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Discussion Starter #1
I am mounting an inlet box to the back wall near my main elec panel and transfer switch panel. It wil lonly be a foot or 2 run from the box to the xfer panel. The xfer panel is designed for 7.5KW and the inlet box has a L14-30 connector. I plan to surface mount the box outside and use a rear knockout to feed the wire through the siding.

Not sure what kind of wire is best or required or if I should (or must?) use.
 

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Master Electrician
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A conduit would work with thwn wires sized for the amperage or I believe, and someone will correct me, that because its just a sleeve you can run PVC through the wall and pull an nmwu(undergroud/wet) multi conductor in.
 

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Cruising into the sunset
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You need wire rated for the system. The L14-30R receptacle means they rated the system for 30A. That requires #10 conductors.

  1. Install a pipe nipple through the wall from the transfer switch to the panel.
  2. Caulk around the pipe.
  3. Install (4) #10 THHN (H-H-N-G)
  4. Make sure the neutral is identified as white and the ground identified as green - both ends. For identification, mark one hot with red tape. You now have B-R-W-G. It will make terminations a no-brainer.
  5. Terminate as per instructions.
 

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Discussion Starter #4
That's pretty much what I did but I used NMB 10-3 romex. Has black and red for hots, white neutral, and ground, of course. This is all inside and is concealed in the wall as it is in finished space. Hope that is OK?? Took me awhile to figure out the pipe nipple penetration. I used some silicone sealant and some elec putty,and stainless steel screws to mount the inlet box. It's sealed up pretty well.

So far the inlet box is just roughed in as I need to get a longer piece of flex conduit to connect the xfer panel to the main elec panel. The piece supplied by the mfg was too short for my physical arrangement. I have to go to a local elec suppy house tomorrow to get a longer piece of 1 1/4" flex conduit.

You need wire rated for the system. The L14-30R receptacle means they rated the system for 30A. That requires #10 conductors.

  1. Install a pipe nipple through the wall from the transfer switch to the panel.
  2. Caulk around the pipe.
  3. Install (4) #10 THHN (H-H-N-G)
  4. Make sure the neutral is identified as white and the ground identified as green - both ends. For identification, mark one hot with red tape. You now have B-R-W-G. It will make terminations a no-brainer.
  5. Terminate as per instructions.
 

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E2 Electrician
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5,655 Posts
I am mounting an inlet box to the back wall near my main elec panel and transfer switch panel. It wil lonly be a foot or 2 run from the box to the xfer panel. The xfer panel is designed for 7.5KW and the inlet box has a L14-30 connector. I plan to surface mount the box outside and use a rear knockout to feed the wire through the siding.

Not sure what kind of wire is best or required or if I should (or must?) use.
10-3 NM cable will suffice.
 
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