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Right Angle Drill inside finished wall and Horizontal receptacles?

Right Angle Drill inside finished wall and Horizontal receptacles?

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  #1  
Old 01-28-14, 06:44 AM
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Right Angle Drill inside finished wall and Horizontal receptacles?

I am going to rewire some rooms and add more receptacles. Would it be possible to use a right angle drill to drill holes through the studs for running cable behind a finished wall? I though maybe I could fit the drill into holes for horizontal receptacles and drill each direction to feed the wire and put in a box between every other stud. Does that sound like a dumb idea? I am hoping to save a lot of cable and reduce my circuit length this way rather than going up to the attic and back down for each receptacle in the circuit.
 
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  #2  
Old 01-28-14, 07:14 AM
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I would probably suggest you do what most electricians would do. Cut a hole in the drywall in the middle of a wall then drill both ways with a long flexible auger bit. Run continuous wire from outlet to outlet and avoud unnecessary junction boxes. Then patch the drywall.
 
  #3  
Old 01-28-14, 07:33 AM
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plaster walls

Thanks for the info. about the flexible auger bit. I hadn't seen that. It looks like it might work for this as long as it doesn't tear up the hole edge too much as it spins. I want to minimize the amount patch work, because I have plaster walls, and I HATE doing patch work!
 
  #4  
Old 01-28-14, 10:56 AM
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Thanks for the info. about the flexible auger bit. I hadn't seen that. It looks like it might work for this as long as it doesn't tear up the hole edge too much as it spins.
The cutting end of a flexible bit is only about 4" long. They're made to flex, and anything more would limit that, so they shouldn't do any damage to the opening in the face of the wall.

That said, there are some things to consider before choosing to use a flex bit. One is that they're made with small holes in the end so you can tie your cable onto one and use the bit to pull your cable. BUT, the last time I checked, only Milwaukee Tools made theirs with a hole in each end, giving you the choice to pull in either direction. The point is, look for a bit that has a pulling hole in each end.

Another is that you may need to make your horizontal holes above or below the level of the receptacles, so that you have the necessary space to bend the cable into the boxes. This can result in having to make an opening above each of your existing receptacles.

Also, the holes need to be made in the center of each stud. You should be able to see that on the first one and, with practice, you can learn to feel with the end of the bit for the center of the second one before you drill it. Beyond that, the position of the bit in the first two holes will limit your ability to both feel for center and adjust for it.

That's why most of us use these bits to drill through top plates, sole plates, and sets of joists. To add more receptacles to a finished wall, we run the cable up from the basement or crawl space, or down from the attic, whenever possible. Cable may not be inexpensive, but it's a lot cheaper than a good job of patching up the wall will be.
 
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Old 01-28-14, 11:06 AM
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You may want to think about pulling the baseboards and running behind them or drilling the studs.
 
  #6  
Old 01-28-14, 11:35 AM
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Sounds like a lot of work to avoid some extra wire. You also need to be sure there are no other wires attached to of passing through those spaces. Or plumbing. Right angle drill, bits, extension bits, vs up through an attic, assuming it is right above your work.

Bud
 
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Old 01-28-14, 04:48 PM
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Huh, I thought I'd be able to use a flexible bit extender or auger bit to put in a couple holes from each side and then just feed a cable through, across the two studs without a lot of pain and saving a ton of cable and reducing my voltage drop quite a bit as well.
 
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Old 01-28-14, 04:53 PM
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I didn't want to worry about cracking the molding, as it would be hard to replicate. I could try it, but I am hesitant.
 
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Old 01-28-14, 04:55 PM
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Voltage drop in a house is typically not an issue.
 
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Old 01-28-14, 04:56 PM
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Nashkat1, I could go from the top, but I figured I'd be adding an extra 14 ft. of cable for every receptacle, which seemed excessive. Maybe I'm not thinking of it correctly. Maybe I'll try a few holes with the flexible bits and see how it goes. I might abandon it and switch to going to the attic and maybe putting in fewer receptacles.
 
  #11  
Old 01-28-14, 04:59 PM
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voltage drop

I guess I was trying to follow the NEC as much as possible, but maybe I'm overdoing it on the voltage drop. I had planned to run 12 gauge cable no longer than around 130' to limit the drop. If I go horizontally, i can get the circuits to under 100'. That provides less than 3% drop for each circuit if I assume maybe 9 amps or so on a circuit. I don't remember the exact calcs I did a few weeks ago.
 
  #12  
Old 01-28-14, 05:07 PM
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sub panel

Since you guys seem to know some electrical, can I ask you about my subpanel? I was planning to put in a 60A subpanel in my attic to supply the finished attic and second floor of my house. I was planning on running a 4-gauge Al SER cable ~50-55' from my basement main panel. Am I correct in thinking this will comply with the NEC 310.16 table, assuming both panels and all breakers are rated for 75C?
 
  #13  
Old 01-28-14, 05:32 PM
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I was planning on running a 4-gauge Al SER cable ~50-55' from my basement main panel.
That will work. It's rated at 55 amps and can be protected at 60 amps.

I thought I'd be able to use a flexible bit extender or auger bit to put in a couple holes from each side and then just feed a cable through, across the two studs without a lot of pain
Good luck with that! I see nothing but pain and headaches doing it the way you describe, not to mention repairs to the plaster walls after you finally finish.
 
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Old 01-28-14, 05:46 PM
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CasualJoe, isn't it rated at 65 amps if all of my terminals are rated at 75C? Do I have to include my branch circuit terminals (ie receptacles, etc.) as well? I can't protect at 60 if it's rated for 55 if I'm using it for convenience receptacles, can i?

Why will i have repairs to the plaster walls? I just want to put in a receptacle b/w every other stud and then go back up to the attic and turn the corner to do the next wall. it's a lot of receptacles, but i'm good at cutting nice holes for receptacles.

i can try one and see how it goes. maybe i'm way off base. I've never used an auger bit, so i'm really in the dark here. you guys probably have.

i can go down through the attic if it doesn't go well i guess. i don't want to repair any plaster!!!

though, I have thought about removing the plaster from the exterior walls only so that i can insulate the walls while i'm at it with some spray foam insulation. that would be a huge mess though. i think blown in cellulose would be a LOT less pain.
 
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Old 01-28-14, 05:57 PM
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isn't it rated at 65 amps if all of my terminals are rated at 75C? Do I have to include my branch circuit terminals (ie receptacles, etc.) as well?
If I am not mistaken, for SEU or SER cables you use the 60 degree column like you would with NM-B cables. It would be rated at 55 amps. The next standard breaker size is 60 amps, protect it at 60 amps.

Why will i have repairs to the plaster walls?
You are trying to run horizontally in a finished wall. At best, this would be very difficult for a professional, I wouldn't even attempt it. I would expect you to have more than a few holes in the walls by the time you get finished either to accomplish this task or repair what may get damaged.
 
  #16  
Old 01-28-14, 07:25 PM
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You need to use the 60 degree ampacity for the feeder cable, not the 75.
 
  #17  
Old 01-29-14, 07:14 PM
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ampacity

pcboss,

can you help me understand this ampacity issue? it's confusing. I was under the impression that as long as I have 75C ratings on all components of my circuit (maybe not the end outlets and light receptacles) that I could use that column as long as the feeder is not NM-B cable. Is this not true? why not?

I'm not trying to be argumentative or a jerk; I just want to understand the rules.
 
  #18  
Old 01-29-14, 07:37 PM
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The NEC article for SE cable states that the 60 degree ampacity be used, regardless of higher rated terminations.
 
  #19  
Old 01-29-14, 08:02 PM
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se article

what is the SE article?

Is it ok to use 4 gauge Al SER cable for a 60A subpanel?
 
  #20  
Old 01-30-14, 03:54 PM
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panelboard height

and one more question: I am under the impression that the subpanel can be installed at a height less than 6.5' in a dwelling. Is that true? I want to install it in the corner of my attic ( i have a square hip roof with knee walls all around the inside ) and the panel will open to 90 degrees but not much further and will have 36" in front of it and 30" off to the right side of it. I just can't get it up to 6.5', as the hip roof starts going up there (at the knee wall intersection).
 
  #21  
Old 01-30-14, 05:05 PM
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The top breaker can be no higher than 6' 7" so it sounds like you are fine.

The SE article is the part of the electric code that covers the installation and usage of that type of cable.
 
  #22  
Old 01-30-14, 05:11 PM
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thanks

Thanks for all of the information!
 
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