# New Recepacles in a shallow wall



## HouseHelper (Mar 20, 2007)

trosenda said:


> Hi,
> 
> I'm wiring a basement room that has only 1 1/2" from a concrete foundation wall to the finished surface. I believe it is 3/4 furring and 3/4" plaster. I would like to place 15 amp receptacles in these walls but there will not be enough space for even the shallowest boxes. Can I cut out the location for the boxes and then add a 1" thick spacer block to the finished wall with the same size cut out as the electrical box requires to allow for the depth? Then wire as usual?


I would seriously look into using surface wiring (Wiremold) to do this.


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## trosenda (Oct 26, 2009)

If you're recommending surface mounting is that because my original suggestion is not an appropriate solution? or is surface mounting just the usual way of solving such a problem?


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## HouseHelper (Mar 20, 2007)

Since the walls are already finished, I think the Wiremold would be an easier and better looking alternative. You could have a difficult time fishing wires behind the plaster (are the furring strips vertical or horizontal?) and the 1" blocks would look weird.

If you really don't like Wiremold, and don't mind fishing the wire, you could use 4x4x1.25 square boxes with 1/8" mudrings and patch the cutout area, leaving only the mudring opening.


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## Scuba_Dave (Jan 16, 2009)

One small box I know of is only 8 cu inches & 1.25" deep
14g wire = 2 per hot plus 2 for device + 2 for ground
So it is only rated for a wire going into the box










The next step up for 2 wires is rated at 18 cu inches & is 2 7/8" deep
Its rated for up to (2) wires - 14g or 12g 
2 for each hot x 4, 2 for device, 2 for grounds = 12 cu inches
12g would be 2.25 x4, plus another 4.5 = 14.5 cu inches

That would stick out about 1.5"
You could cut out a piece of wood block and have it spaced out as you say
Could be a PIA to fish the wires
But I think I'd prefer that over wire mold


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## Jim Port (Sep 21, 2007)

The box posted by SD would need to have 10 cubic inches before it could be used. Six ci for the cable and 4ci for the device, assuming #14 wire.


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## trosenda (Oct 26, 2009)

Thank you for the clarification on junction box volume requirements Jim. Is there a good resource or simple formula for calculating box volome requirements to meet NEC given a number of conductors and their size entering the box as well as the device?


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## Scuba_Dave (Jan 16, 2009)

Yup he's right...device (outlet) counts as 2 current carrying conductors...not 2 cu inches
1 per receptacle ?
I have only used it as a switch box due to a pocket door
Switch counts as 1 from what I have read ? (*nope I'm wrong* - can't even read what I copied & pasted here :laughing

*The Chart Says That (NEC Article 314.16.B):*
14 Awg. = 2 Cu. In. per conductor,
12 Awg. = 2.25 Cu. In. per conductor
10 Awg. = 2.5 Cu. In. per conductor
8 Awg. = 3 Cu. In. per conductor
6 Awg. = 5 Cu. In. per current carrying conductor counted.

*Calculating Current Carrying Conductors*

If you are using all conductors of the same size in your box, then you must count the number of current carrying conductors [all colors including white but not counting green or bare] entering your box. Also do not count conductors that neither enters your box nor leaves your box. [pigtails only, these are ignored].
Now add to your number of current carrying conductor list, by counting all of the grounding conductors as one conductor [green or bare], no matter how many grounding conductors, just add the one current carrying conductor to your total number of current carrying conductor list. Remember that all grounding conductors [green or bare] must be counted as a total of one current carrying conductor. NEC Article 314.16.B.5
Clamps are also counted the same as grounding conductors, one current carrying conductor must be added for the total of all clamps found in the box. All clamps found within your box that are entering the box at least ½”, no matter how many, count as a total of one current carrying conductor, only, for all of these clamps. Now add this one conductor count to your total number of current carrying conductor list, if any of these clamps are present. NEC Article 314.16.B.2 A single gang plastic or fiber box will have no clamps to consider. They are exempt from a clamp requirement. NEC Article 314.17.C.Exception

Devices yokes must count as 2 conductors for each device. Count the number of devices {switches or receptacles}. Multiply the total number of devices times 2. The answer from multiplying the total number of devices by the 2 is the total number of current carrying conductors you must add to your total number of current carrying conductor list. NEC Article 314.16.B.4
Now this final total of your current carrying conductor list is the answer to the total number of current carrying conductors installed in your box.


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## Code05 (May 24, 2009)

switch counts as two conductors also.


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## Jim Port (Sep 21, 2007)

A device like a switch or a receptacle counts as 2 wire volumes of the largest conductor it is connected to. Even a GFI only counts as 2 volumes.

Scuba Dave has provided a very comprehensive chart for conductor fill calculations.


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## jbfan (Jul 1, 2004)

The closest thing I have found is a carlon b117rsw. It is 17 cu inches, but only 2 inches deep.
Still deeper then you want or need.


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## 220/221 (Oct 9, 2007)

> Can I cut out the location for the boxes and then add a 1" thick spacer block to the finished wall with the same size cut out as the electrical box requires to allow for the depth?


I suppose.....but it would look like hell. Even though they are "too small" , I would just use the shallow boxes pictured. There is really plenty of room in them for one cable and a device.

I have also seen a box like that that was wider and had enclosed space off to one side to give it more cubic inches.

If you truely have a full 1.5" you can probably use a standard shallow 4 square box with a flat mud ring You will of course have to tape the sides of the mud ring or use double duplexes.


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## kbsparky (Sep 11, 2008)

Use a wiremold extension box on the extra shallow box shown.

The catalog numbers are: 5751 (buff) V5751 (ivory) or 5751-WH (white). You can conceal the wiring, and the box will stick out about an inch as originally stipulated.


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## busman (Nov 7, 2008)

kbsparky said:


> Use a wiremold extension box on the extra shallow box shown.
> 
> The catalog numbers are: 5751 (buff) V5751 (ivory) or 5751-WH (white). You can conceal the wiring, and the box will stick out about an inch as originally stipulated.


Are you suggesting a metal extension on a plastic box?


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## Scuba_Dave (Jan 16, 2009)

busman said:


> Are you suggesting a metal extension on a plastic box?


Yes - that is exactly what he is saying


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## busman (Nov 7, 2008)

And how's it grounded?


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## Code05 (May 24, 2009)

drill and tap for a 10/24 screw or bolt on ground wire.


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## busman (Nov 7, 2008)

Ground screws are 10-32 thread and that would not be using the product IAW the listing.


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## Code05 (May 24, 2009)

You are probably correct 10/32. What does IAW mean?


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## 300zx (May 24, 2009)

Code05 said:


> You are probably correct 10/32. What does IAW mean?


 International Alliance of Women or Islam Awareness Week :laughing: Google it


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## Code05 (May 24, 2009)

300zx said:


> International Alliance of Women or Islam Awareness Week :laughing: Google it


:huh:
Not very helpful.


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## Scuba_Dave (Jan 16, 2009)

I don't see it really as being much different from a metal faceplate


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## Code05 (May 24, 2009)

Scuba_Dave said:


> I don't see it really as being much different from a metal faceplate


I agree, but code says the plate is grounded by the receptacle and a box is not. I do not agree, but that is what it says. You can use a self grounding receptacle and just ground the box, but it does not work backwords, you can not ground a box with a receptacle. Crazy, but true.


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## 300zx (May 24, 2009)

Code05 said:


> :huh:
> Not very helpful.


Definition of: *IAW* "In accordance with."


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## Code05 (May 24, 2009)

300zx said:


> Definition of: *IAW* "In accordance with."


Thank you. New to these forums and do not know all the abbreviated lingo.


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## busman (Nov 7, 2008)

The reason I mentioned the listing and the screw type is this: you can tap a hole in piece of aluminum foil, but it won't make a sufficient ground. Holes tapped in a Gem or 1900 box have sufficient thickness of steel to engage enough threads on the 10-32 (the 32 being 32 threads per inch) to make a good ground connection. The wiremold baseplate is very thin stamped steel and not thick enough.

Mark


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## HouseHelper (Mar 20, 2007)

Just use Wiremold's plastic box extension.


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## 220/221 (Oct 9, 2007)

Wiremold = :jester:


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## spark plug (May 5, 2009)

Jim Port said:


> The box posted by SD would need to have 10 cubic inches before it could be used. Six ci for the cable and 4ci for the device, assuming #14 wire.


How about using the box that Scuba Dave posted + a Wiremold Extension box? :devil2: The devillll is in the Details; Don't Drink and Drive, Ever :drink:!!!


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## Scuba_Dave (Jan 16, 2009)

Well I saw a new (to me) box at HD today - $2.42 or so
17 cu inches & it said for walls 1.5" deep
Some of the box will actually be behind the sheetrock on one side
Its closed off from the sheetrock - just a pocket on the side for wires











Number B117RSW - it is New !! per Carlton - page 6

http://www.carlon.com/Master Catalog/Zip Boxes_2B1.pdf

BTW - the 8 cu inch is labeled (by HD) on the shelf for low voltage use


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## spark plug (May 5, 2009)

*Standardization of Plastic vs. metal boxes.*

Scuba Dave (Poster #30) Thank you for posting the link for All the various boxes. It's obvious that low voltage boxes have less stringent requirements in terms of enclosure (to protect against arcing/sparking) than standard voltage. That is why they're marked "Low Voltage". As I said in another post that I believe that is the main reason grounding requirements have been changed in the past few years. Because (it really started that way) PVC and other non-metallic materials are becoming more standardized for use in water supply and drainage. Adding to that is the fact that plastic (electric) boxes have practically replaced metal boxes in both Standard and low voltage. (No matter what):drinkon't Drink and Drive, Ever!!!


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## InPhase277 (Feb 9, 2008)

The wiremold extension could be bonded by through-bolting a pan head 10-32 with a washer and nut.

If it were me, I'd probably just use the Carlon box on the previous page.


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