NEC Chap 9 Table 9

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MyCleveland

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Do wire manufacturers produce similar tables for first 8 columns for different insulation types ?

What effect if six, nine, etc, conductors of same or different sizes ?
How to calculate ?
 
What are the different insulation types you are looking for? If the insulation isn't listed in the NEC then it probably isn't compliant.


If you have more than 3 current carrying conductor's ion a raceway you have to de-rate per table 310.15(B)(3)(a)

You calculate based on Chapter 9, Tables 4 and 5 for mixed sizes. Where the wires are all the same size you can use Annex C
 
Dennis
Thanks for responding....

Chap 9-Table 9, notes state table is good for "RHH" wires.
These values are representative of all 600V wiring insulation types ? or are there tables for each type, THHN, XHHW, etc. ?

I understand derating issue, but was wondering if tables exist for effect on impedance values when adding additional wires of same or different sizes ?

Tables 4, 5 and Annex C do not address impedance issue.
 
MyCleveland said:
Dennis
Thanks for responding....

Chap 9-Table 9, notes state table is good for "RHH" wires.
These values are representative of all 600V wiring insulation types ? or are there tables for each type, THHN, XHHW, etc. ?

I understand derating issue, but was wondering if tables exist for effect on impedance values when adding additional wires of same or different sizes ?

Tables 4, 5 and Annex C do not address impedance issue.
Click to expand...
In general adding more wires or limiting cooling has no effect whatsoever on impedance.


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MyCleveland said:
Thank you GoldDigger

Going through some papers on a wire manufacturer web site seemed to imply this was an issue.
Click to expand...
Running an isophase arrangement where all of the set conductors for one phase run in a separate duct can very slightly increase the inductance over having all of the conductors of a circuit being in the same duct, FWIW.

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