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 Post subject: Cable sizes
PostPosted: Mon Apr 25, 2011 11:22 am 

Joined: Thu Apr 21, 2011 1:58 pm
Posts: 3
Hi,
This is my second thread to this forum.
My question concerns the field wiring sizes vs. the equipment wiring sizes. As an example, in our data center, we have 500 kcmil cable feeding our PDU's, which terminates to the line side of the main breaker. The factory wiring comes off the load side of the breaker as two 1/0 awg to the primary side of the transformer. According to the Liebert PDU manual they are alowed to down size because the cabinet is considered open air and they are allowed to use table 310.17. Does the SKM program take this into account or should the 500 kcmil size be used all the way to the primary side of the transformer?

Thanks!


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PostPosted: Tue Apr 26, 2011 4:37 am 
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Location: Rutland, VT
I don't know about SKM, but in EasyPower when entering the conductor data, you can change the default ampacity rating of the conductor. Therefore special cases can be considered.

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PostPosted: Tue Apr 26, 2011 8:15 am 
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Joined: Mon Nov 23, 2009 6:37 am
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Location: Tampa, FL
awg wrote:
Hi,
This is my second thread to this forum.
My question concerns the field wiring sizes vs. the equipment wiring sizes. As an example, in our data center, we have 500 kcmil cable feeding our PDU's, which terminates to the line side of the main breaker. The factory wiring comes off the load side of the breaker as two 1/0 awg to the primary side of the transformer. According to the Liebert PDU manual they are alowed to down size because the cabinet is considered open air and they are allowed to use table 310.17. Does the SKM program take this into account or should the 500 kcmil size be used all the way to the primary side of the transformer?

Thanks!


On SKM you should be able to add a node at the junction of the two different cables and therefore consider the circuit as it is actually run rather than changing values of installed cables.


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PostPosted: Tue Apr 26, 2011 10:08 am 
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Location: Spartanburg, South Carolina
The short section of 2-1/0 AWG will have little effect on the short circuit current and can be ignored for purposes of arc flash analysis.


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