Two-sided, or through-wall electrical box


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Old 07-28-08, 07:59 AM
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Two-sided, or through-wall electrical box

Hello,

Is there any such thing as a two-side electrical box?

One that I can wire outlets/switches on both sides of a wall with one box?

Regards,
Clarence
 
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Old 07-28-08, 12:11 PM
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I doubt it. There's no demand, or at least so little demand as to not be worth producing and distributing it. Just move one of the boxes a little so that they aren't exactly back to back. It's done every day.

Besides, even if there was one, walls aren't all the same thickness due to differences in the width of a 2x4 (yes, not all 2x4s are exactly the same thickness) and differences in drywall thickness.

Furthermore, such a box would almost certainly be overcrowded as you need more than half the thickness of a wall to have a reasonable amount of room.
 
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Old 07-28-08, 04:38 PM
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There is one on market however.,,

It is pretty rare now to see it for new installment due the codes { both electrical and building codes come up with that}

The most common methold is get one box on one side of wall then other side of the wall move it over few inches or other stud cavity.

Merci,Marc
 
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Old 07-28-08, 07:09 PM
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Originally Posted by ClarenceDonath
Hello,

Is there any such thing as a two-side electrical box?

One that I can wire outlets/switches on both sides of a wall with one box?

Regards,
Clarence
They do, but the better choice is just a 4" sq. metal or plastic box with a mudring...
 
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Old 07-29-08, 06:15 AM
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Originally Posted by Chris75
They do, but the better choice is just a 4" sq. metal or plastic box with a mudring...
Thank you all for your input.

I was advised that I could indeed use two metal boxes, 1.5" deep, back-to-back, using a chase nipple to connect the boxes and provide a wire channel. There is sufficient room in each box for what I'll be installing. At Lowes I found they have three different depth sizes of mud rings to adjust for spacing.

It was also pointed out that, per code, this cannot be done if this is a fire rated wall.

Best regards,
Clarence
 
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Old 07-30-08, 08:15 AM
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Clarence, thanks for the information. That's what's great about this forum is that we can all learn something.

For me personally, working in small boxes is way too annoying.
 
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Old 07-30-08, 08:48 AM
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Not very many wires can legally go into a single device box 1.5" deep. They are usually only suitable for the last box on a circuit.

For example, a (3x2x1.5" deep) metal device box cannot even have a 14/2 w/gnd romex and a switch or receptacle since it violates the box fill requirements. However, a (4x2-1/8x1.5" deep) metal box can have the same setup and be legal, but if you're using 12 AWG, you'd again be in violation.

What are you installing (wire and devices), and what size boxes (square, single gang)?
 
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Old 07-31-08, 06:30 AM
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Originally Posted by williswires
Not very many wires can legally go into a single device box 1.5" deep. They are usually only suitable for the last box on a circuit.

For example, a (3x2x1.5" deep) metal device box cannot even have a 14/2 w/gnd romex and a switch or receptacle since it violates the box fill requirements. However, a (4x2-1/8x1.5" deep) metal box can have the same setup and be legal, but if you're using 12 AWG, you'd again be in violation.

What are you installing (wire and devices), and what size boxes (square, single gang)?
Hello Williswires,

This box is http://www.lowes.com/lowes/lkn?actio...196&lpage=none

It is at the end of the run w/ 14/2 w/gnd. One side will contain two 15A receptacles, the other side two light switches.

Regards,
Clarence
 
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Old 07-31-08, 09:29 AM
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You're good then.

That box, a 4" square x 1.5" deep shows to have an internal volume of 20 cu. inches.

You will have to allow for the following (14AWG needs a 2.00 cu in allowance):

A) 14AWG conductors from outside the box = 2 X 2.00 cu. in allowances = 4 cu in.
B) 1 or more grounding conductor = 1 X 2.00 cu in allowance for all = 2 cu in
C) recep. device = 2 allowances for this device X 2.00 cu in. = 4 cu in.
C) switch. device = 2 allowances for this device X 2.00 cu in. = 4 cu in.

You need only 14 cu in.

willis
 
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Old 07-31-08, 11:38 AM
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Originally Posted by williswires
You're good then.

That box, a 4" square x 1.5" deep shows to have an internal volume of 20 cu. inches.

You will have to allow for the following (14AWG needs a 2.00 cu in allowance):

A) 14AWG conductors from outside the box = 2 X 2.00 cu. in allowances = 4 cu in.
B) 1 or more grounding conductor = 1 X 2.00 cu in allowance for all = 2 cu in
C) recep. device = 2 allowances for this device X 2.00 cu in. = 4 cu in.
C) switch. device = 2 allowances for this device X 2.00 cu in. = 4 cu in.

You need only 14 cu in.

willis

Excellent information for everyone. Thank you for taking the time to help me out sir.

Best Regards,
Clarence
 
 

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