adding a sub panel

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Rich2774

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I have an old 100amp 8 ckt fused panel I want to add a sub-panel . Would it be correct to come of the two lugs at the bottom of the bus bar with #6 and feed 50amp main breaker in the sub panel which is only 4ft away or can I just come off those lugs with #3s and go into the main lugs of the sub panel, Being that the main are 100amp fuses.
 

raider1

Senior Member
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Location
Logan, Utah
What type of wiring method are you going to use?

Either one could work.

If you use the #6 you would need to follow the tap rules of 240.21(B) but that would be fairly easy to accomplish if the panel is only 4' away.

#3 THHN copper would have an ampacity of 100 amps at 75 degrees C. If you use an NM cable or a SER cable (Under the 2008 NEC) then you must calculate the ampacity in accordance with the 60 degree column.

Chris
 
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