Box fill requirements NEC vs CEC

[Kevin W Holland]

Good morning all.
Question for Canadian electricians: Are the box fill requirements in the CEC different than in the NEC to the extent that a 2-1/2 deep metal gem box stamped with "12.0 cu in" inside the box is allowed to have (3) #12-2 MC cables enter the box and also, upon trim, will have a device (receptacle) also installed within the box? A client who has relocated from Toronto, CA to here in SW Florida claims that they allow this configuration. ? Of course the electrical inspection failed miserably and all the 1-gang gem boxes had to be changed out. To which the GC stated "well, I guess some things we can do in Canada we cannot do here". Can I get some clarification on this from Canadian electricians?
Thanks in advance.

 

[CoolWill]

I'm no Canadian, but I have studied a bit of the CEC, and the way I understand it, you can get more wires in less volume, but wire nuts count as well. Every pair of wires connected together counts off 1 conductor. All grounds count individually. And the device counts as two.

I looked it up, and each #12 consumes about 1.75 in³, so three 12-2 MC cables would be 9 conductors and a device is 17.75 in³, then at least 3 pairs of wires have to be connected, so that is another 5.25 in³, bring the total up to 24.5 in³.

I could be off a bit, but I don't believe the CEC allows three 12-2s and a device in a 12 in³ box.

 

[curt swartz]

Obviously the box fill does not meet NEC or CEC requirements. I can't imagine trying to splice (3) 12/2 cables in such a small box let alone try and get a device into it.

For me (3) 12/2 MC cables would be getting a 4SQ deep with single gang ring. Standard 4SQ meets NEC but minimal additional cost but makes life much easier.

 

[letgomywago]

Here's the Canadian table they add for wirenuts and devices separately also. Looks like even there he's off.

 

[Kevin W Holland]

I'm no Canadian, but I have studied a bit of the CEC, and the way I understand it, you can get more wires in less volume, but wire nuts count as well. Every pair of wires connected together counts off 1 conductor. All grounds count individually. And the device counts as two.

I looked it up, and each #12 consumes about 1.75 in³, so three 12-2 MC cables would be 9 conductors and a device is 17.75 in³, then at least 3 pairs of wires have to be connected, so that is another 5.25 in³, bring the total up to 24.5 in³.

I could be off a bit, but I don't believe the CEC allows three 12-2s and a device in a 12 in³ box.

Thanks for your opinion. Take care.

 

[Kevin W Holland]

Obviously the box fill does not meet NEC or CEC requirements. I can't imagine trying to splice (3) 12/2 cables in such a small box let alone try and get a device into it.

For me (3) 12/2 MC cables would be getting a 4SQ deep with single gang ring. Standard 4SQ meets NEC but minimal additional cost but makes life much easier.

Thanks for your opinion/input.

 

[Eddy_Current]

No Canadian code does not allow 3 x 12/2’s in that box.
As you can see on table 23 that was posted, it shows a max of 7 x 12 awg conductors for a 3x2x2 1/2 device box with a 12.5 volume.

Canadian code counts all insulated conductors. (12-3034)
A bare ground would not be counted but an insulated one would be. A device counts as 2 conductors and every two wirenuts count as one conductor.

With an MC cable, the insulated ground would have to be counted, but even if you used Canadian AC90 with a bare ground, 3 x 12’s would not pass. You got 6 insulated conductors, 2 for the device and another one for two wirenuts. That would equal 9 conductors. Table 23 says 7 max.