Innerduct Maximum Fill

[NEC User]

NEC requires limititing conduit fill of multiple wires to 40% maximum within a conduit. My understanding is this is required so insulation doesn't get damaged and cause a fire. Is there a similar fill restriction for innerduct installed within a conduit (a smaller conduit installed within a larger conduit)? I haven't been able to find this restriction in NEC. I think the NEC doesn't specify a restriction because if the conduit gets damaged it won't cause an electrical fire. In this case, whatever the Contractor can fit is suitable.

Please confirm.

 

[north star]

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Wouldn't the same conduit fill restrictions apply, ...afterall
it is another conduit?

Also, ...Welcome to the Mike Holt Forum **Malteser** !

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[NEC User]

Thank you for the welcome! This site is great.
I agree the Innderduct can only be filled with wires up to 40% maximum. But is the innerduct limited to only able to fill the conduit up to 40%?

 

[north star]

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See Article 300.17, `08 NEC [ " ...in any raceway" ].

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[don_resqcapt19]

I don't think that there is any provision that actually lets you install innerduct in conduit.

 

[NEC User]

Article 300.17 is what I needed. Thankyou everyone for your responses.

 

[north star]

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C`mon on back now, ...ya hear!

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[iwire]

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Wouldn't the same conduit fill restrictions apply, ...afterall
it is another conduit?

Also, ...Welcome to the Mike Holt Forum **Malteser** !

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Typical inner duct is not a raceway.

 

[iwire]

NEC requires limititing conduit fill of multiple wires to 40% maximum within a conduit. My understanding is this is required so insulation doesn't get damaged and cause a fire. Is there a similar fill restriction for innerduct installed within a conduit (a smaller conduit installed within a larger conduit)? I haven't been able to find this restriction in NEC. I think the NEC doesn't specify a restriction because if the conduit gets damaged it won't cause an electrical fire. In this case, whatever the Contractor can fit is suitable.

Please confirm.

There are no NEC fill limits if you are talking about data lines.

 

[north star]

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"There are no NEC fill limits if you are talking about data lines."

At least one manufacturer states that the [ general ] rule is 40% fill.....Please see the link.

http://www.endot.com/faq/ul_651b_conduit/7

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