Service panel connection.

Discussion in 'Electrical and Wiring' started by Hack, Dec 14, 2007.

  1. Dec 14, 2007 #1

    Hack

    Hack

    Hack

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    I have a question about a service panel connection...

    I need to get power to the upper floor of my home. I plan to replace the Romex running through a conduit on the outside of the wall up to the attic with individual wires. You might be able to see the conduit running up the tall wall on the right between the two drafty windowsl in the picture. There are three things going up the wall. Power (3/4" rigid conduit), gas pipe, and A/C coil drain pipe.

    The conduit goes into the house through the wall and is terminated at either end just inside the walls with a bushing. The "bare" Romex then runs along joists to the main panel downstairs, and to a junction box in the attic.

    My plan is to remove the romex from the conduit and replace it with 7 12ga. wires (three black, three white, and one ground) to increase my circuits from two to three upstairs. I will attach a piece of flex conduit to the end of the rigid and extend the conduit over to the junction box in the attic. In the basement, I would do the same...attach a piece of flex conduit to the end of the rigid just inside the wall and run it over to the back of the main panel.

    Of course, I know that I need to encase the individual wires in something through the open attic and open basement...

    So, long introduction for a "simple" question:

    Can I run flex conduit from the back of the main panel through my basement (attached to floor joists) and attach the other end to the rigid conduit, or do I have to use rigid conduit for this purpose?

    I live in CA, in case that makes a difference...

    TIA.

    135_3547.jpg
     
  2. Dec 14, 2007 #2

    kok328

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    reply rescinded ... sorry.
     
  3. Dec 15, 2007 #3

    travelover

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    Wow, that is a cool looking house.

    Re the wiring, I would suggest that you ask for advice from your local building department. They may even have the information on line.
     
  4. Dec 15, 2007 #4

    glennjanie

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    Hey Jeff:
    Beautiful home there. I would run ridgid (even if it has to be PVC) on both ends. I'm not an authority on the NEC or the CA electrical code but I know the 3/4" conduit has a maximum load (or number of wires) and I believe you are within the limit.
    I think the flex is limited in length to 6' and that is only to connect to a drop in flourescent light or something of that nature. I also know the ridgid conduit in metal is acceptable as a mechanical ground, leaving you to use a grounding pigtail in each fixture box.
    Where is Petey when we need him?
    Glenn
     
  5. Dec 18, 2007 #5

    speedy petey

    speedy petey

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    Sorry, I haven't checked in here in a while. Better late than never.

    The flex idea is fine. The 6' limit has it's limits. As long as a ground is run you can run as much flex as you want. I'd run an actual ground wire in ANY case. I've seen way too many compromised conduit systems to rely solely on that.

    I'd use a box to change over from flex to conduit. I'd not like to see a flex fitting in the middle of a conduit run.

    Also, you can run multi-wire circuits if you are familiar and comfortable with them. This will let you run less wires in the conduit.
     
  6. Dec 18, 2007 #6

    glennjanie

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    Thanks for comming in there Petey, YOU DA MAN when it comes to electrical. I've been out of it too long and am not up with the NEC.
    Merry Christmas
    Glenn
     
  7. Dec 18, 2007 #7

    Hack

    Hack

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    Thanks for the information everyone.

    I will be running a ground up to the attic rather than relying on the conduit itself...better safe than sorry.

    Petey, Couple of questions...
    Is it necessary to use a box between the rigid and flex? If so, I'll just eliminate the flex and run romex from the box to where I need it.

    I'm not sure I understand what you mean by multi wire. If I was to guess, you're saying that I could run two black, two red, two white (and a ground) for four total circuits? I thought sharing a neutral was bad???

    TIA,
    Jeff.
     
  8. Dec 19, 2007 #8

    kok328

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    You can run a total of four circuits with the same amount of wire. Four black, two white and 1 green. Just make sure that the two blacks sharing a white come from opposite phases in your breaker box. Also, match all hardware (wire, switches & outlets) to the amperage of the circuit (12ga = 20amps, 14ga = 15 amps). Due to the cost of wire, I'm seeing alot of electricians leaving out the ground wire and trusting the conduit to be the ground. You can do this also but, be sure to bridge anything non-metalic w/a ground wire (i.e.-seal tight and/or plastic jboxes).
     
  9. Dec 19, 2007 #9

    Hack

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    I'm running a dedicated ground. My plan is to run three black, three white, and one ground (all 12ga.) through the conduit up to the attic and into a large metal box to make wiring easy. From there, I'll run Romex to the circuits.

    I think I now understand shared neutrals, but I don't know that I'm comfortable enough doing this and doing it right. If I run dedicated hot/neutral pairs, I don't have any question...

    Thanks for all the input! I guess it's back up to the attic with me...

    Oh, and off to the rental place for a really big boom lift.

    I had thought about renting a 40' extension ladder, but getting their 66' boom lift is only $300 for the day, and my Emergency Room deductible is $200. I'm goin' with the boom. The top of the conduit run on the outside of the house is ~35' up :eek:
     
  10. Dec 20, 2007 #10

    kok328

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    I don't know your situation but, if it were me, I'd just run a non-metalic fish tape down the conduit and pull my wires back from there. No ladder or boom required.

    P.S. - Nice house!
     
  11. Dec 26, 2007 #11

    Parrothead

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    Actually, he has to. As of the '05 NEC, conduits are no longer acceptable as equipment grounds. You MUST run a ground wire.

    Oh, and I haven't checked in in awhile either.......
    :eek:
     
  12. Dec 29, 2007 #12

    speedy petey

    speedy petey

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    You must mean after the 2005 NEC. I can't comment as I do not have a copy of 2008 yet.
     
  13. Dec 29, 2007 #13

    glennjanie

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    Common neutral wires work in a lot of situations but our local electrical inspector wants to check the amps on the commons to be sure they are not overloaded. If your power wires are under the maximum rated load, the common is too. Then, if the common is connected to more than one power wire it can heat up pretty quickly.
    Glenn
     
  14. Dec 30, 2007 #14

    480sparky

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    From the 2005 AND 2008 NEC: (there are no changes in 2008 for this section)

    250.118. Types of Equipment Grounding Conductors. The equipment grounding conductor run with or enclosing the circuit conductors shall be one or a combination of the following:

    (1) A copper, aluminum, or copper-clad aluminum conductor.....
    (2) Rigid metal conduit.
    (3) Intermediate metal conduit.
    (4) Electrical Meallic tubing.
    (5) Listed flexible metal conduit......
    (6) Listed liquidtight flexable metal conduit....
    (7) Flexible metallic tubing......
    (8) Armor of Type AC cable......
    (9) The copper sheath of mineral-insulated, metal-sheathed cable.
    (10) Type MC cable where listed and identified for grounding.....
    (11) Cable trays....
    (12) Cablebus framework....
    (13) Other listed electrically continuous metal raceways and listed auxilliary gutters.
    (14) Surface metal raceways listed for grounding.

    (portions edited because I didn't want to type all the little details)



    So yes, you can still use the raceway as a ground.
     
  15. Dec 31, 2007 #15

    speedy petey

    speedy petey

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    Yup. Looks like what I read.

    BTW- You typed all that??? Boy, we need to get you a CD!
     
  16. Dec 31, 2007 #16

    480sparky

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    I have the '05 CD, but I typed it from the 2008 before I realized there were no changes from the '05 :mad:
     
  17. Jan 2, 2008 #17

    Hack

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    Thanks for all the input guys!

    So I ended up cutting an 18" X 18" hole in the sidewall of the house from inside the attic (just above the top of the conduit run). I put hinges and a latch on the door so it opens into the attic. Later, I'll probably put an attic fan there, or just a louvered vent. This was much easier and safer than a 40' ladder...

    Running the wire was much easier than I thought after that. After pulling the 4 wire romex out of the run, I ran a fish tape UP through the conduit and pulled the wire down the run. I was in the attic and my wife on the ground. She didn't even really have to pull. I just dropped the wires down through the run and the weight of the fish wire and tape pulled them down.

    All my electrical and plumbing is now done and inspected (we closed the office for 11 days for X-Mas so I had the time to work on the bathroom).

    I've also got drywall up and inspected as well...should be done in a month or two (Now that I'm back at work again...)
     

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