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#212710 - 02/07/14 02:14 PM Switchgear problems  
Wmackay  Offline
New Member
Joined: Feb 2014
Posts: 8

[Linked Image]

insulation dripping on floor

any one know what this is?
what is happening here?


Last edited by Wmackay; 02/07/14 02:17 PM.

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#212711 - 02/07/14 03:24 PM Re: Switchgear problems [Re: Wmackay]  
Tesla  Offline
Joined: Jun 2004
Posts: 1,273
Sacramento, CA
By its appearance: that's one heck of a current transformer on the neutral bus.

It's toasty because you must have plenty of neutral current.

The CT looks like it has fallen down onto the bussing, I would never imagine having a CT so mounted.

Its size and the number of turns is quite odd, custom in every way. It looks like an improvisation -- in the field.

Where'd you get the snap?


#212719 - 02/07/14 06:52 PM Re: Switchgear problems [Re: Wmackay]  
JBD  Offline
Joined: Jul 2001
Posts: 599
Looks like this might be a zero sequence ground fault CT.

Definitely is overheating and melting the insulation.

Absolutely should not be 'resting on' the busbars.

#212720 - 02/07/14 08:07 PM Re: Switchgear problems [Re: Wmackay]  
HotLine1  Offline

Joined: Apr 2002
Posts: 6,874
Brick, NJ USA
Possibility that this is the end result of a sloppy job of someone using red liquid tape?? Or insulating varnish??

IMHO, looks like someone made this to possibly monitor the current in the neutral buss, and it appears that there is some means of support via the black material on the neutral buss, left of the five bolt connection.

Did you use an IR to check IF the temp was high? If this was any 'mfg' CT device, it would have a compliant mounting.

Look close at what appears to be some 'windings'.

Not being to cruel, but....Rube Goldberg??

What are the black marks that look like burns on the phase buss where branch CBs are fed??


#212725 - 02/07/14 09:10 PM Re: Switchgear problems [Re: Wmackay]  
Tesla  Offline
Joined: Jun 2004
Posts: 1,273
Sacramento, CA
Taking a second look...

The CT ought never be mounted directly so close to a right-angle bend in the neutral bussing.

For the CT is going to be reading flux across ninety-degrees, too.

You'd have to have a conducting shield so as to magnetically isolate the CT.

The CT also looks like it's a total hack job. CTs are not supposed to be so over-sized.

It appears that the bizarro size was crafted so as to permit the screw-ball mounting seen in the pic.

With just the one view point, I'm restricted.

More commentary is in order from the OP.

Bus voltage, Amps, load?

Who crafted the CT?


The mount to the right -- at the neutral bus -- is way strange.

I'd shut the system down and remove this gadget immediately.

Call in a real EE to design a NEMA factory correct solution.

This type of gadget is exactly why the Code shuns non-UL mock-ups. Back in the day, everyone and his brother thought they knew what they were doing. The result was fire and death all over the nation... starting with the World's Fair in Chicago.

Last edited by Tesla; 02/07/14 09:11 PM.


#212726 - 02/07/14 09:26 PM Re: Switchgear problems [Re: Wmackay]  
HotLine1  Offline

Joined: Apr 2002
Posts: 6,874
Brick, NJ USA
Look at the mechanical lug, looks like two non-compliant taps; one down to the right, one to this CT.


Did you ever come upon the older E-Mon split core CTs? They had to mating steel laminate cores to go around conductors, or buss (for the brave). I saw some really bad installs over the years. The 2k amp cores were 8-10" square with a plastic snap cover and ty-wraps! The CT winding slipped onto the core....


#212727 - 02/07/14 10:59 PM Re: Switchgear problems [Re: Wmackay]  
Tesla  Offline
Joined: Jun 2004
Posts: 1,273
Sacramento, CA
Did someone bond the CT core laminations to the neutral bus?

For the picture strongly implies that the windings tap in and out at the upper right...

Making the weird tap at the mechanical lug hard to explain.

The entire affair needs elaboration by the OP.


#212728 - 02/07/14 11:15 PM Re: Switchgear problems [Re: Wmackay]  
HotLine1  Offline

Joined: Apr 2002
Posts: 6,874
Brick, NJ USA
IMHO, it looks like a laminated core, with wire (conductors) spiral wrapped, probably bare; with a 'stakon' butt crimp to the insulated conductors.


How about some more info??


#212729 - 02/08/14 04:43 PM Re: Switchgear problems [Re: Wmackay]  
geoff in UK  Offline
Joined: Dec 2002
Posts: 185
Something weird. Where is the heat supposed to be from to melt insulation?

#212730 - 02/08/14 06:13 PM Re: Switchgear problems [Re: Wmackay]  
sparkyinak  Offline
Joined: Jul 2007
Posts: 1,328
If it wrapped in just electrical tape, it don't have to get hot tot for the adhesive to run. The equipment can be in close proximity to a furnace or something. If the CT does come in contact with the bus, you will have one heck of a mess on your hands. Judging by the size of the electrical equipment, that would be rather expensive interruption. At the same time, i totally agree with the other posters. A good IR scan will speak volumes and load analylsis wouldn't hurt. Your facility has alot of money riding on its power to be using homemade equipment.

"Live Awesome!" - Kevin Carosa

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