Exterior 30a power inlet

Discussion in 'Electrical Forum discussion & Blog' started by homer777, Dec 12, 2009.

  1. homer777

    homer777 New Member

    Messages:
    13
    Location:
    nh
    Hello,

    Basic question, but I dont know the correct answer.

    I am putting in a transfer switch. I am using 3/4" sch40 conduit from the exterior power inlet to the transfer switch....and pulling in 4 #10 stranded.

    My question is how to attach (what fittings, etc) the sch 40 to the exterior power inlet.

    The sch40 will go down between the garage doors and the power inlet is on the exterior siding between the garage doors. The wall is approx 6" ( drywall, stud, plywood sheething and siding).

    I was told to use a liquid tight fitting up against the box...??

    What else?

    Thanks,

    Homer
  2. jar546

    jar546 In the Trades

    Messages:
    432
    Location:
    USA
    The exterior "power inlet" as you describe it should be in a weatherproof box and the conduit should connect directly to it.
  3. homer777

    homer777 New Member

    Messages:
    13
    Location:
    nh
    Yes, it is an official 30a exterior power inlet by GenTran......

    I have been looking online and have comeup with this....

    Inlet box -> LiquidTight 3/4 connector -> 3/4 LT NM conduit (just enough to get me in the 6" wall and up about 6" and then transition to sch 40 with a coupling....

    Does this sound correct?

    Thanks in advance.

    Homer
  4. jar546

    jar546 In the Trades

    Messages:
    432
    Location:
    USA
    Is there a knock out on the box or do you have to make your own?
    All you need is a male fitting with a locknut inside the box.

    Is this the power inlet box that has the outlet on the bottom?
  5. homer777

    homer777 New Member

    Messages:
    13
    Location:
    nh
    Yes, it has a couple of knock outs and the outlet is on the bottom.
  6. jar546

    jar546 In the Trades

    Messages:
    432
    Location:
    USA
    AS long as you don't exceed 36- degrees between pull points, you should be fine.
  7. homer777

    homer777 New Member

    Messages:
    13
    Location:
    nh
    Thanks...

    Actually have 450 degrees of bends.....five 90's to be exact...(90 to go up the wall between the garage doors, 90 at the ceiling to go down the center of the garage ,a 90 2/3 the way down the center of the garage to turn it towards the panel, 90 at the ceiling to turn it down the wall and a 90 to turn it into the panel.

    I was thinking of putting two pull points.....

    Thanks for all your help.
  8. Billy_Bob

    Billy_Bob In the Trades

    Messages:
    422
    Good grief!

    Each bend in the conduit makes wire pulling a LOT harder. But you will see...
  9. homer777

    homer777 New Member

    Messages:
    13
    Location:
    nh
    Thats what I heard....

    ...any other ideas.....

    Thanks again
  10. jar546

    jar546 In the Trades

    Messages:
    432
    Location:
    USA
    You simply need to add another weatherproof pull point such as an LB that is accessible.
  11. homer777

    homer777 New Member

    Messages:
    13
    Location:
    nh
    ..i was going to put in two access points....

    thanks
  12. Billy_Bob

    Billy_Bob In the Trades

    Messages:
    422
  13. jetlag

    jetlag New Member

    Messages:
    84
    Location:
    Ga.
    gen box

    The code only allows 4 , 90 deg bends before a junction is required, so i would go 3 then a junction and 2 more. The weather proof box does not require liquid tight . thats why the holes are in the bottom and there are tiny drain holes in the corner . I would come out of the bottom with a lock nut and male adapter then short pipe and an LB then thru wall and put silicon where you penetrate the wall . That will get you inside and around the first 90 . Its not the professional way but it helps to slide the pipe and fittings over the wire and glue them as you go instead of installing all the conduit and trying to pull all at once , It takes a lot of experience to determine if a pull is going to be a hard one , That way you dont have to worry. If you are going in attic or places not exposed you can change over 10/4 nm at a junction , thats a lot easier than conduit.
    Last edited: Dec 13, 2009
  14. frenchie

    frenchie Jack of all trades

    That's not just unprofessional, it's illegal.
  15. jetlag

    jetlag New Member

    Messages:
    84
    Location:
    Ga.
    not illegal

    It is allowed by the exception to nec 300.18 for the short run he has. Especially for pvc that wont damage wire when you carefully slide it over.
  16. frenchie

    frenchie Jack of all trades

    Yeah, um... I saw that thread you started at Holt's.

    I think you've completely misunderstood the exception. A reference to 300.15 (C), 334.15 (B), and so on, would make it less confusing, I suppose... or you can just read what's written, without trying to "read in" what isn't there in the first place:

    It's not saying anything about the sequence. Nothing about assembly before, or after, wire-pulling.

    All it's saying, is that when you're using a short run of conduit for physical protection, it doesn't have to be a complete assembly. That if the only reason you're running conduit is for physical protection, you only have to run conduit where it needs protection, not all the way back to both boxes.

    The exception is there, because otherwise 300.18 would contradict 300.15 (C), 334.15 (B), and so on.

    [​IMG]

    (taken from: http://www.co.henrico.va.us/dyn/med_document/00000000/0000000/000000/00000/0000/300/318/NEC.pdf.)




    As for your weird little notion aboout "especially with PVC" (here and at Holt's)... ever wonder what PVC cement might do to the wire insulation?





    PS - I've cross-posted this response to Mike Holt's, but it'll have to wait for mod approval to show up. How come you're "DIY junior" over here, btw, if IRL you're an electrical contractor?
    Last edited: Dec 14, 2009
  17. jetlag

    jetlag New Member

    Messages:
    84
    Location:
    Ga.
    300.18

    When I said it is not the professional way to slide conduit over conductors I should have said it is also against nec 300.18 . . I remember when that wasnt in the code. Lots of things happened. I had a man get pulled off a ladder breaking his leg . the conductors got whipped around on the floor and caught in a Lathe running in a machine shop. wound around a shaft pulling him and a section of 2" ridgid conduit off the ladder and pulled about 40 ft of wire out before could turn it off. I would never have done it that way on a new install . We were trying to replace a broken conduit with out pulling the whole 100 ft of conductors out. Some idiot used the conduit to support a chain hoist and broke off the threads.. . If you want to be naughty and slide the conduit over thats up to you. Be sure to turn off all machinery
    Last edited: Dec 15, 2009
  18. frenchie

    frenchie Jack of all trades

    Holy crap. I always though it was just about accidentally pinching the wire.
  19. jetlag

    jetlag New Member

    Messages:
    84
    Location:
    Ga.
    guess you can have a little pinch or major one. Another time I was trying to slide a piece of 3/4 emt over some wires It was going okay untill i got zapped hard when a bare end touched the conduit. Found out was more than one set of condutors from a different breaker.
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