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Surface Mounting Duplex Receptacles on Plaster Wall in Garage

Surface Mounting Duplex Receptacles on Plaster Wall in Garage

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  #1  
Old 03-26-06, 07:23 PM
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Question Surface Mounting Duplex Receptacles on Plaster Wall in Garage

The inside of my two car garage is plastered, walls and ceiling. I want to add some duplex receptacles along the wall. I have just completed a new subpanel in the basement adjacent to the garage. My plan is to run 14-2 romex from the panel into the garage and then transition it into either EMT or plastic. I have a bender and am familiar with working with EMT.

1. Can I just run the romex into 1/2" EMT and then to the first receptacle?

2. Do I have to run the romex to the first handibox and receptacle, then use THN between the first box and additional boxes?

The romex would pass thru a wall along a ledge and then into the EMT. I could make it so that the EMT appears to go into the wall so that you can't see the transition.

Thanks
Mark
 
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  #2  
Old 03-26-06, 07:45 PM
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Originally Posted by n1ml
1. Can I just run the romex into 1/2" EMT and then to the first receptacle?

2. Do I have to run the romex to the first handibox and receptacle, then use THN between the first box and additional boxes?

I could make it so that the EMT appears to go into the wall so that you can't see the transition.

Mark
My three cents:

1. There is disagreement on the topic of stripping the romex. The rest, maybe someone else can chime in.

2. THHN/THWN is a good choice for most conditions when using raceway. For normal distances use 12 AWG and a 20A breaker. Why use 14 AWG? You might want to run a shop vac and a table saw at the same time one day.

3. If it were my place, I would just use a surface mount box for the transition or continue the conduit to the load center. Come through the wall with the Romex and use a plastic or metal clamp into a rear knockout, then terminate your raceway on a side KO. You could also use an old-work box to do the same thing, and offset your conduit so it looks like it disappeared, but that's a bit more mess, and then you might as well just keep going through the wall. You cannot run EMT or a conduit body thru a faceplate into a box. If you want to do that and local codes allow you must use a stub of flex (Greenfield) so the faceplate can be removed.

Also check local codes. For example PVC and Romex are not allowed for exposed installations in garages in my municipality.

OK one more thing, check your box fill, especially when using handy boxes and 12 AWG if you go that route. I am not sure if it's still called a handy box but you will be much happer with a 4x4 with rounded corners and a galvanized faceplate if that's the look you want.
 
  #3  
Old 03-27-06, 04:23 AM
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wiremold

As far as stripping romex goes, the conductors inside romex are THHN.
Strip it, you get THHN, just like off the spool.

You can use an old work box in the wall, then add a wiremold extension device box.
You can then come out of the wiremold box with wiremold raceway into other boxes.
Doesn't require any fancy bending or patch work that way.

And yes, use 12 wire
 
  #4  
Old 03-27-06, 04:36 AM
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You cannot strip NM cable and use the individual conductors. The wire inside may very well be THHN, but it is NOT marked as such and therefor may not be used as such. This is a code violation. If you happened to find NM cable that had inside conductors marked (and where would they mark the ground?) as THHN then you could use the marked conductors.

If you are planning on conduit once you get to the garage, then I recommend NM from the panel through the wall to the first surface mount box, feeding the box from the rear. Then use THHN inside conduit for everything else.

I also think that you should use 12 gage wire on a 20 amp circuit, and stay away from 14 gage wire. Do the same amount of work with 12 gage wire/cable and get 33 percent more power.
 
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Old 03-27-06, 05:10 AM
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> where would they mark the ground?

Obviously bare wires don't have a temperature limit on the insulation.

Are we saying that a bare copper has to be marked or else it can't be used in plastic conduit as an EG conductor?
 
  #6  
Old 03-27-06, 05:23 AM
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THHN is a stranded wire, I think. My understanding that I need to use the screws to secure to the outlet, correct? Can the stranded conductors be put into the back clamp down holes in the receptacles? (You strip, poke into a hole, then tighten the side screw to tighten the internal clamp on the wire.
I will use the 12 AWG as all suggest, with a short run of romex to the first receptacle, back fed. Can romex be used in conduit without stripping it? My guess is no, but I thought I would ask.
Thanks
 
  #7  
Old 03-27-06, 05:48 AM
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The question of whether NM or UF can be used in cionduit is often debated. You can certainly use conduit for protection, such as for UF cable down the side of the house to the bottom of a trench, but people will disgree as to whether you can place NM inside conduitfor an entire run. I would not.
 
  #8  
Old 03-27-06, 05:55 AM
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NM-B (Romex) shouldn't be stripped when used in conduit. The wire is not listed to be used that way. NM-B is allowed in lengths of conduit for protection, and this would include a length used to change from NM-B to conduit as a wiring method. And, by the way. the code requirement for NM-B is that it have 90 Deg C rated insulation. This does NOT necessarily mean that the insulation has to be THHN, though it frequently is.

Have you given any thought to using ENT (smurf pipe) to run from the panel to the point where you change to EMT? Then you could pull THHN all the way - BTW, it comes in both solid and stranded. ENT is a hand bendable (usually blue color - hence "Smurf") PVC conduit that pulls almost like NM-B. This would allow you to pull an additional circuit or 2 in the future if needed with not a lot of effort. The only hitch might be that the rule for not having more than 360 deg. of bends between pull points applies.

Don't use handy boxes. Use a 4" square box with a single or double gang mud ring or industrial cover. The handy boxes, except the very deep ones, aren't big enough to allow feed through wiring. Connections and installing receptacles is much easier also.
 
  #9  
Old 03-27-06, 06:08 AM
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THHN is not used inside NM. The "N" stands for Nylon, and at least I've never seen nylon sheathed conductors in NM. Its more likely MTW. Still 90 deg PVC.
 
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Old 03-27-06, 07:35 AM
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Originally Posted by n1ml
THHN is a stranded wire, I think.

My understanding that I need to use the screws to secure to the outlet, correct?

Can the stranded conductors be put into the back clamp down holes in the receptacles?
1. THHN can be solid or stranded. I prefer stranded in #12 because it pulls easier. Solid, on the other hand, is easier to terminate and you can 'shape' the wires in panels and j-boxes more easily.

2. You need to use the 6-32 screws on the mounting yoke to secure the outlet to the box. I am not sure how else you would do it. Or are you talking about using the mounting screws for grounding purposes, eg. bonding to the metal box? In that case I have used all self-grounding devices, but unless code has changed again [2002 NEC 250.146 (A)] you can still use mounting screws in surface-mount metal boxes. I haven't seen a GFCI listed for self-grounding so that might be helpful there.

3. If you do use stranded it is much easier to terminate with backwire-able receptacles such as Leviton BR15, 5262 and similar switches. The BR15s I got at the Big Box but the switches (also self-grounding) I had to get at the supply house.
 
  #11  
Old 03-27-06, 07:53 AM
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  #12  
Old 03-27-06, 08:34 AM
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You answered my question on the wire hold down screws. I was not talking about the receptacle mounting screws (I was not clear). I will use the THHN as described and the type of duplex receptacles you call out.
I did have another idea. The garage has a cement wall coming up about 4' from the floor. There is a 2x6 plate on the cement wall and then there is a 2x4 sitting on top of that.(The 2x4 is inside the plastered wall. The plaster wall comes down and rests on the 2x6. There is an inch of 2x6 exposed sitting on the concrete. Could I run romex along the wood and staple it and run it to a couple of 4"x4" boxes? It sure would make the whole job easier. It is a garage. I guess the major question is "can there be an exposed romex running along this wood that sits on top of a concrete wall?"
 
  #13  
Old 03-27-06, 08:51 AM
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Originally Posted by n1ml
"can there be an exposed romex running along this wood that sits on top of a concrete wall?"
No, the wire must be protected from damage. If you want to run cable like this, then use BX
 
  #14  
Old 03-27-06, 07:18 PM
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The rules for installing various types of armored cable and flexible conduit are the same as they are for NM-B (Romex). You need to check the code references for the material you are going to use before you decide it OK to use it in a given situation. Even EMT is now prohibited in situations where the possibility exists for some kinds of damage

NEC 2005

ARTICLE 320 Armored Cable: Type AC
320.12 Uses Not Permitted.
(1)Where subject to physical damage

ARTICLE 330 Metal-Clad Cable
Type MC 330.12 Uses Not Permitted.
(1) Where subject to physical damage

ARTICLE 334 Nonmetallic-Sheathed Cable: Types NM, NMC, and NMS
334.15 Exposed Work.
(B) Protection from Physical Damage. Cable shall be protected from physical damage where necessary by rigid metal conduit, intermediate metal conduit, electrical metallic tubing, Schedule 80 PVC rigid nonmetallic conduit, or other approved means.

ARTICLE 348 Flexible Metal Conduit: Type FMC
348.12 Uses Not Permitted.
(7)Where subject to physical damage

ARTICLE 352 Rigid Nonmetallic Conduit: Type RNC
352.12 Uses Not Permitted.
(C) Physical Damage. Where subject to physical damage unless identified for such use.

As to WHERE an electrical cable or conduit is subject to damage, that is left to the discretion of the "Authority Having Jurisdiction" (the inspector type folks), but is typically above 6'-6" in a garage.
 
  #15  
Old 03-27-06, 07:24 PM
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nylon?

nm stands for non-metallic sheathed cable
there is no limitation against installing nm in conduit
 
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