Outlets and gem boxes


Happy New Year Audiogoners!

I will be installing a new dedicated 20amp circuit for my 2 channel system using 10awg cryo treated cable connected to a Furutech GTX D outlet with aluminum wall plate and cover from same manufacturer to shield from RF/EMI. That said, do I need to consider some way of shielding the gem box in the wall that the outlet is fastened to. Any thoughts on this. Thanks for your support.
audiofool1

If the branch circuit wiring is NM-B cable, (Romex is a Trade Name manufacture of NM-B sheathed cable), then the outlet box really will not be an EMI/RFI issue, jmho.

If NM-B cable is used I prefer a plastic box over a steel ferrous box.

If an old work box, (Gem box, cut in box), must be used then, because of the duplex receptacle you will be using I am not sure the plastic support ears and back supporting tabs will hold up cut into 1/2" or even 5/8" drywall. It might if you cut the hole for the box as tight as possible. (You will not want the box to be able to walk, move, in the drywall when plugging in and unplugging a plug from a receptacle of the duplex outlet). Other wise use a steel cut in box with ears. Even if you use a steel cut in box keep the cut hole as tight as possible, for the same reason as above.

As for pushing the plug into the receptacle the aluminum duplex cover plate will help in reducing the pressure exerted on the cut in box supporting ears whether plastic or steel.

If the wire is #10-2 with ground NM-B cable use a deep box. #10 solid core can be a bare to work with. You need all the room you can get. I also recommend your electrician curl the wire around the side terminal screws instead of using the screw down terminal plate to support the hot and neutral wires.

Jim


Jim thank you so much for your advise. Much appreciated. I am using NM-B #10-2 as you mentioned. The electrician said he will have to use a larger box because of the wings on the Furutech outlet are wider than a standard duplex outlet. I will make sure that he uses the screws to fasten the wires to the outlet. Happy New Year!
Is the wall the outlet will be installed in finished on both sides? Drywall on the new outlet side? Wood studs?
Jim
Yes. the interior wall is sheet rock and the exterior wall is brick. 2x4 construction.

Forgo to mention wood studs.

Outside wall. Cold winter climate?

Has the electrician said what type of bigger box he is planning on using? Will the hole in the wall for the new rough-in box need to be bigger than the duplex cover plate and therefore need to be patched and repainted?

By chance do you have the Furutech GTX D outlet? If so measure the total width 'wing' to 'wing'. What does it measure?
Yes. Outside wall cold climate. He did not say which box he would use. The  sheet rock should be able outlet measures 1.75" wide at the wings. I think the sheet rock should be able to be cut close to the box and not require patching. I think the cover plate will cover the opening in the wall completely with no gaps.

1 - 3/4" wide. That’s only 1/16" more than a GFI duplex receptacle. A Gem box, switch box , with ears would be a tight fit with the dry wall supports added on each side of the box. A GFI duplex receptacle just fits with maybe a 1/32" to spare.
3-1/2" deep switch box with ears.
https://www.homedepot.com/p/RACO-3-1-2-in-Deep-Gangable-Switch-Box-with-Armored-Cable-Metal-Clad-Fle...
Drywall supports
https://www.homedepot.com/p/RACO-Old-Work-Switch-Box-Supports-8977/100547662

You might be a little strong on your 1.75" measurement. Surely Furutech wouldn’t make it any wider than a GFI outlet.
>>
In case the electrician wants to install a steel 4" X 4" box with a 1 gang 5/8" raised device cover he would need to cut a hole at least the size of the 4" X 4" box. That would require patching and painting. And if the wall has an orange peel texture you would also have to deal with that too. Nice electrical job though. Lots of room for the electrician to wire the outlet. Not so good for you though....

4" X 4" X 2 1/8 steel box
https://www.homedepot.com/p/RACO-4-in-Square-Welded-Box-2-1-8-Deep-with-1-2-3-4-in-TKO-s-25-Pack-823...

1 gang 5/8" raised device cover.
https://images.homedepot-static.com/productImages/dfbd6366-dd8c-4eb5-aad8-529f9f1dbb26/svn/raco-cove...

>>>

Here are a couple of options the electrician may be already be thinking of. If not you might mention them to him and see what he thinks.

1) A 1 gang 3-1/2" deep steel masonry box.
https://www.homedepot.com/p/RACO-Single-Gang-Masonry-Box-3-1-2-in-Deep-with-1-2-and-3-4-in-Concentri...

- The electrician would have to cut the hole fairly tight. Especially the top and bottom of the box. You want to make sure the duplex cover plate covers all the way around the box.
- For mounting the box it would need to be cut-in next to a stud in the wall.
- He would need to drill four 3/16 holes on one side of the box to support the box to the stud.
- Keep the holes near the top and bottom of the side as much as possible. (That way they will not interfere with the receptacle in any way.)
- Front 2 holes about 5/8" from the front edge of the side.
- Next 2 holes about an 1-1/2" back from the front edge of the box.
- Fasten box to stud with four 1-1/4" drywall screws.
A 6" Phillips bit works great chucked in a battery drill for driving the screws. A must for the back 2 screws. (Screws will be installed at an angle into the stud.)

Note all of the above options are steel boxes. In an outside wall a steel box will conduct the cold air inside the stud space even though the wall is insulated. If it gets really cold the steel box may get frost on the inside of the box if the air inside is warmer than the air on the outside of the box.

Next option. Best, JMHO.....

2) A deep 1 gang plastic switch box, at least 20 Cubic Inch. (The deeper the better for the #10 solid wire.)
Example of. 22.5 Cubic Inch. (Buy a good one.)
https://www.menards.com/main/electrical/rough-electrical/junction-boxes/legrand-reg-slater-reg1-gang...
- The electrician would need to cut off the existing plastic nail supports on the top and the bottom of the box.
- Install the box in the same manner as the masonry box.
Again, cut the hole for the box fairly tight. Especially top and bottom.
- Drill holes near the top and bottom side of the box.

Jim





EDIT:
Note all of the above options are steel boxes. In an outside wall a steel box will conduct the cold air inside the stud space even though the wall is insulated. If it gets really cold the steel box may get frost on the inside of the box if the air inside is warmer than the air on the outside of the box.

If it gets really cold the steel box may get frost on the inside of the box if the air inside is warmer than the air on the outside of the box.
I should have said.
  If it gets really cold the steel box may have condensation form on the inside of the box and possible frost if the air inside the box is warmer than the air on the outside of the box.

Jim
EDIT:

Next option. Best, JMHO.....

2) A deep 1 gang plastic switch box, at least 20 Cubic Inch. (The deeper the better for the #10 solid wire.)
Example of. 22.5 Cubic Inch. (Buy a good one.)
https://www.menards.com/main/electrical/rough-electrical/junction-boxes/legrand-reg-slater-reg1-gang...
- The electrician would need to cut off the existing plastic nail supports on the top and the bottom of the box.
- Install the box in the same manner as the masonry box.
Again, cut the hole for the box fairly tight. Especially top and bottom.
- Drill holes near the top and bottom side of the box.

- The electrician would need to cut off the existing plastic nail supports on the top and the bottom of the box.

Actually all he needs to do is remove the 2 nails. There is no need to cut off the nail supports.
- He will strip the outer sheath from the NM-B cable and install the 3 wires through one of the entry holes provided in the box.
- He will then install the box at an angle completely through the cut hole in the drywall and then pull it back forward through the hole lining up the front of the box flush with the finish drywall surface.
- Support the box to the stud with 4 drywall screws through the 4 pre-drilled holes in the box.

Jim