joe tedesco
Senior Member
- Location
- Boston, Massachusetts
The death of a very loose grounded conductor!
Last Rights Given for A Grounded Conductor!!
- Thread starter joe tedesco
- Start date
- Status
The death of a very loose grounded conductor!
jxofaltrds
Inspector Mike®
- Location
- Mike P. Columbus Ohio
- Occupation
- ESI, PI, RBO
Re: Last Rights Given for A Grounded Conductor!!
Is this the reason for a grounded conductor and an equipment grounding conductor not to be under the same lug????
Mike P.
Is this the reason for a grounded conductor and an equipment grounding conductor not to be under the same lug????
Mike P.
brian john
Senior Member
- Location
- Leesburg, VA
Re: Last Rights Given for A Grounded Conductor!!
For any two cudoctors to be under that type of set screw termination block. The second wire gets pushed aside and makes poor contact. A common discrepancy noted in out IR/thermographic surveys.
For any two cudoctors to be under that type of set screw termination block. The second wire gets pushed aside and makes poor contact. A common discrepancy noted in out IR/thermographic surveys.
william runkle
Senior Member
- Location
- Michigan
Re: Last Rights Given for A Grounded Conductor!!
What is on the top side of terminal block? It looks like aluminum stranded wire with some strands going in the first screw along with some copper wires. If it is dissimilar wires touching each other could be next grounded conductor death. I am not sure it is but it looks like it.
What is on the top side of terminal block? It looks like aluminum stranded wire with some strands going in the first screw along with some copper wires. If it is dissimilar wires touching each other could be next grounded conductor death. I am not sure it is but it looks like it.
Re: Last Rights Given for A Grounded Conductor!!
It looks to me if the EGC (green) was placed under the same screw and the neutral. Another problem when this is done is that the screw favors one of the conductors, tightening down on it, than the second conductor which may be semi tight or loose. The termination should be listed for the number of conductors, the wire size range, and cu or al or both. Even the use of stranded vs solid wire can pose a termination problem.
It looks to me if the EGC (green) was placed under the same screw and the neutral. Another problem when this is done is that the screw favors one of the conductors, tightening down on it, than the second conductor which may be semi tight or loose. The termination should be listed for the number of conductors, the wire size range, and cu or al or both. Even the use of stranded vs solid wire can pose a termination problem.
stamcon
Senior Member
- Location
- South San Francisco CA
Re: Last Rights Given for A Grounded Conductor!!
What's up with the threaded hole in the bracket at the top of the bar? Was the stranded aluminum(?) suppose to be connected there? Was there no line neutral connected to the bar and the ground wire cooked because of that condition?
What's up with the threaded hole in the bracket at the top of the bar? Was the stranded aluminum(?) suppose to be connected there? Was there no line neutral connected to the bar and the ground wire cooked because of that condition?
G
Guest
Guest
Re: Last Rights Given for A Grounded Conductor!!
It looks like the main ground or neutral (AL) slid out of the lug and started arcing on the grounding bar. The screw and keeper in the lug are missing (the right side looks gone). The ends of the AL are burned (melted). What a mess!
It looks like the main ground or neutral (AL) slid out of the lug and started arcing on the grounding bar. The screw and keeper in the lug are missing (the right side looks gone). The ends of the AL are burned (melted). What a mess!
B
bthielen
Guest
Re: Last Rights Given for A Grounded Conductor!!
About the only way I can imagine a good connection in this circumstance is if the two conductors were twisted together before terminating. Perhaps the NEC should address multiple conductors in terminals? Any other thoughts?
Bob
About the only way I can imagine a good connection in this circumstance is if the two conductors were twisted together before terminating. Perhaps the NEC should address multiple conductors in terminals? Any other thoughts?
Bob
Re: Last Rights Given for A Grounded Conductor!!
Sometimes you can't see the forest through the trees I guess. It was easy to zero in on the failed neutral conductor when just above it was a neutral conductor that appears to be loose and not terminated as awwt so apply pointed out.
Could it be that the loss of that neutral conductor cause the branch neutral conductor to fail.
If one were to loose a neutral we are aware of the catastrophic results that could have on the connected loads. If we can determine that that neutral at the top of the bar was not terminated and, therefore, not connected at all could it be that the obviously failed branch circuit neutral conductor happened to be grounded downstream at some other point which provided a path for all of the neutral current from the other branch circuits to use as a return path, thus overloading that neutral.
Sometimes you can't see the forest through the trees I guess. It was easy to zero in on the failed neutral conductor when just above it was a neutral conductor that appears to be loose and not terminated as awwt so apply pointed out.
Could it be that the loss of that neutral conductor cause the branch neutral conductor to fail.
If one were to loose a neutral we are aware of the catastrophic results that could have on the connected loads. If we can determine that that neutral at the top of the bar was not terminated and, therefore, not connected at all could it be that the obviously failed branch circuit neutral conductor happened to be grounded downstream at some other point which provided a path for all of the neutral current from the other branch circuits to use as a return path, thus overloading that neutral.
G
Guest
Guest
Re: Last Rights Given for A Grounded Conductor!!
../Wayne C.
[ September 18, 2003, 02:34 PM: Message edited by: awwt ]
I was trained to terminate no more than one neutral per screw and no more than two bares or greens per screw (if you needed to double up). Of course one wire per screw would be preferred-- especially if they are not the same AWG. It appears the first screw has a white and a bare. Assuming the white is neutral that wouldn't have passed my SOP.
../Wayne C.
[ September 18, 2003, 02:34 PM: Message edited by: awwt ]
ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: Last Rights Given for A Grounded Conductor!!
Take a look at article 408.21
G
Guest
Guest
Re: Last Rights Given for A Grounded Conductor!!
Glad to hear the NEC caught up with what I was trained to do almost 30 years ago. I left out the part about the panel specs usually dictating this anyway.
http://www.yaunco.com/ycreport/nov02noframe/neccode.html
../Wayne C.
[ September 18, 2003, 06:50 PM: Message edited by: awwt ]
Glad to hear the NEC caught up with what I was trained to do almost 30 years ago. I left out the part about the panel specs usually dictating this anyway.
I snipped that from this link:
http://www.yaunco.com/ycreport/nov02noframe/neccode.html
../Wayne C.
[ September 18, 2003, 06:50 PM: Message edited by: awwt ]
cselectric
Senior Member
- Location
- Wisconsin
Re: Last Rights Given for A Grounded Conductor!!
I really must start taking pictures of the installs I see on service detail. These are great learning aids, if only because they make us all think.
The last time I saw anything like that was a grounding conductor. Retail environment, the circuit was ru about 300-350 feet to the front of the store. This circuit fed a ceiling recept. that hadn't been used since occupancy. The owner decided to use it to plug in a Christmas display and found it not working, so I got the call.
Anyway, I started searching back through the circuit to find the problem. In the junction box above ceiling, immediately above the recept. I found the wires had been recolored using magic marker (same thing in the panel.) I guess the color didn't adhere well during the pull, because the grounded conductor was spliced to the hot circuit conductor in that box. So, the hot leaves the breaker, goes out 300 ft. splices to the grounded conductor and goes 300 ft. back to the panel. At the panel, the grounded conductor was loose at the terminal and had burned itself up due to arcing. I guess 120V across 600 ft. of #12 THHN creates a situation where the breaker was unable to clear the short. So, the circuit sat there burning itself up at the neutral bus without the CB dumping. No one noticed because the circuit was never used.
I really must start taking pictures of the installs I see on service detail. These are great learning aids, if only because they make us all think.
The last time I saw anything like that was a grounding conductor. Retail environment, the circuit was ru about 300-350 feet to the front of the store. This circuit fed a ceiling recept. that hadn't been used since occupancy. The owner decided to use it to plug in a Christmas display and found it not working, so I got the call.
Anyway, I started searching back through the circuit to find the problem. In the junction box above ceiling, immediately above the recept. I found the wires had been recolored using magic marker (same thing in the panel.) I guess the color didn't adhere well during the pull, because the grounded conductor was spliced to the hot circuit conductor in that box. So, the hot leaves the breaker, goes out 300 ft. splices to the grounded conductor and goes 300 ft. back to the panel. At the panel, the grounded conductor was loose at the terminal and had burned itself up due to arcing. I guess 120V across 600 ft. of #12 THHN creates a situation where the breaker was unable to clear the short. So, the circuit sat there burning itself up at the neutral bus without the CB dumping. No one noticed because the circuit was never used.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: Last Rights Given for A Grounded Conductor!!
Me too as I would like to find a camera that would combine the inferred imaging and regular photography in one camera. this would be a very useful camera to have. with about five mega pix and be able to record to a DAT tape this would allow for many photo's of high resolution
Me too as I would like to find a camera that would combine the inferred imaging and regular photography in one camera. this would be a very useful camera to have. with about five mega pix and be able to record to a DAT tape this would allow for many photo's of high resolution
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