Wireway Derating

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infinity

infinity

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Is it just me or is requiring derating for the conductors in this wireway pretty silly?

Trough.jpg
 
Looks like there probably is more then 30 conductors at at least one cross sectional area.

What are the load currents though?

If 480 volts and all motors are no more then 5 HP - 14 AWG still has sufficient ampacity after adjustments. 12 AWG would be fine for no more then 10 HP motors.
 
kwired said:
Looks like there probably is more then 30 conductors at at least one cross sectional area.

What are the load currents though?

If 480 volts and all motors are no more then 5 HP - 14 AWG still has sufficient ampacity after adjustments. 12 AWG would be fine for no more then 10 HP motors.
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I see 48 conductors (8 units X 6 conductors) at the area to the left of units 1 and 5.
table 310.15(B)(3)(a) shows 35% for 41 conductors and above.
That's what I see anyway..... ;)
But it is silly to have to derate when you could run a full grown groundhog through that wireway.......
 
I'm with Rob on this-this is harmless. How is this any different than a large cross section of conductors in a panelboard? So it is a violation in the wireway but not the panelboard. Or if this was a nipple 24" or less and crammed to 60% fill it would also get a pass. An insult to one's common sense.
Next we can argue if it is being used as wireway or pull box-another crazy area of the code.
 
texie said:
I'm with Rob on this-this is harmless. How is this any different than a large cross section of conductors in a panelboard? So it is a violation in the wireway but not the panelboard. Or if this was a nipple 24" or less and crammed to 60% fill it would also get a pass. An insult to one's common sense.
Next we can argue if it is being used as wireway or pull box-another crazy area of the code.
Click to expand...

it seems to be more of a pullbox than a wireway to me.
 
petersonra said:
it seems to be more of a pullbox than a wireway to me.
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OK, many would agree based on those conduits that look like they go out to a load off some distance away. In this case it is a non issue as the conductors are smaller than #4, but what if they were #4 or larger, would you view the sizing of the wireway as compliant?
 
You guys pretty much summed up my argument, they could have used a long pull box in lieu of the wireway and then we wouldn't be having this conversation even though the two installations would be electrically identical. As Kwired alluded to in this case the ampacity adjustment didn't change anything due to the small drives and the #10 conductors.
 
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