# Separation of Neutral and Ground bar?



## PDX-SPARKY (Mar 5, 2010)

Hey guys, I am new to the site, and as an apprentice (1st Yr.) I am always asking questions. So I've asked my Journeyman and teacher @ school yet I still have a tough time remembering why, in a sub panel that lets say is in a detached garage or shop you need to seperate the Ground and nuetral bar. I am still a little confused as to why. I know it needs to be done, I just am looking for the purpose just for knowing it.


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## NolaTigaBait (Oct 19, 2008)

To prevent objectionable current. The only place you bond the neutral/ground is at the service.


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## nolabama (Oct 3, 2007)

Seperate buildings may (but prollay not in your case) indicate a new source. If so you bond again. 

Whats up with the thank you stuff??


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## JohnJ0906 (Jan 22, 2007)

PDX-SPARKY said:


> Hey guys, I am new to the site, and as an apprentice (1st Yr.) I am always asking questions. So I've asked my Journeyman and teacher @ school yet I still have a tough time remembering why, in a sub panel that lets say is in a detached garage or shop you need to seperate the Ground and nuetral bar. I am still a little confused as to why. I know it needs to be done, I just am looking for the purpose just for knowing it.


Welcome! :thumbsup: Asking questions is the way to learn.

PDX, think of it this way - the only place the neutrals and EGCs are connected is at the main service entrance, and at separately derived systems. Everywhere else they are separate. Devices, subpanels, junction boxes, etc. Neutrals carry current, and we don't want that current on the EGCs, metal conduits, metal piping, etc.

Now, do you know why the neutral and grounds are connected at the main service?


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## PDX-SPARKY (Mar 5, 2010)

JohnJ0906 said:


> Now, do you know why the neutral and grounds are connected at the main service?


Well, honestly I don't really know. :confused1:

Does it have to do with the utility being grounded at the transformer, and at other locations?


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## Forgery (Mar 6, 2010)

PDX-SPARKY said:


> Well, honestly I don't really know. :confused1:
> 
> Does it have to do with the utility being grounded at the transformer, and at other locations?


It's to give a path back to allow the OCPD to do it's job. I had a really good power point presentation on this but I lost it. I'll try to find it for you.


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## charlie Bob (Jul 26, 2009)

NolaTigaBait said:


> To prevent objectionable current. The only place you bond the neutral/ground is at the service.


I'd stick to this one.
Ol' NolaTigaBait summed it up for you.


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## jwjrw (Jan 14, 2010)

By bonding at both places you allow 2 paths that voltage can take back to the service and you only want 1 path. That maybe over simplifying it but basically what it means.


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## Forgery (Mar 6, 2010)

Try this link: http://www.tirebiter.net/downloads/grounding_presentation.ppt


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## 220/221 (Sep 25, 2007)

Ask yourself "where does the current go if you "lose" the neutral?

Draw a picture and you will find that it may potentially go (among other places) thru the metal garage door via the ground pin on the door opener.


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## RIVETER (Sep 26, 2009)

220/221 said:


> Ask yourself "where does the current go if you "lose" the neutral?
> 
> Draw a picture and you will find that it may potentially go (among other places) thru the metal garage door via the ground pin on the door opener.


We had a child here, locally, killed because of this.


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## PDX-SPARKY (Mar 5, 2010)

Thanks for all the replies, I am getting a good picture of what is happening now.

Forgery... Thanks for the link to the Ppt.:thumbsup:


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