Derating 34 currrent carrying conductors into a metallic auxiliary gutter....

[CelsoSr]

How do I apply adjustment factors of 310.15(B)(2)(a). Taking in account the four conductors over 30 (80%), or all of them (40%) and apllying to the 34 ccc?

 

[jumper]

All the current carrying conductors.

 

[raider1]

Welcome to the forum.

You would need to take all of them into account not just the 4 over 30 that you have.

So for 34 CCC's you would need to adjust the ampacity by 40%.

Chris

 

[iwire]

Reroute at least four of the conductors.

 

[jumper]

Reroute at least four of the conductors.

I like it. :grin:

 

[raider1]

Reroute at least four of the conductors.

I like it. :grin:

I like it as well.:grin:

Chris

 

[qcroanoke]

Reroute at least four of the conductors.

Good idea.
We use a divider in the wireway when de-rate becomes a factor.

 

[Dennis Alwon]

Good idea.
We use a divider in the wireway when de-rate becomes a factor.

Where is there an allowance for that. I am assuming you mean the divider changes the derating.

 

[iwire]

Where is there an allowance for that. I am assuming you mean the divider changes the derating.

I have used trough ends as dividers and do not believe I need an allowance for it.

376.22 Number of Conductors and Ampacity. The number
of conductors and their ampacity shall comply with
376.22(A) and (B).


(B) Adjustment Factors. The adjustment factors in
310.15(B)(2)(a) shall be applied only where the number of
current-carrying conductors, including neutral conductors
classified as current-carrying under the provisions of
310.15(B)(4), exceeds 30. Conductors for signaling circuits
or controller conductors between a motor and its starter and
used only for starting duty shall not be considered as
current-carrying conductors.

 

[Dennis Alwon]

I still don't see where the divider allows you to have more than 30 conductors without derating. I think it makes sense but I don't see the wording.

 

[iwire]

I still don't see where the divider allows you to have more than 30 conductors without derating. I think it makes sense but I don't see the wording.

"Only where" if you have a wireway with 40 conductors and you place a divider in the right spot you would not have any 'where' with more than 30 conductors. I see no ambiguity or gray area.

 

[jumper]

"Only where" if you have a wireway with 40 conductors and you place a divider in the right spot you would not have any 'where' with more than 30 conductors. I see no ambiguity or gray area.

I am having a hard time seeing how this incomplete raceway divider thing gets you out of derating.

The "only where" part seems to apply to the more than 30 ccc's that are installed in a section. Only the wires that pass through that particular section.

An incomplete divider does not seem to make 2 sections of raceway out of one.

 

[CelsoSr]

Thanks...

Thanks...

Thanks to all of you for your answers. Very interesting and clever...but looks odd for me to get 40% for 4 more conductors and 100% for 30!

 

[qcroanoke]

Thanks to all of you for your answers. Very interesting and clever...but looks odd for me to get 40% for 4 more conductors and 100% for 30!

I know, but that is where the CMP drew the line in the sand.

 

[iwire]

Thanks to all of you for your answers. Very interesting and clever...but looks odd for me to get 40% for 4 more conductors and 100% for 30!

Look at it the other way ......... they gave us a major break from the 'normal' derating rules.

 

[iwire]

I am having a hard time seeing how this incomplete raceway divider thing gets you out of derating.

An incomplete divider does not seem to make 2 sections of raceway out of one.

Incomplete?

Who said it was incomplete?

If I have a 12" x 12" wireway and install a 12" x 12" blank end fitting in the middle it is about as a complete a divider as you can have.

 

[jumper]

Incomplete?

Who said it was incomplete?

If I have a 12" x 12" wireway and install a 12" x 12" blank end fitting in the middle it is about as a complete a divider as you can have.

Okay. My bad. I was misreading what you said.
I had a brain fart and was envisioning something else entirely.

 

[LarryFine]

Okay. My bad. I was misreading what you said.
I had a brain fart and was envisioning something else entirely.

Like making the 12x12 into two 12x6's?

 

[jumper]

Like making the 12x12 into two 12x6's?

Guilty as charged your honor.:grin:

 

[qcroanoke]

Incomplete?

Who said it was incomplete?

If I have a 12" x 12" wireway and install a 12" x 12" blank end fitting in the middle it is about as a complete a divider as you can have.

Would you say that using this part for the length of the wireway would make it legal to use 30 CCC's on the top and 30 CCC's on the bottom without derating?
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