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SkeetersMD

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How many current carrying conductors can be installed in a 3/4" emt, before derrating must occur? ,120/208Y 3/0 No. 12 AWG 20 amp circuits.
 
For Current Carrying conductors no matter what size the wire or conduit you must derate after 4 wires according to table 310.(15)(B)(2)(a)
 
SkeetersMD said:
How many current carrying conductors can be installed in a 3/4" emt, before derrating must occur? ,120/208Y 3/0 No. 12 AWG 20 amp circuits.
Click to expand...

You will probably get around to this additional concern,
but as a note:
"Jamming" is a problem covered by Chapter 9, Table 1.

quote:
FPN No. 1: Table 1 is based on common conditions of
proper cabling and alignment of conductors where the
length of the pull and the number of bends are within reasonable
limits. It should be recognized that, for certain conditions,
a larger size conduit or a lesser conduit fill should
be considered.
FPN No. 2: When pulling three conductors or cables into a
raceway, if the ratio of the raceway (inside diameter) to the
conductor or cable (outside diameter) is between 2.8 and
3.2, jamming can occur. While jamming can occur when
pulling four or more conductors or cables into a raceway,
the probability is very low
:quote
 
iwire said:
I agree, if you install 4 current carrying 14 AWGs in a 6" conduit the NEC still requires derating.
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iWire,
Agreed.
Is this because they fall together as a cluster of cables
on the bottom of the large conduit ?
This would cut into the ambient radiation of heat. :)
 
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