A Couple NEC Questions

NightLightingFX

As a low voltage landscape lighting professional I rarely need permits so I don't know the NEC very well. I have 2 questions I would appreciate you guys helping me out on:
1) Can you have more than 3 currents carrying conductors in a raceway without derating them the 80%?
2) What is the max lenght of conduit you can run without de-rating?
Thanks
~Ned

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Ned Hastings CLVLT #0852
Night Lighting FX
www.nightlightingfx.com

480sparky

If you meet any of the exceptions to 310.15(C)(2)(a), you can.

There is no maximum length when it comes to derating. Raceway length is only limited by how long you can get conductors, and your method to pull them in.

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Speedy Petey

What type and size of conductors?
If you are working with #14, #12 or #10 then you should not have to worry about derating until you reach NINE CCC's.
Remember, the neutral of a MWBC is not counted as a CCC with regard to derating.


I am curious. What do permits have to do with knowing the codes related to your trade?

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Magnettica

480, I think what the OP was asking about as far as the maximum size length conduit before needing to derate would be 24".

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480sparky

I think you're right about the nipple length, but that would be 600 mm, not 24 inches.

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Site : the area or exact plot of ground on which anything is, has been, or is to be located.
Sight : The power or faculty of seeing; perception of objects by use of the eyes; vision.
Cite : To mention in support, proof, or confirmation; refer to as an example.

Magnettica

Oh, lol. Is that what 310.15(C)(2)(a) says? I don't have my book in front of me and I'm in the middle of filing some crap with the my new business partner the IRS.

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480sparky

No, that comes from Chapter 9, Note 4.

__________________
Site : the area or exact plot of ground on which anything is, has been, or is to be located.
Sight : The power or faculty of seeing; perception of objects by use of the eyes; vision.
Cite : To mention in support, proof, or confirmation; refer to as an example.

NightLightingFX

Thanks for the response guys I appreciate it.
~Ned

__________________
Ned Hastings CLVLT #0852
Night Lighting FX
www.nightlightingfx.com

ampman

i thought the 24" nipple rule was for conduit fill not conductor derating

Magnettica

Good question.

310.15(B)(2)(a) Exception No. 3: Derating factors shall not apply to con-
ductors in nipples having a length not exceeding 600 mm
(24 in.).

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480sparky

As well as Ch. 9, Note 4:

(4) Where conduit or tubing nipples having a maximum length not to exceed 600 mm (24 in.) are installed between boxes, cabinets, and similar enclosures, the nipples shall be permitted to be filled to 60 percent of their total cross-sectional area, and 310.15(B)(2)(a) adjustment factors need not apply to this condition.

__________________
Site : the area or exact plot of ground on which anything is, has been, or is to be located.
Sight : The power or faculty of seeing; perception of objects by use of the eyes; vision.
Cite : To mention in support, proof, or confirmation; refer to as an example.

ampman

so its settled no derating of conductors in conduit 24"(600 mm) or less and fill @ 60 % for two conductors and over

480sparky

I second that.

__________________
Site : the area or exact plot of ground on which anything is, has been, or is to be located.
Sight : The power or faculty of seeing; perception of objects by use of the eyes; vision.
Cite : To mention in support, proof, or confirmation; refer to as an example.

ampman

they are a silent partner unless dont pay