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#124791 - 12/17/06 12:36 AM Floating Neutral  
Admin  Offline

Administrator
Member
Joined: Oct 2000
Posts: 3,458
NY, USA
Quote
College campus in DC. This defines "floating" neutral. Will be fixed next week.

- VAElec
[Linked Image]

[Linked Image]


Tools for Electricians:

#124792 - 12/18/06 05:08 PM Re: Floating Neutral  
Trumpy  Offline


Member
Joined: Jul 2002
Posts: 8,223
SI,New Zealand
Wow!,
I don't like the look of this at all. [Linked Image]


#124793 - 12/18/06 05:42 PM Re: Floating Neutral  
Luketrician  Offline
Member
Joined: Jul 2006
Posts: 272
Sale Creek, TN USA
???? Whaa????? [Linked Image]


Luke Clarke
Electrical Planner for TVA.


#124794 - 12/18/06 10:37 PM Re: Floating Neutral  
mxslick  Offline
Member
Joined: Oct 2004
Posts: 803
Atomic City, ID USA
I'm having a bit of trouble getting a grip on this....in pic#1 , on the right side, the silver tab behind the neutral bus..it that a line lug? Or the support post for the deadfront?

And if not, if it is as I think it appears to be, just the support for the neutral bus, why didn't the OP simply put a nut driver on the screws on the spot and fix it? I don't mean to be rude and I hope no one takes what I just said that way, but I think something's missing in the info on this one...

I do agree that it is indeed a big problem though, that floating bus will eventually get in trouble... [Linked Image]

[This message has been edited by mxslick (edited 12-18-2006).]


Stupid should be painful.

#124795 - 12/20/06 05:40 AM Re: Floating Neutral  
e57  Offline
Member
Joined: May 2003
Posts: 2,876
S.F.,CA USA
From the appearance of the treads on the screws thay dont seem to be an \electrical connection -just the neutral bar dangling there. (Physicaly Floating)


Mark Heller
"Well - I oughta....." -Jackie Gleason

#124796 - 12/20/06 07:26 AM Re: Floating Neutral  
RODALCO  Offline
Member
Joined: Dec 2005
Posts: 854
Titirangi, Akld, New Zealand
If this is a 120 / 240 V supply the risk exists of overvoltages on the lighter loaded circuits when the load on the two phases is unbalanced.

Why couldn't it get fixed immidiately even with a temporary jumper to the mains POCO neutral ?


The product of rotation, excitation and flux produces electricty.

#124797 - 12/20/06 09:11 AM Re: Floating Neutral  
NORCAL  Offline
Member
Joined: Sep 2002
Posts: 873
There is a AL neutral visable in both pics. so the neutral bar is just dangling but "functioning".


#124798 - 12/20/06 07:35 PM Re: Floating Neutral  
VAElec  Offline
Member
Joined: Jul 2005
Posts: 49
Sterling, Virginia, US
Ok, this is Gould/ITE panel installed in '79. The silver tab behind is a plastic mount/isolater with the plastic threads stripped out. That is why it could not be bolted back with the existing hardware. Now that the semester is over the panel will be de-energized and everything bolted and nutted back in place.

The neutral bar is indeed floating and functioning. It was also in direct contact with the dead front so if the paint was to wear off there would a parallel bond in violation of NEC (250.30 I think).

[This message has been edited by VAElec (edited 12-21-2006).]


Pete

#124799 - 12/21/06 01:54 AM Re: Floating Neutral  
mxslick  Offline
Member
Joined: Oct 2004
Posts: 803
Atomic City, ID USA
VAelec:

Thank you for the explanation. [Linked Image] It now makes perfect sense to me. [Linked Image]

From the pics it was hard to tell that the plastic was part of the support and isolation of the bus, and thank you for understanding that my question wasn't meant to offend. [Linked Image]


Stupid should be painful.


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