Table 314.16A (Box fill)

[jeff48356]

In the box fill table, it lists the basic 2-1/2" deep metal switch box as only being able to hold 6 #14 conductors (or 5 #12). How would these even be of any use if that precludes a typical installation of 2 #14 romex cables and a switch (such as for a light)? That in itself would be 7 conductors (4 current carrying, 1 ground, and 2 for the device). Not to mention an additional one if the kind with the internal clamps is used. Am I missing something here?

 

[Dennis Alwon]

They are good for dead end not feed thru. When we have to use metal we use the 3 1/2" deep boxes

 

[jeff48356]

They are good for dead end not feed thru. When we have to use metal we use the 3 1/2" deep boxes

Oh I see. I never noticed this until just now. I hardly ever use metal boxes unless I need to install one within a return-air stud cavity. I guess I need to use 4" square ones with device rings.

 

[jeff48356]

Were the box fill requirements different in the 1960's? Because nearly all the homes in my subdivision have the same size metal nail-on boxes, even with feed-thru outlets, whether #12 or #14 is used. So I never gave it a second thought until now.

 

[infinity]

You use that box with only one cable or you'll need a deeper one.