ct cabinets

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walterbboyd

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I have a situation that has arose on the use of home made ct cans,
We are a controls contractor and have two EC state license's, one of our tech was installing a new energy meter inside the panel in question. When he was complete he reinstalled the cover and a tek screw penetrated the wire and resulted in a direct short. i have attached in his words what happened.
"The following incident took place on Jan. 21, 2010 @ Medical Technology Buildings, chiller plant @ 12:00 PM. After finishing the installation of a Veris Energy meter, I was putting the cover back on the pull box attached to the switch gear. While screwing one of the tek screwing back into the enclosure, the screw penetrated the insulation of one of the A phase conductors. This resulted in a direct short to ground causing damage to the conductor and the edge of the enclosure. This accident did not cause injury to anyone, only the above mentioned equipment. I directly went to Gordy, the foremen for Electric co, to inform him of what just happened. We looked @ the enclosure and got Brad the G.C. to see how to proceed. Brad, from gc, instructed Gordy to replace the wire. This will result in a FPL shut down as these conductors go directly to the transformer. If any other info. is required please call."
My question here is it required that the conductors be in a UL raceway or is that up to the engineer to accept?
Also can the use of none UL equipment be used with state money involved?
 
walterbboyd said:
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My question here is it required that the conductors be in a UL raceway or is that up to the engineer to accept?
Also can the use of none UL equipment be used with state money involved?
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Most conduit types used in that situation are required to be listed.

Equipment is not required to be listed per se, but the following applies:
230.66 Marking. Service equipment rated at 600 volts or
less shall be marked to identify it as being suitable for use
as service equipment. Individual meter socket enclosures
shall not be considered service equipment.
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CT cabinets are covered in Article 312 and there is nothing in that article that requires the can to be a listed product. Also, depending on the location of the service point, the CT cabinet may be outside the scope of the NEC.
 
don_resqcapt19 said:
CT cabinets are covered in Article 312 and there is nothing in that article that requires the can to be a listed product. Also, depending on the location of the service point, the CT cabinet may be outside the scope of the NEC.
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I agee with both statements but feel that, based on 110.2, if the enclosure is not under POCO's jurisdiction, the AHJ can require the can to be NRTL listed.
 
augie47 said:
I agee with both statements but feel that, based on 110.2, if the enclosure is not under POCO's jurisdiction, the AHJ can require the can to be NRTL listed.
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That, in part, is why I posted 230.66. Have you ever seen an unlisted can "...marked to identify it as being suitable for use as service equipment"?
 
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Smart $ said:
That, in part, is why I posted 230.66. Have you ever seen an unlisted can "...marked to identify it as being suitable for use as service equipment"?
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If it is on the line side of the service point...the case for most all CT cans in my area...230.66 does not apply.
 
don_resqcapt19 said:
If it is on the line side of the service point...the case for most all CT cans in my area...230.66 does not apply.
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So noted.

But for the record I did make any statement to the contrary. I was replying to Gus' post regarding the can being under the NEC.
 
Smart $ said:
So noted.

But for the record I did make any statement to the contrary. I was replying to Gus' post regarding the can being under the NEC.
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No you didn't make a comment to the contrary.

It is my opinion that the CTs and CT cabinet are not "service equipment" and are not covered by the rule you cited. Even the last sentence of 230.66 is not needed as the meter is not service equipment per the Article 100 definition.
Service Equipment. The necessary equipment, usually consisting of a circuit breaker(s) or switch(es) and fuse(s) and their accessories, connected to the load end of service conductors to a building or other structure, or an otherwise designated area, and intended to constitute the main control and cutoff of the supply.
Click to expand...
 
walterbboyd said:
I have a situation that has arose on the use of home made ct cans,
We are a controls contractor and have two EC state license's, one of our tech was installing a new energy meter inside the panel in question. When he was complete he reinstalled the cover and a tek screw penetrated the wire and resulted in a direct short. .... After finishing the installation of a Veris Energy meter, I was putting the cover back on the pull box attached to the switch gear. While screwing one of the tek screwing back into the enclosure, the screw penetrated the insulation of one of the A phase conductors. This resulted in a direct short to ground causing damage to the conductor and the edge of the enclosure. ...
Click to expand...

The listing issue being addressed is almost like a red herring....

1.) Is using a tek screw proper for a cover? Removing a tek screw damages the threads it created when first installed. Re-use (and especially repeated re-use) causes the integrity of what is being fastened to suffer. I never use them for covers.

2.) Tek screws come in different lengths, but always have that carbide looking sharp cutting tip.

It seems that this could have been avoided by using the proper length machine threaded screw, and by looking to ensure that the conductor was not pressed tight to the threaded ear on the pull box.
 
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don_resqcapt19 said:
No you didn't make a comment to the contrary.

It is my opinion that the CTs and CT cabinet are not "service equipment" and are not covered by the rule you cited. Even the last sentence of 230.66 is not needed as the meter is not service equipment per the Article 100 definition.
Click to expand...
Ahh... I relinquish my point to your exemplary insight on the matter :D
 
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