I am trying to install a 20A circuit (#12AWG wire) in about 25ft of wiremold with 4 duplex outlets. I am trying to use stranded THHN but have a concern about terminating the stranded wire in the outlets. I have also tried to use solid wire, but, WOW, try to form 5 #12AWG solid conductors in a wire mold box! I can't do it... so its back to the stranded... (no room for solid to stranded splice)

There does not seem to be room (depth) to use fork terminals. Even if there was, the recessed side screws won't allow it. Can I use some kind of brass or copper washer to eliminate the recess?

Using the stranded wire requires a rear insertion outlet. I am concerned that this connection will deform the wire so that I will have issues if I ever have to replace the outlet. Because of the limited room in the box I cannot use any "extra" wire for future cleanup.

Any ideas...

 

buy deeper wiremold boxes. Off the top of my head I think the number is 5745. If you backstab stranded wire into an outlet you must buy the good ones that rely on a clamping action to terminate the wire rather than the cheap spring connection you'll get with the 45 cent outlets

 

With stranded I strip a little more insulation than normal, roughly 1". I strip back on the insulation but not all the way off. I then grasp the end of the wire with my linemans and twist until it becomes pretty solid. I then loop the end of the wire and install under the device screw and trim off the excess. It works well.
I have done this for years as do most of the journeymen I know.
I don't care for Sta-Cons with devices.

 

I am using a somewhat expensive Hubbell outlet ($12.00) which does use the clamp. Not the cheap strip and poke type.

The wiremold box I am using is about 1-1/2" deep. The really deep ones (~2") stick too far off the wall for my taste and am not sure it will help that much. The solid wire is just too unruley!

Will solder "tinning" the wire after it is formed hurt anything? Will it help? Putting it under the screw head scares me by you can't beat experience. I will try on one in the morning.

 

If you are using a good back wire receptacle just use the back wire clamp. They work better on stranded than solid anyway.

Don't put the wire under the screw. It goes under the clamp. Just give the wires a twist to firm them up.

 

No, use the method speedy petey discribed. Tinning those wires isn't the best way to go.

 

Your box is too small. You exceded the wire fill calcs. It is even worse if those five wires didn't include a ground wire. That adds another 2.25 cu in.
5 #12 wire + a receptacle equals 7 devices.
7x2.25 is 15.75 cu in required
A 1.5 box is only 13.5 cu in.

 

The wiremold box I am using has a volume of ~20 cubic inches. By my calculations the required volume needs to be what was already stated ... 15.75 cubic inches. Therefore I think the box size is good. Granted the deeper box would make life simplier but that would more than double the cost of the boxes which would add up quick on this job.

I guess I'm just being paranoid about the stranded wire. My concern is that there wouldn't be much wire to re-strip (if needed) when the outlet needs to be replaced. I know that probably won't be for 10-20yrs and even then just pull new wire in the wiremold.

Am I just over analyzing this?

Thanks for all the comments!

 

Probably. I wouldn't worry about a heavy duty Hubbell outlet wearing out in your lifetime unless you are in a pretty rough industrial environment...

 

You must leave the wire long enough so that at least 6 inches sticks out of the box.

If your box is marked 20 cu in then you are good for box fill.

 

I don't understand why you're having a problem with (5) solid #12 conductors in a 20 cu.in. box. You just need to accordian them into the box a liitle better.

If you do use stranded wire on terminal screws, twist them tight as mentioned before, but make sure you twist them counter-clockwise (as seen from facing the tip). That will help in keeping the strands from walking out from under the screw as you tighten it. Twist clock-wise when using a wire nut.