Announcement

Announcement Module
Collapse
No announcement yet.

Replacing a sub feed/panelboard

Page Title Module
Move Remove Collapse
X
Conversation Detail Module
Collapse
  • Filter
  • Time
  • Show
Clear All
new posts

  • Replacing a sub feed/panelboard

    I have a sub feed that needs to be replaced. It is connected to a 100 amp breaker supporting a garage and breezeway. This pannelboard used to contain electric baseboard heat which is slowly being phased out. Does anyone know if I can run Romex cable within rigid or EMT conduit to a pull box and use the breakers in the primary panelboard for the individual circuits. Probably 2-15 amp and 3-20 amp circuits, no 220 that I can think of.

    I have checked my 2005 NEC book and it is not real clear whether you can or can't!

    Thanks,
    Art

  • #2
    Re: Replacing a sub feed/panelboard

    Ok well... Quick answer is no. In conduit you use single conductors. THHN, THWN, RHW, XHHW, etc... depending on the application and insulation required for it. If you ever tried to push/pull romex in a conduit you'll know one of the reasons it's not allowed, it's very tough to pull it in and ruins the outer jacket. You are however permitted to 'sleeve' romex in conduit, but that's not whay I think you're asking for at this point. Basically a sleeve is when you just need to protect the romex for a short distance, in a non-complete raceway - for instance if you ran the romex along the basement ceiling, and wanted to come down the wall to a box, you could go from the wall box, to a piece of pipe, up to the top of the wall (bottom of the joists) and enter the romex in there, which is usually just 4' or so. That's considered sleeving. What you want to do is run romex through one end of a pipe that's in a j-box to the other end which is in a panel or another j-box, not allowed. That's a complete raceway and is not permitted. Now onto a question - why do you want to eliminate the sub panel? Why not just use it and run your new circuits into it, instead of all the way back to the main panel?

    Comment


    • #3
      Re: Replacing a sub feed/panelboard

      358.22 Number of Conductors.
      The number of conductors shall not exceed that permitted by the percentage fill specified in Table 1, Chapter 9.
      Cables shall be permitted to be installed where such use is not prohibited by the respective cable articles. The number of cables shall not exceed the allowable percentage fill specified in Table 1, Chapter 9.
      Table 1 of Chapter 9 specifies the maximum fill percentage of a conduit or tubing. Table 4 provides the usable area within the selected conduit or tubing, and Table 5 provides the required area for each conductor. Examples using these tables to calculate a conduit or tubing size are provided in the commentary following Chapter 9, Table 1, Notes to Tables, Note 6.
      If the conductors are of the same wire size, instead of performing the calculations, the tables in Annex C may be used. Annex C, with 12 sets of tables, accurately indicates the maximum number of conductors permitted in a conduit or tubing. Examples using Annex C to select a conduit or tubing size are provided in the commentary following the introduction in the annex.
      To select the proper trade size of electrical metallic tubing, the section entitled “Article 358 — Electrical Metallic Tubing (EMT)” in Table 4 of Chapter 9 should be followed. Tables C.1 and C.1(A) for electrical metallic tubing are also permissible.

      Comment


      • #4
        Re: Replacing a sub feed/panelboard

        Originally posted by Badabing View Post
        Ok well... Quick answer is no. In conduit you use single conductors. THHN, THWN, RHW, XHHW, etc... depending on the application and insulation required for it. If you ever tried to push/pull romex in a conduit you'll know one of the reasons it's not allowed, it's very tough to pull it in and ruins the outer jacket. You are however permitted to 'sleeve' romex in conduit, but that's not whay I think you're asking for at this point. Basically a sleeve is when you just need to protect the romex for a short distance, in a non-complete raceway - for instance if you ran the romex along the basement ceiling, and wanted to come down the wall to a box, you could go from the wall box, to a piece of pipe, up to the top of the wall (bottom of the joists) and enter the romex in there, which is usually just 4' or so. That's considered sleeving. What you want to do is run romex through one end of a pipe that's in a j-box to the other end which is in a panel or another j-box, not allowed. That's a complete raceway and is not permitted. Now onto a question - why do you want to eliminate the sub panel? Why not just use it and run your new circuits into it, instead of all the way back to the main panel?
        This brings an interesting question to mind.... Can you run MC cable through conduit by code?

        Comment


        • #5
          Re: Replacing a sub feed/panelboard

          Ok... Let's see how easy i can make this. In pipe you have 'fill' issues, where there's only a certain amount of space you are technically allowed to use. For instance 1 conductor (which say a 14/2 Romex would be considered to be) would use up .1018in of space, a piece of 1/2" EMT conduit has (at 53% fill for 1 conductor) .161in available to fill up. While you COULD pull a 14/2 in, or even a 12/2romex in a straight run, if that run has bends in it, good luck. The amount of friction on that bend will either stop you from pulling the romex through or burn up the insulation on the romex itself. I don't have specs for MC cable's outside diameter, but you get the jist of it. For more information on this, there's a good Forum (Mike Holt) that has a thread exactly on this: http://forums.mikeholt.com/showthrea...ght=romex+pipe
          Hope this helps!

          Comment

          Working...
          X