wiring – packing wire into device box
caseyr
| Posted in Construction Techniques on
Is there a secret to neatly cramming the wires into a device box/j-box when one has a lot of wire and the wiring is almost at the maximum for the size of box? I usually like to leave lots of space to get the wiring in, but am now faced with a couple of 4×4 boxes with 1″ extensions with 12 conductors and 8 grounds. (It works out that I have about 2.5 sq in to spare) is there some trick to folding the wires to get them to fit in a reasonably orderly fashion, or does one just cram them in and hope for the best????
Replies
fold them against the back of the device in an orderly fashion, making sure the bare ground doesn't get against a screw. (if tight wrap the device in tape) push the whole bundle into the box.
I'm NOT an electrician, just what I see on the job.
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"You cannot work hard enough to make up for a sloppy estimate."
Why not use a bigger box and a mud ring for the switches you need. That way, you aren't forcing the switches and wires into the box. I do this with low-voltage wiring and it makes a big difference. Plus, with coax, you don't want tight bends, anyway. With bare grounds, I don't want any chance of them touching the hot or neutral.
Are you following the box fill requirements of your local code (which I know nothing about)? I've never had a problem with my local requirements, your mileage may vary.
Scott.
Always remember those first immortal words that Adam said to Eve, “You’d better stand back, I don’t know how big this thing’s going to get.”
Well, one thing NOT to do is to force the wires in with your Kleins or needlenoses-- you'll munge up the unsulation and have to start all over again. (DAMHIKT. Man, wire insulation used to be a lot tougher to damage.)
What I do when I have a box that I know will be pretty full is to:
1) Leave some extra outside the box in case you need to pull some in later on.
2) Plan how the wires will best fit in the box once they are all connected up, including how the device will fit in.
3) Cut the wires as short as possible to work with the plan (after making sure that you did Step 1). Connect them up and carefully arrange them neatly in the box, leaving a "hole" for the device and minimal wire for the device, roughly positioned where they will connect to the device. Use a blunt wooden stick, or the rubber handles on your pliers, to carefully pack wires as needed.
4) Connect the device and carfully push it into the box. It helps to "prebend" the wires to the device a bit so they fold up nicely, rather than kink, when you push the device in.
I also like to use the old-style Buchannan B-Cap wire nuts -- the kind with the soft plastic insulation and no huge wings. They take up less space. Problem is, they are hard to find these days. I don't think they make 'em anymore, so I use what I have left very judiciously.
Mike Hennessy
Pittsburgh, PA
Is there a secret to neatly cramming the wires into a device box/j-box when one has a lot of wire and the wiring is almost at the maximum for the size of box?
Are you certain you aren't exceeding the fill of the box? Including the device in the calculation? The point of the box fill numbers is to avoid boxes that are too full - if you are having trouble fitting the wires in, that sure sounds like an overfilled box.
I don't usually see this problem unless there's a bulky device in the box, like a dimmer or a GFCI receptacle. If you have the choice, I repeat the suggestion of using a bigger box. Still, with a 4" square box at least 2" deep, it doesn't seem there should be a problem. How did you manage to have 8 grounds with only 12 conductors? I wrap all the grounds together first, and jam them way back with the wire nut (if any) in a back corner. Then just fold the remaining wires in half after connecting them, and lay them in.
Unlike some other posters, I find today's insulation much tougher than years past. It's thinner, sure, but doesn't seem to compress at all.
With a 4-sq box I don't fold the wires into it, I wrap them around the inside perimeter.
This seems to use the space most efficiently and leaves the center open for the device. The only wires I fold are the pigtails attached to the device itself.
Ed
Like edlee, I use a rolling technique. Take each wire nutted pair or group and roll them into the box, starting with the shortest ones and ending with the longest. If you have cut your wire groups about 1" shorter as you make them up, you will end up with wire nuts laying nearly one behind the other and hole in the center for the device. Even them sometimes it is a PITA getting everything to fit. When that happens I pull everthing back out and look at it as a puzzle. They will all fit,... it just a matter of figuring out which pieces of the puzzle goes where and in what order.
Dave
The basic NEC Code rule is to have at least 6" of wire from the entrance to the box.
The other rule on box fill is rather complicated but see Article 370-16.
But in commercial we avoid this by always using a 2 1/8" deep, 4 square box with a mud ring. One sensible approach is to use a pure [accessable] box above the ceiling to handle most of the connections and just have the necessary connections and wires in the switch/receptacle box. For instance, this will keep the neutrals and all but one ground wire out of a switch box.
If you want, you could consider using Wago connectors to save some room -- especially for the grounds. The next time I am at Home Depot or a supplier, I will invest in abox of their 8 wire version. They have one type with levers. Also looping the wire around the screws will reduce the size of the wire nuts required.
As mentioned above, preplanning and pre bending your wires will help a lot.
If worse comes to worse, a FastCap 3rd Hand develops some 79 pounds of pressure.
~Peter
Check your code for conformity, of course.
Push Gard connectors eat up a lot less space than wire nuts and the flat orientation of the wire connections allow for easier push in.
http://www.gardnerbender.com/whats_new/products/PushGard.shtml
Apparently the Wago connectors that Peter mentions are similar.
Edited 11/14/2007 9:20 pm ET by TomE
Am I missing something, Tom? When I buy duplex outlets, the "pro" style back-wired ones have screw tighteners that pinch a half inch of wire between brass contacts for better wire-to-connector contact like GFCI's use. Backstab connections seem only to be used in cheapo outlets.Wire nuts press the connected wires tightly together over a half inch or so of their ends. The PushGard connectors you link to seem to be like the cheapo back-stab outlets, making contact with with the wire by just an edge of the internal spring contact. Are they really as good as properly connected wire nuts?BruceT
If you aren't comfortable with those you can always use AlumiConns. A lot more $$ though.
If your view never changes you're following the wrong leader
I doubt you are missing anything, the OP had a question and we're all here to try to help.
The connectors I mentioned are one possible solution.
Yes they are similar to the stab back connections of the "cheapo" outlets. I don't recall having to replace a device due to a failed stab connection, most cheapos I've replaced have been due to cracked faces, particularly around the ground hole.
Are they better than properly installed wire nuts? No, but I've seen more failures due to loose nuts/screws/poor installation than those connections that are locked in by the little springs.
I share your concern about the seemingly small "grab" on the wires, time will tell however.
"I doubt you are missing anything, the OP had a question and we're all here to try to help."Sorry if my question may have seemed critical. I did not mean it that way. Seeing the link you posted made me curious about the quality of connection, since back-stab devices are very quick to use, yet the most expensive "Pro Grade" ones use screw-tightened back-wire methods that take more time and I haven't seen a back-stab device for larger than 14ga wire in a while. Now that you mention it, there are a ton of back-stab type outlets in thousands of houses that have been working for 40 years or more. Maybe "Pro Grade" is more hype than performance?
BruceT
Bruce,Your concerns about backstabbed devices are valid. I have witnessed failures in my own home and at customers' homes. These were open circuits due to stabs failing, but I have also seen scorched devices from the intermittent connection at high resistance before it failed completely.I also have wondered just how good the push connectors are. The contacts in the ones that ship with some Halo recessed fixtures look a lot more robust than the stab contacts in cheapo outlets do. The Halo connectors require a firmer shove to engage than the stabbed outlets, too.Bill
I am not an electrician, but I have used the gardner bender push in connectors as well as the wago. I think the difference in this type of connector versus the backstab connections are the strength of the spring and the amount of contact area in the pushin connector. I have used them as a test in various easy to access areas, they are especailly nice for flourescent and incandescent applications. Have sen no problems yet.
I also think that the backstab connections are often compromised by inexpereinced people using them. For example a homeowner stabbing the wire in and then really cramming the device into the box. The pushin connectors have the ability to be folded out of the way which maintains the integrity of the connection, not allowing it to be stressed.
Chris Webb
Chris' Handyman Service
Edited 11/15/2007 3:42 pm ET by webby
Edited 11/15/2007 3:43 pm ET by webby
The only case where I've seen a backstab failure was when someone stabbed the wire into the wrong hole. The wire will (or would on that style outlet) fit into the release hole, but the connection made is obviously poor at best.(Outlet was apparently wired by a regular electrician, or at least not a Saturday afternoon hack.)
If your view never changes you're following the wrong leader
I've seen more back-stab failures in switches than receptacles, though I don't know why that should be.
Ed
Switch is subjected to more motion.
If your view never changes you're following the wrong leader
"...when someone stabbed the wire into the wrong hole."
Like this?
View Image
BruceT
Yeah, and it's a lot harder to remove the wire from that hole than to remove it from the regular hole.
If your view never changes you're following the wrong leader
No worries Bruce.
I do agree with Bill that the potential for the back-stab connection to fail is certainly there for the reasons he cited, I've just not witnessed (yet) this failure as a primary problem relative to the other deficiencies of crappy devices.
As far as the stab in connectors replacing the wire nut, who knows... but hopefully they won't follow down the path taken by other innovations like polybutylene, FRT plywood, CCA, creosote and asbestos.
Tom
Edited 11/15/2007 3:59 pm ET by TomE
First off, treat the grounds the way you're supposed to -- tie them all together into a tight bundle in the back, before deailing with other wires. When you do this you can generally remove a lot of wire, since the grounds, once tied in place, don't need to be accessed -- you just need pigtails coming forward for any devices.
Thanks folks, some good ideas out there. My question was meant to focus on some general strategies, which some have supplied, rather than on the specifics of this particular device box, which was given just for illustration (although it does exist).Highfigh - I am using the maximum capacity combination that I have found locally, a 4x4x2 1/8 box plus a 1 1/8" mud ring. This combination gives 45.3 cu in. I didn't find any extension for a 4 11/16x4 11/16 box that gave larger capacity with the ability to install two outlets.Woodturner9 - I exaggerated the fill slightly. Twelve 12 gauge conductors and 2 devices (with no internal clamps) should give me 38.25 cu in of fill and, as in the above paragraph, I have a little over 45 cu in, for a "spare space" of about 7 cu in. Still, it is hard to get all the wires in without really shoving. I have filled boxes to a similar capacity but was using conduit with stranded wire and things went in neatly. With 12 gauge solid wires coming in from various directions and a rats nest of ground wires, it gets a bit more difficult to get things knitted together neatly.Michaelindc - I have two GFCIs in the box.edlee - wrapping seems to work pretty well much of the time, but there is still that rats nest of ground wires coming from all different directions complicating things.DaveRicheson - I cut everything to about 6.5" with at least 3" sticking out of the box when I pulled the wires. Maybe I will try leaving some of them longer and try your technique.PM, IIRC, the NEC rule is to have a minimum of 6" into the box with at least 3" extending beyond the box. I guess this is what you indicate, although I am not sure on which is the "entrance" (I guess you mean where the wire enters the box, not where I do...). I will take a look at the connectors. Hopefully things will not come down to requiring the "third hand". So far I have just been shoving the wires with my screwdrive - the handle end, not the sharp end...DanH - I have generally done this, but still it can be a challenge to get all those pesky grounds snaked around so that the conductors can be circled around the back of the box. I have always tied all the grounds together but I haven't really found where in the NEC this is actually required. A metal box has to be tied to ground and each device has to be tied to ground and of course each circuit has to have continuity of its ground wires, but I don't understand when two different circuits come through a box, why the two circuits have to be tied together. In one metal box in my kitchen, there are two 12 gauge appliance circuits and one 14 gauge lighting circuit. Why does the lighting circuit ground in this box have to be tied to the appliance circuits rather than having all 12 gauge grounds, for the two devices and the box, tied together and all the 14 gauge grounds tied in a separate bundle. It would have made things simpler for winding the grounds in the back of the box if I had kept them separate.
Well, one reason for doing it is that it's simpler.
Generally, for rough in inspection the inspector wants to see all the grounds tied and neatly pushed to the back, with the other wires coiled neatly in the box.
If your view never changes you're following the wrong leader
Preface: I'm not an electrician.
The biggest tip I have found is to use more wire, not less. Amateurs seem to cut the wires too short, making them stiff and un-foldable. I pre-fold the Romex (I’m assuming you are using Romex or a similar NM cable) in an accordion fashion. The wire will be against the back of the box and bent down, up, down to form the folds. Then clip the ends off at the same length, un-stretch the accordion, strip the outer jacket and individual wires and connect.
I apologize if the above is simplistic; it is just a small tip that has helped me quite a bit over the years.