Gmail Calendar Documents Reader Web more »
Recently Visited Groups | Help | Sign in
Google Groups Home
rec.crafts.metalworking
+ new post
About this group
Subscribe to this group
This is a Usenet group - learn more
Subpanel bonding (3-phase mains) question
Options
There are currently too many topics in this group that display first. To make this topic appear first, remove this option from another topic.
There was an error processing your request. Please try again.
flag
   14 messages - Collapse all  -  Translate all to Translated (View all originals)
The group you are posting to is a Usenet group. Messages posted to this group will make your email address visible to anyone on the Internet.
Your reply message has not been sent.
Your post was successful
 
From:
To:
Cc:
Followup To:
Add Cc | Add Followup-to | Edit Subject
Subject:
Validation:
For verification purposes please type the characters you see in the picture below or the numbers you hear by clicking the accessibility icon. Listen and type the numbers you hear
 
Mike Cook  
View profile  
 More options Nov 6, 6:02 pm
Newsgroups: sci.electronics.design, sci.electronics.misc, rec.crafts.metalworking
From: Mike Cook <mc...@NOTyahoo.com>
Date: Thu, 5 Nov 2009 23:02:25 -0800
Local: Fri, Nov 6 2009 6:02 pm
Subject: Subpanel bonding (3-phase mains) question
Reply | Reply to author | Forward | Print | Individual message | Show original | Report this message | Find messages by this author
Is it never allowed (US National Electrical Code) to bond the ground bus bar
to the neutral bus bar?

I opened a subpanel and found that both the ground bus bar and cabinet were
bonded to the neutral bus bar.

Is this allowed under any circumstance?

This is a "Y" 208/120 configuration utilizing 5 conductors in an industrial
building.

Thanks.


    Reply    Reply to author    Forward  
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
jk  
View profile  
 More options Nov 7, 6:17 pm
Newsgroups: sci.electronics.design, sci.electronics.misc, rec.crafts.metalworking
From: jk <kles...@suddenlink.net>
Date: Fri, 06 Nov 2009 23:17:38 -0800
Local: Sat, Nov 7 2009 6:17 pm
Subject: Re: Subpanel bonding (3-phase mains) question
Reply | Reply to author | Forward | Print | Individual message | Show original | Report this message | Find messages by this author

Mike Cook <mc...@NOTyahoo.com> wrote:
>Is it never allowed (US National Electrical Code) to bond the ground bus bar
>to the neutral bus bar?

>I opened a subpanel and found that both the ground bus bar and cabinet were
>bonded to the neutral bus bar.

>Is this allowed under any circumstance?

>This is a "Y" 208/120 configuration utilizing 5 conductors in an industrial
>building.

>Thanks.

Yes, ther are a number of situations where this is allowed/required
Service Entrance
Separately Derived System

jk


    Reply    Reply to author    Forward  
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
PeterD  
View profile  
 More options Nov 7, 12:08 am
Newsgroups: sci.electronics.design, sci.electronics.misc, rec.crafts.metalworking
From: PeterD <pet...@hipson.net>
Date: Fri, 06 Nov 2009 08:08:38 -0500
Local: Sat, Nov 7 2009 12:08 am
Subject: Re: Subpanel bonding (3-phase mains) question
Reply | Reply to author | Forward | Print | Individual message | Show original | Report this message | Find messages by this author
On Thu, 5 Nov 2009 23:02:25 -0800, Mike Cook <mc...@NOTyahoo.com>
wrote:

>Is it never allowed (US National Electrical Code) to bond the ground bus bar
>to the neutral bus bar?

>I opened a subpanel and found that both the ground bus bar and cabinet were
>bonded to the neutral bus bar.

>Is this allowed under any circumstance?

>This is a "Y" 208/120 configuration utilizing 5 conductors in an industrial
>building.

>Thanks.

When was it installed, and have you read the revelant sections of the
NEC?

    Reply    Reply to author    Forward  
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
bud--  
View profile  
 More options Nov 7, 1:46 am
Newsgroups: sci.electronics.design, sci.electronics.misc, rec.crafts.metalworking
From: bud-- <remove.budn...@isp.com>
Date: Fri, 06 Nov 2009 08:46:28 -0600
Local: Sat, Nov 7 2009 1:46 am
Subject: Re: Subpanel bonding (3-phase mains) question
Reply | Reply to author | Forward | Print | Individual message | Show original | Report this message | Find messages by this author

Sounds good. An example is a panel fed from a transformer.

If it is a panel fed from another panel, the neutral bar must be isolated.

A better newsgroup is probably alt.engineering.electrical.

--
bud--


    Reply    Reply to author    Forward  
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
Steve Lusardi  
View profile  
 More options Nov 8, 12:50 am
Newsgroups: sci.electronics.design, sci.electronics.misc, rec.crafts.metalworking
From: "Steve Lusardi" <stevenos...@lusardi.de>
Date: Sat, 7 Nov 2009 14:50:57 +0100
Local: Sun, Nov 8 2009 12:50 am
Subject: Re: Subpanel bonding (3-phase mains) question
Reply | Reply to author | Forward | Print | Individual message | Show original | Report this message | Find messages by this author
Yes, but only once. The rule is the safety earth is bonded to neutral at source....the distribution transformer. It is never
advisable to make this bond too far away from the transformer.because it introduces a reactance issue for high frequency noise. In
point of fact, in Europe the equalization bus must not exceed 1 meter in length. If another bond exists, ground loops are
introduced, which is another story altogether.Please also note that the same earth reference at the transformer must, at the same
point, be earthed through a ground rod or earth plane ground rod array.
Steve


    Reply    Reply to author    Forward  
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
notme  
View profile  
 More options Nov 8, 4:56 am
Newsgroups: sci.electronics.design, sci.electronics.misc, rec.crafts.metalworking, alt.engineering.electrical
From: notme <no...@notme.org>
Date: Sat, 7 Nov 2009 09:56:36 -0800
Local: Sun, Nov 8 2009 4:56 am
Subject: Re: Subpanel bonding (3-phase mains) question
Reply | Reply to author | Forward | Print | Individual message | Show original | Report this message | Find messages by this author
Is it never allowed (US National Electrical Code) to bond the ground bus bar
to the neutral bus bar?

I opened a subpanel and found that both the ground bus bar and cabinet were
bonded to the neutral bus bar.

Is this allowed under any circumstance?

This is a "Y" 208/120 configuration utilizing 5 conductors in an industrial
building.

Thanks.


    Reply    Reply to author    Forward  
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
Rich.  
View profile  
 More options Nov 8, 5:42 am
Newsgroups: sci.electronics.design, sci.electronics.misc, rec.crafts.metalworking, alt.engineering.electrical
From: "Rich." <rc...@XXcomcast.net>
Date: Sat, 7 Nov 2009 13:42:59 -0500
Local: Sun, Nov 8 2009 5:42 am
Subject: Re: Subpanel bonding (3-phase mains) question
Reply | Reply to author | Forward | Print | Individual message | Show original | Report this message | Find messages by this author

"notme" <no...@notme.org> wrote in message

news:0001HW.C71AF4D4031DC440B08A39AF@news.eternal-september.org...

No, according to the NEC  it is not allowed in a subpanel at all.

    Reply    Reply to author    Forward  
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
Ryan Evans  
View profile  
 More options Nov 8, 10:10 am
Newsgroups: sci.electronics.design, sci.electronics.misc, rec.crafts.metalworking, alt.engineering.electrical
From: "Ryan Evans" <revans48...@comcast.net>
Date: Sat, 7 Nov 2009 18:10:55 -0500
Local: Sun, Nov 8 2009 10:10 am
Subject: Re: Subpanel bonding (3-phase mains) question
Reply | Reply to author | Forward | Print | Individual message | Show original | Report this message | Find messages by this author

"notme" <no...@notme.org> wrote in message

news:0001HW.C71AF4D4031DC440B08A39AF@news.eternal-september.org...

No. As long as it is a sub-panel.
Not to be confused with a seperately-derived system(after a transformer).

RE


    Reply    Reply to author    Forward  
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
Tom Horne  
View profile  
 More options Nov 9, 6:13 am
Newsgroups: sci.electronics.design, sci.electronics.misc, rec.crafts.metalworking, alt.engineering.electrical
From: Tom Horne <horn...@gmail.com>
Date: Sun, 8 Nov 2009 11:13:41 -0800 (PST)
Local: Mon, Nov 9 2009 6:13 am
Subject: Re: Subpanel bonding (3-phase mains) question
Reply | Reply to author | Forward | Print | Individual message | Show original | Report this message | Find messages by this author
On Nov 7, 12:56 pm, notme <no...@notme.org> wrote:

> Is it never allowed (US National Electrical Code) to bond the ground bus bar
> to the neutral bus bar?

> I opened a subpanel and found that both the ground bus bar and cabinet were
> bonded to the neutral bus bar.

> Is this allowed under any circumstance?

> This is a "Y" 208/120 configuration utilizing 5 conductors in an industrial
> building.

> Thanks.

With the exception of feeders to separate buildings under previous
editions of the US NEC it is not permissible.
--
Tom Horne

    Reply    Reply to author    Forward  
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
Mike Cook  
View profile  
 More options Nov 9, 5:45 pm
Newsgroups: sci.electronics.design, sci.electronics.misc, rec.crafts.metalworking, alt.engineering.electrical
From: Mike Cook <mc...@NOTyahoo.com>
Date: Sun, 8 Nov 2009 22:45:29 -0800
Local: Mon, Nov 9 2009 5:45 pm
Subject: Re: Subpanel bonding (3-phase mains) question
Reply | Reply to author | Forward | Print | Individual message | Show original | Report this message | Find messages by this author

> With the exception of feeders to separate buildings under previous
> editions of the US NEC it is not permissible.
> --
> Tom Horne

Single building, not large (2000 sq ft?) one service entrance, one main
panel, 3 or 4 subpanels.

It looks like this bond needs to be broken...

Thanks,
Mike (OP)


    Reply    Reply to author    Forward  
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
Proteus IIV  
View profile  
 More options Nov 10, 10:08 am
Newsgroups: sci.electronics.design, sci.electronics.misc, rec.crafts.metalworking, alt.engineering.electrical
From: Proteus IIV <proteus...@gmail.com>
Date: Mon, 9 Nov 2009 15:08:06 -0800 (PST)
Local: Tues, Nov 10 2009 10:08 am
Subject: Re: Subpanel bonding (3-phase mains) question
Reply | Reply to author | Forward | Print | Individual message | Show original | Report this message | Find messages by this author
On Nov 7, 12:56 pm, notme <no...@notme.org> wrote:

> Is it never allowed (US National Electrical Code) to bond the ground bus bar
> to the neutral bus bar?

> I opened a subpanel and found that both the ground bus bar and cabinet were
> bonded to the neutral bus bar.

> Is this allowed under any circumstance?

> This is a "Y" 208/120 configuration utilizing 5 conductors in an industrial
> building.

> Thanks.

TROLL DROPPINGS

TOM LAY OFF
YOU NEVER GOT THIS RIGHT TO BEGIN WITH

I AM PROTEUS


    Reply    Reply to author    Forward  
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
Paul Keinanen  
View profile  
 More options Nov 10, 11:01 am
Newsgroups: sci.electronics.design, sci.electronics.misc, rec.crafts.metalworking
From: Paul Keinanen <keina...@sci.fi>
Date: Tue, 10 Nov 2009 02:01:20 +0200
Local: Tues, Nov 10 2009 11:01 am
Subject: Re: Subpanel bonding (3-phase mains) question
Reply | Reply to author | Forward | Print | Individual message | Show original | Report this message | Find messages by this author
On Thu, 5 Nov 2009 23:02:25 -0800, Mike Cook <mc...@NOTyahoo.com>
wrote:

>Is it never allowed (US National Electrical Code) to bond the ground bus bar
>to the neutral bus bar?

>I opened a subpanel and found that both the ground bus bar and cabinet were
>bonded to the neutral bus bar.

>Is this allowed under any circumstance?

>This is a "Y" 208/120 configuration utilizing 5 conductors in an industrial
>building.

At least in the rest of the world (=non-US), this is a typical TN-C-S
wiring case, in which the utility company 4 wire TN-C (3L+N) is
delivered to building, in which this is separated to a 5 wire TN-S
(3L+N+PE) system with separate neutral and ground.

This separation is done exactly *once*, typically at the main
entrance, after that, neutral and ground should be kept strictly
separated.

Paul


    Reply    Reply to author    Forward  
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
daestrom  
View profile  
 More options Nov 10, 1:08 pm
Newsgroups: sci.electronics.design, sci.electronics.misc, rec.crafts.metalworking, alt.engineering.electrical
From: daestrom <daest...@twcny.rr.com>
Date: Mon, 09 Nov 2009 21:08:59 -0500
Local: Tues, Nov 10 2009 1:08 pm
Subject: Re: Subpanel bonding (3-phase mains) question
Reply | Reply to author | Forward | Print | Individual message | Show original | Report this message | Find messages by this author

notme wrote:
> Is it never allowed (US National Electrical Code) to bond the ground bus bar
> to the neutral bus bar?

> I opened a subpanel and found that both the ground bus bar and cabinet were
> bonded to the neutral bus bar.

> Is this allowed under any circumstance?

> This is a "Y" 208/120 configuration utilizing 5 conductors in an industrial
> building.

When you say 'sub-panel', it may be confusing.  A step-down transformer
fed from the service entrance, that in turn feeds 208/120 to a panel is
not a sub-panel.  In that case the first panel off the transformer is
not a usual 'sub-panel' but a fed from a separately derived source (the
transformer).

You mentioned 208/120 in an 'industrial building', so I think the
building service is not 208/120 directly but may be a higher voltage and
you have a step-down transformer inside the building.

In that case, the ground/neutral *should* be bonded in the first panel
after the transformer.

Now, any other panels fed from the first panel after the step-down
transformer are true 'sub-panels' and thus should not have the ground
and neutral bonded.

So just to be clear here, are you talking about a true 'sub-panel', or
the first panel downstream of a step-down transformer?

daestrom


    Reply    Reply to author    Forward  
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
Mike Cook  
View profile  
 More options Nov 11, 6:35 am
Newsgroups: sci.electronics.design, sci.electronics.misc, rec.crafts.metalworking
From: Mike Cook <mc...@NOTyahoo.com>
Date: Tue, 10 Nov 2009 11:35:47 -0800
Local: Wed, Nov 11 2009 6:35 am
Subject: Re: Subpanel bonding (3-phase mains) question
Reply | Reply to author | Forward | Print | Individual message | Show original | Report this message | Find messages by this author

> At least in the rest of the world (=non-US), this is a typical TN-C-S
> wiring case, in which the utility company 4 wire TN-C (3L+N) is
> delivered to building, in which this is separated to a 5 wire TN-S
> (3L+N+PE) system with separate neutral and ground.

> This separation is done exactly *once*, typically at the main
> entrance, after that, neutral and ground should be kept strictly
> separated.

> Paul

Correct.

The power is delivered as 3-phase plus neutral to the building. From this --
directly, without transformer -- we have 120 "single phase" branch circuits
in the panel along with 3-wire (3 phase) circuits.

The panel I am describing (with the N & G bond) is not the main panel, so I
presume should not be bonded together.

Thanks,
Mike (OP)


    Reply    Reply to author    Forward  
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
End of messages
« Back to Discussions « Newer topic     Older topic »

Create a group - Google Groups - Google Home - Terms of Service - Privacy Policy
©2009 Google