Wireway 30 current carrying conductors

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elecold

Member
A wireway cant have more than 30 CCC without derating.
Question
If using a wireway for a splice point. Individual branch circuits going in then splicing and going out.
Do I count the two MC cables as four ccc or because they are the same circuit and just a splice point count it as just two CCC?
I realize the 75% splice fill.
I'm just trying to count correct current carrying conductors for defeating.
Thanks
 

augie47

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Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Interesting question.
I have always read into that Code section "cross sectional area" {even though those words don't appear in (B)} and counted wires per cross section so two spliced conductors would be two, but I can see it being looked at in a different light,
 

GoldDigger

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Location
Placerville, CA, USA
Occupation
Retired PV System Designer
Interesting question.
I have always read into that Code section "cross sectional area" {even though those words don't appear in (B)} and counted wires per cross section so two spliced conductors would be two, but I can see it being looked at in a different light,

I would look at it this way:
One THWN coming in from the right, spliced to one THWN going out the left equals one wire in every cross section you check. Especially if it is a butt splice rather then a wire nut.
Two THWNs coming in from the right and spliced somewhere inside would be two wires at some cross sections.
One THWN coming in, going to the middle, and bending back to exit the right again would also be two conductors in some cross sections even though it is the same wire.
The latter could be problematic if applied to coiled or folded extra lengths of connected wires stored in the wireway (so don't do it!?). But based on the rationale for the 30 conductor limit (mainly heating) it seems to make sense.
 

Carultch

Senior Member
Location
Massachusetts
A wireway cant have more than 30 CCC without derating.
Question
If using a wireway for a splice point. Individual branch circuits going in then splicing and going out.
Do I count the two MC cables as four ccc or because they are the same circuit and just a splice point count it as just two CCC?
I realize the 75% splice fill.
I'm just trying to count correct current carrying conductors for defeating.
Thanks


Each wire within a multiconductor cable assembly is counted, provided that it qualifies as "current-carrying". So a 4-wire + ground cable assembly is counted as 4 wires, if all 4 wires carry current. A group of 8 such cable assemblies would count as 32 current-carrying conductors.

Remember:
Neutrals may or may not count. Verify this.
Spare conductors do count, since the intention is that they will carry current tomorrow.
Conductors that cannot be energized simultaneously only count as the maximum that will be energized at once. Think travellers in a 3-way switch.
 
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