Is there a trick to stuffing the caps and wires into an electrical box? So far I've done a few outlets with junctions (3 x 2 x 2.5 box, one 14-2 cable in, one 14-2 out, 3 caps, 1 one-inch duplex outlet with pigtails) and my fingers hurt.
I've left seven or eight inches of free cable inside each box (six is the required minimum but the guide says to go with eight if possible) and the pigtails are about three inches, and I'm using Marette 331 caps (not so big). I've tried folding the wires accordion-style in advance of connecting the outlet and that helps a little, but I still feel like I'm cramming the stuff in.
Also, I keep thinking the inspector will come in and say, "Why did you connect this outlet to that circuit? You should have run them this way instead." It's not a bad layout (I used to design printed circuit boards for a living) but I could have used shorter runs if I hadn't been particular about serving each corner of the space (two rooms in a 26 x 10' area) with each of two circuits. As long as I have a fair distribution in each room and observe the technical requirements, does the inspector care which circuit goes where?
I think I'm suffering from Inspector Anxiety.
-- "For it is only of the new one grows tired. Of the old one never tires."
You should have consulted article 314 of the National Electrical Code prior to the installation of your outlet boxes. By code definition they are too small. Table 314.16(A) tells you that you are allowed six number 14 conductors in the box. However you must deduct two from that total for each wiring device (Outlet) in that box and also deduct one wire for an internal wire clamp. If you used a connector that has its clamping mechanism outside of the box (Such as a romex connector) then no deduction for a clamp is necessary. Fortunately the ground wire only counts as one regardless of the amount. The pigtails don't count, but they sure do add to the space.
You should have used 3.5" deep boxes which is permitted to have nine number
14 wires. You wouldn't have had any problem "Stuffing" the wires, pigtails, and outlets into deeper boxes and you would have been code compliant. If depth was a concern, you could have used 4" x 4" x 1.5" square boxes with plaster rings based on the depth of your finished wall.
Plastic outlet boxes tend to have more volume than the metal outlet boxes. They usually have the cubic inch volume stamped on them.
I don't know what guide you used, but you should have picked up a copy of the National Electrical Code (NFPA 70) also. You can get it on Amazon.
John, by my code book (Canada), he is allowed four conductors and four nuts, and he meets that. The code book I use accounts for the internal clamps and the duplex receptacle already. Are you using pigtails on the ground as well? If so, and if this is a duplex plug, you could leave one of the romex ground wires long, wrap it around a box ground screw, and then attach the distal end to the ground screw on the plug. The other ground wire can wrap around another ground screw on the box so you don't need the ground pigtail. Just be sure you have only one wire wrapped around one screw, as 'doubling up' on a screw is a no-no.. Electricians in my country do this all the time, and you would only need two nuts to fill the box. Get used to the sore fingers, it's the price you pay to enjoy manual labour. Just to clarify, I am not an electrician and do not know all the details of US code.
Dave
"John Grabowski" wrote in message news:5jb8d.5110$g% snipped-for-privacy@news4.srv.hcvlny.cv.net...
Thanks. I'm working to Ontario code and I have carefully read a simplified guide, last updated 2003, with box fill tables that let me do this. There's even an illustration that shows basically the boxes I'm stuffing, and it says to use 2 x 3 x 2.5 for the job. In my several trips to Rona (the Canadian equivalent of Home Depot) I have never even seen a box 3.5" deep. (I did pick up some 3" deep boxes for junctions containing a switch.)
Running a cable into and out of a box with a receptacle in it has got to be a fairly routine thing -- practically unavoidable. You don't mean they require
3.5 deep boxes in the States? (If so, they must be easier to stuff!)
BTW, in the Ontario code, the bonding wires don't count in the box fill calculations. For those purposes I have only four wires. The loomex cable clamps are built into the box, at the back.
"John Grabowski" ( snipped-for-privacy@> You should have consulted article 314 of the National Electrical Code prior
-- "For it is only of the new one grows tired. Of the old one never tires."
Thanks. I'm using a pigtail for the ground. The book I'm working from is explicit: the bonding wire goes first to the box, next to all the other bare wires, third via pigtail to the receptacle. So that's the way I'll do it -- just call me chicken. :-)
It isn't explicit about whether, if there are two bare wires coming in, only one of them should go to the box. The text doesn't say, but the picture shows it that way. I've taken the incoming cable (from source) to the box, but there are two screws -- I could connect the other bare wire to the box before the pigtail. Would that be a good idea or not?
Also, about "wrapping around" the screw, is a complete 360 needed, or a
270, or is it OK just to run the wire under the screw at one side?
I was afraid of that. Thanks.
-- "For it is only of the new one grows tired. Of the old one never tires."
A 3 1/2" deep box would be difficult to use on 3 1/2" deep 2" x 4"s, especially with ground screws and clamp screws sticking out the back. That means the drywall would be hitting, and pressing on the back and could cause the screws to pop a hole through the drywall. They would be fine for 2" x 6" studs.
If you don't have many to do, you might look for some ready-made pigtails made with stranded wire.
Wrap it around as much as you can without it overlapping itself. I generally go 270 if the wire stops at the screw, or 180 - 200 if the wire is wrapping around the screw and then continuing on to the device.
BTW, your 2x3x2.5" box should be fine for two #14 cables and a device. It's marginal (and probably too small) for two #12 cables and a device.
Nope, the box usually projects out from the front of the stud a distance equal to the thickness of the drywall installed, or to be installed, usually 1/2". Therefore there is a 1/2" gap between the back of the box and the opposite side drywall.
I should have checked my shop first. Apparently, like lumber, they use nominal sizes for electrical boxes too. I have a 3" blue plastic box, that when measured is actually 2-7/8" from front to back (outside measurement). I also have a 3-1/2" (20 cu in) tan plastic, 2 hr fire rated box that when measured, is 3-1/4" from front to back (outside), so the gap between the back of a 3-1/2" box and the opposing drywall in a
2x4 studded wall would be about 3/4", after allowing for the face drywall projection.
There's another puzzle for me. On an inside partition, The 3" box brings the incoming cable pretty close to the edge of the 3.5" stud -- closer than the 1.25 inch allowance, I believe. Where the cable is too close to the stud edge and not free to move aside, we're supposed to protect it against errant drywall screws using a metal plate attached to the stud. Would they be required behind the 3" box?
No wonder people hire electricians to do this. . .
-- "For it is only of the new one grows tired. Of the old one never tires."
On Mon, 4 Oct 2004 08:48:39 -0700, James Owens wrote (in article ):
James -
I am not familiar with the code used in Ontario. Under the NEC, you would have to protect NM cable anywhere it was within 1 1/4" of the rough framing surface even "behind" a box. (I assume you're concerned with the side of the wall opposite to the box opening.)
To return to your original question: I'm surprised the Ontario code allows the box fill you're using. As another poster observed, it would not be allowed under the NEC, and I was under the impression that Canadian codes were generally more restrictive. More to the point: electrical codes are minimal requirements for safety. They are not design manuals. I never use single gang boxes (even the 2 1/2" deep ones) for duplex outlet installations. They just don't have enough room for wire and device installation. This is especially true with larger strap-mounted devices such as GFCI receptacles.
IMHO you should be using 4 x 4 x 1 1/2" boxes with 1/2" device rings (or thicker if your wall sheathing requires) for your application. Not only does the added space allow for easier installation, but it also allows for future expansion (adding another duplex, daisy-chaining another box, or whatever.)
By way of illustration, the NEC requires 2 cubic inches for each #14 conductor, with 1 conductor allowance for the aggregate of grounding conductors, 2 allowances for each strap-mounted device (such as a duplex receptacle), and 1 allowance for each internal cable clamp. Your application therefore involves 9 conductor allowances for 18 cubic inches. A 3 x 2 x 2
1/2 box is 12 1/2 cubic inches, while a 4 x 4 x 1 1/2 with 1/2" sindle device ring totals 24 1/2 cubic inches.
As far as cramming all those wires into the existing boxes, I can only suggest layering-in each set of conductors in a large flat loop against the back of the box, with the wirenut above or below the device. Then you're left with the device pigtails which have to be folded in accordion-like as you press the receptacle in. (A picture would be worth 1000 words...)
Again, I don't know what the Ontario code might say about how you've circuited the rooms, but under the NEC the only specifics for residential circuits involve special-purpose rooms such as bathrooms, laundry-rooms and kitchens/food-preparation areas. General-purpose receptacle circuits can be run any way you wish, provided the number of circuits is sufficient for the load and the load is approximately evenly divided among the circuits. (In the absence of any specific devices to be served, the load would be the 3 Volt-Ampere per square foot general lighting load.) There are requirements for the minimum number of receptacles, however. Basically, there must be an outlet for every 6 lineal feet of wall, with the outlets spaced as evenly as possible. You might check your code for a similar requirement...
Is this really true that your have to protect the back of a 3" or 3.5" box for interior walls? I didn't see my builder do it 4 years ago when they built my house, that uses 2x4 studs. I don't think I see anyone do it .. I did not see anything like that at Home Depot.
There are restrictions involving the receptacle size -- the tables I'm using assume are for receptacles or switches no deeper than one inch. For GFCI a bigger box would probably be required. Switches are a lot thinner than receptacles, but they're treated interchangeably.
The rule here is that any point on the wall has to be within six feet of a receptacle, measured along the wall (no cutting corners), with no obstacles (columns down to the floor, say). Also any isolated bit of wall longer than three feet has to have a receptacle. This is just for living spaces. The simplified code for kitchens takes up pages and pages. Thank goodness I don't need to know.
BTW, our figures are really in centimeters, but we just ignore that.
-- "For it is only of the new one grows tired. Of the old one never tires."
Does specifying the box size as 3 x 2 x 2.5 imply the box is metal? The OP spoke of grounding the box, so it is metal, I am just wondering about the terminology.
Why is a 3 x 2 x 2.5 metal box only 12.5 cubic inches? 3*2*2.5 = 15. Is the volume loss due to slight undersizing, or rounding the corners, or what?
In your conductor allowance, you made two allowances for clamps for the two cables. Do plastic romex clamps require an allowance? With metal clamps (two screws), can you put the clamp portion outside, and does that avoid an allowance?
I always use stranded wire because I don't have all these problems pushing the receptacle or switch back into the box. The only reason why Romex is even used is because it's slighly cheaper than stranded wire, and home buiulders are penny pinchers. Always buy the receptacle/switch box that you can put in a given location. My biggest gripe on boxes is that if you like the metal ones like I do (I would never use a plastic box) then it's either a "switch" box that isn't tall enough or a "handy" box that isn't deep enough. At least you get to pick which direction you want to be constricted in.
I assumed a 3*3*2.5" box would be about 14 in3, but I looked it up and surprise: It is 12.5 for almost all of them.
You can completely remove the bottom clamp from a switch box and have both cables come in from the top and save one allowance. I've never tried moving a clamp to the outside of the box...
On Mon, 4 Oct 2004 13:53:16 -0700, zxcvbob wrote (in article ):
Wayne & Bob -
I was referring to metal boxes as covered by NEC 370-16. The table covers only certain common metal boxes. Other boxes (including plastic) must have their capacity indicated on them.
The trade sizes of boxes are the exterior measurements, and the cubic inch capacity is taken from the interior measurements. The difference is wall thickness.
The deduction for clamp fill applies to internal clamps only. Plastic or metal Romex clamps with an exterior clamping mechanism do not require a deduction. Not only can you install a "two-screw" metal Romex clamp with the mechanism outside the box, that's the way they're supposed to be installed! (The screws go outside and the locknut inside...)
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