18" Min/10' Max

[A/A Fuel GTX]

Looking for the code reference pertaining to installing a conduit sleeve into a panel that contains nm-b conductors for example. I know I saw it somewhere and it states that the sleeve must be 18" min and 10' max. Can't recall if derating was required for such an installation. Any help appreciated.

 

[kwired]

312.5(C) exception is the code section. The informational note after suggests that ampacity adjustments apply, so your sleeve must be a minimum of 18" but wouldn't need ampacity adjustments if 18-24".

 

[packersparky]

Looking for the code reference pertaining to installing a conduit sleeve into a panel that contains nm-b conductors for example. I know I saw it somewhere and it states that the sleeve must be 18" min and 10' max. Can't recall if derating was required for such an installation. Any help appreciated.

You must have read that when you were in Wisconsin. It's a Wisconsin amendment in SPS 316.312(1). Ampacity adjustments may still be required.

 

[kwired]

You must have read that when you were in Wisconsin. It's a Wisconsin amendment in SPS 316.312(1). Ampacity adjustments may still be required.

What does WI have that is different from NEC? What OP mentioned is all in NEC plus additional requirements that must be met to enter a panel with this method in the section I mentioned before.

 

[packersparky]

What does WI have that is different from NEC? What OP mentioned is all in NEC plus additional requirements that must be met to enter a panel with this method in the section I mentioned before.

You are correct. Wisconsin just removes the words "surface mounted" from 312.5(C) Exception.

 

[A/A Fuel GTX]

Thanks for the replies. Yes, WI overrides some of the NEC requirements. The derating issue sort of makes this wiring method hard to utilize however. Say you run a 2" X 10' sleeve into the top of a panel vertically from attic space. If NM-B were used, you could only run 4, 12-2 / 120V /20A circuits legally, without increasing wire size. IMO, the derating requirement should be removed via an exception for cases like this but that's just me. With all the spray foam insulation going on these days, groups of NM-B wires are virtually encapsulated to the point of being invisible. I know there is a reference to how many CCC's can pass through a bored hole that is spray foamed but what about the aforementioned scenario?

 

[packersparky]

Thanks for the replies. Yes, WI overrides some of the NEC requirements. The derating issue sort of makes this wiring method hard to utilize however. Say you run a 2" X 10' sleeve into the top of a panel vertically from attic space. If NM-B were used, you could only run 4, 12-2 / 120V /20A circuits legally, without increasing wire size. IMO, the derating requirement should be removed via an exception for cases like this but that's just me. With all the spray foam insulation going on these days, groups of NM-B wires are virtually encapsulated to the point of being invisible. I know there is a reference to how many CCC's can pass through a bored hole that is spray foamed but what about the aforementioned scenario?

Wiscosin does amend the ampacity adjustments of 310.15 (B)(3)(a) and 310.15(B)(2)(a) for dwelling units. Ampacity adjustments only apply to NM cables wher they are run through holes in studs that are to be draft or fire stopped and where they are in contact with thermal without manintaining spacing.
See SPS 316.310 for the specifics.

 

[A/A Fuel GTX]

Wiscosin does amend the ampacity adjustments of 310.15 (B)(3)(a) and 310.15(B)(2)(a) for dwelling units. Ampacity adjustments only apply to NM cables wher they are run through holes in studs that are to be draft or fire stopped and where they are in contact with thermal without manintaining spacing.
See SPS 316.310 for the specifics.

So you are saying that the ampacity adjustment pertaining to the number of CCC's in a sleeve like 312.5(C) relates to is overridden by the WI amendments to the NEC? So basically the only concern is conduit fill? That makes sense to me.

 

[packersparky]

Wiscosin does amend the ampacity adjustments of 310.15 (B)(3)(a) and 310.15(B)(2)(a) for dwelling units. Ampacity adjustments only apply to NM cables wher they are run through holes in studs that are to be draft or fire stopped and where they are in contact with thermal without manintaining spacing.
See SPS 316.310 for the specifics.[/QUOTE]

So you are saying that the ampacity adjustment pertaining to the number of CCC's in a sleeve like 312.5(C) relates to is overridden by the WI amendments to the NEC? So basically the only concern is conduit fill? That makes sense to me.[/QUOTE]

For dwelling units, thats pretty much it.