618 ]
Bonding at a "sub-panel" would cause the grounded conductor and equipment grounding conductor to be installed in parrallel, therefore you would have nuetral current flowing on the EGC.
250.24(A)(5), 250.6
[ May 28, 2004, 09:23 AM: Message edited by: ryan_618 ]
- Location
- Massachusetts
Re: Bonding
Well....because it is code.
Short answer is if you bond twice, say at the service and at a downstream panel you will have created a parallel path for the unbalanced neutral current.
Current that should only be using the neutral conductor will split and use both any grounding paths and the neutral conductor back to the next bonding point.
This could be a potential shock or fire hazard.
Well....because it is code.
Short answer is if you bond twice, say at the service and at a downstream panel you will have created a parallel path for the unbalanced neutral current.
Current that should only be using the neutral conductor will split and use both any grounding paths and the neutral conductor back to the next bonding point.
This could be a potential shock or fire hazard.
ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: Bonding
Good answer Bob!!! You rule.
Good answer Bob!!! You rule.
stars13bars2
Senior Member
Re: Bonding
Could it be because everyone is an electrician that it is so common to see this. The part that causes me more concern is the number of times that I find this in large panelboards with bolt in breakers that the homeowner or maintenance man didn't install. If they get this simple application wrong,it causes me to wonder what other violations and dangers may be lurking in their system.
Could it be because everyone is an electrician that it is so common to see this. The part that causes me more concern is the number of times that I find this in large panelboards with bolt in breakers that the homeowner or maintenance man didn't install. If they get this simple application wrong,it causes me to wonder what other violations and dangers may be lurking in their system.
pierre
Senior Member
- Location
- Westchester County, New York
Re: Bonding
Stars
I believe you have hit on a subject that is haunting our industry. The speed factor for installations and the shortage of manpower coupled with the absence of proper education has created a 'monster' for our industry. You are correct in seeing this and other problems - especially when a person answers " that is the way I have always done that". How can and will this be changed. It can start by making continuing education mandatory. I know I am an instructor and that would help my business... but I got into the teaching end because I want to try and help this situation.
That is how I see what is happening to our great industry and change is needed.
Pierre
Stars
I believe you have hit on a subject that is haunting our industry. The speed factor for installations and the shortage of manpower coupled with the absence of proper education has created a 'monster' for our industry. You are correct in seeing this and other problems - especially when a person answers " that is the way I have always done that". How can and will this be changed. It can start by making continuing education mandatory. I know I am an instructor and that would help my business... but I got into the teaching end because I want to try and help this situation.
That is how I see what is happening to our great industry and change is needed.
Pierre
Re: Bonding
Here is a different perspective I have witnessed. A lot of equipment manufactures demand that the N-G voltage be kept to 2 VRMS or lower, which equates to a 3.3% voltage drop. So what the site tech or electrician will do, as you already know, is bond the N-G in a sub-panel or at the receptacle, rather than addressing the real problem of voltage drop. May solve the problem for a particular piece of equipment, but ends up corrupting the distribution system.
Here is a different perspective I have witnessed. A lot of equipment manufactures demand that the N-G voltage be kept to 2 VRMS or lower, which equates to a 3.3% voltage drop. So what the site tech or electrician will do, as you already know, is bond the N-G in a sub-panel or at the receptacle, rather than addressing the real problem of voltage drop. May solve the problem for a particular piece of equipment, but ends up corrupting the distribution system.
hbiss
EC, Westchester, New York NEC: 2014
- Location
- Hawthorne, New York NEC: 2014
- Occupation
- EC
Re: Bonding
Right. And then, instead of a voltage differential between the neutral and ground you will have the voltage differential present between the case of the equipment and the plumbing, building steel etc. This can present a shock hazard to anyone making contact between the two.
-Hal
Right. And then, instead of a voltage differential between the neutral and ground you will have the voltage differential present between the case of the equipment and the plumbing, building steel etc. This can present a shock hazard to anyone making contact between the two.
-Hal
Ed MacLaren
Senior Member
Re: Bonding
Ed
Dyanchic, this sketch may help illustrate the principle involved.
Ed
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