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NEC Article 310.6 and application with primary transfomer cabeling

NEC Article 310.6 and application with primary transfomer cabeling

NEC Article 310.6 and application with primary transfomer cabeling

(OP)
I cannot find any reference in the NEC that excludes the connection between a close coupled disconnect switch and a transfomer with primary voltage larger than 2000V.  I cannot recall seeing any field installations that have shielded cable connections between the disconnect and the transformer, but I was wondering if this was spelled out in the code anywhere?  

RE: NEC Article 310.6 and application with primary transfomer cabeling

If the switch and transformer are both part of a listed assembly, the code requirement would not apply to the internal wiring.

RE: NEC Article 310.6 and application with primary transfomer cabeling

(OP)
Does this refer to section 310.1 when it states that these requirements of section 310 do not apply to conductors that form and integral part of equipment?

RE: NEC Article 310.6 and application with primary transfomer cabeling

Beware that the NEC primary focus is not in voltage above 2000 V.
Regardless the application, insulated conductors are typically manufactured as follow:

NON-SHIELDED:
•    2000 V for insulated single non-metallic covered cables in UG installation
•    5000 V for OH installation with separated single conductor in air.
•    5000 V for UG or OH installations with assembled conductors with a common overall jacket.
 
SHIELDED: Above 5000 V.

RE: NEC Article 310.6 and application with primary transfomer cabeling

There is a lot of unshielded conductor used within 15kV class switchgear.  Yes, 310.1 would apply as does the second paragraph of 90.7.

RE: NEC Article 310.6 and application with primary transfomer cabeling

In switchgear I believe the 15kV cable is actual space out to allow for a "bare bus" type rating through free air.

There are no manfactures of unsheilded cable as far as I know.

RE: NEC Article 310.6 and application with primary transfomer cabeling

Switchgear manufacturers sometimes use 'covered' wire, which has a rubber jacket intended only to prevent faults in the event of accidental contact.

http://okonite.com/Product_Catalog/section6/sheet4.html

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