zmccartney
New member
Hi all (1/5/06),
This is my first post, and I am an ME not an EE, so please bear with me if my question seems elementary. I know any response is not a formal NEC interpretation; I am just trying to get some constructive feed back and consensus since I am still learning this stuff.
Basically I need help with determining the allowable number of conductors in a box based on the gauge wire and box volume. This is what I have been told so far; please correct me if it is incorrect. Assuming a 3 conductor wire I am assuming that each "hot" wire counts as an individual conductor (either coming in and/or going out), that the ground wires can be all connected together and counted as one conductor, and that a device, such as a standard 120V outlet or switch counts as two conductors each. So if I just had a 3 conductor wire going to a standard light switch, I would have 5 conductors in that box and would need to size it according to Table 314.16A of 2002-NEC; correct? The other assumption I am making is that if I want a 120V service line, the smallest gauge I am allowed is 14 AWG. Now for the payoff question; what about a 3x2x1.5 box? According to the table it is 7.5in3 and can only hold 3-conductors assuming 14 AWG, which is not enough room assuming my assumptions above, yet I have seen these boxes advertised to "house wiring devices such as switches or receptacles." So does anyone know which one is right? With this in mind, as for my specific application, would it be acceptable to use a 3x2x2 steel box, 14 AWG, 2 or 3 conductor wire to go into the box with a receptacle, then out of the box to any box? Any help and enlightenment would be greatly appreciated.
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Hi again (1/6/06),
The moderator suggested that I post my personal contact with him as further explaination of my question. He asked for the purpose of my questions, and I replied with...
Fair enough...I (as an untrained person) am not trying to install any electrical device or instruct any other untrained person to perform any electrical installations either. My questions stem from the fact that my company has used electrical boxes as an integral part of some of our construction products. Now all these boxes were installed and wired by trained professionals. The problem is that upon inspection, some inspectors have approved it and some have rejected it saying it was too small for the application. What is unique about our product is that an electrical box can fit into it, but there are some size limitations. I am trying to accurately determine conductor fill, which dictates the box volume, so that I can either modify our product to an appropriately sized box or just recommend a different dimensioned box with the same volume to fit our product, based on Table 314.16 of the 2002-NEC (mind you, all installation and wiring would be done by a trained professional). I posted my questions because I was getting different answers from different people, and what I was reading out of the NEC wasn't jiving with what I was being told...which is rather frustrating. So to ensure passing our electrical inspections, I am trying to understand how the inspector is making his determination (which I am assuming is based in the NEC), so that I can redesign our product if necessary for future use.
Thanks,
Zach
[ January 06, 2006, 09:19 AM: Message edited by: zmccartney ]
This is my first post, and I am an ME not an EE, so please bear with me if my question seems elementary. I know any response is not a formal NEC interpretation; I am just trying to get some constructive feed back and consensus since I am still learning this stuff.
Basically I need help with determining the allowable number of conductors in a box based on the gauge wire and box volume. This is what I have been told so far; please correct me if it is incorrect. Assuming a 3 conductor wire I am assuming that each "hot" wire counts as an individual conductor (either coming in and/or going out), that the ground wires can be all connected together and counted as one conductor, and that a device, such as a standard 120V outlet or switch counts as two conductors each. So if I just had a 3 conductor wire going to a standard light switch, I would have 5 conductors in that box and would need to size it according to Table 314.16A of 2002-NEC; correct? The other assumption I am making is that if I want a 120V service line, the smallest gauge I am allowed is 14 AWG. Now for the payoff question; what about a 3x2x1.5 box? According to the table it is 7.5in3 and can only hold 3-conductors assuming 14 AWG, which is not enough room assuming my assumptions above, yet I have seen these boxes advertised to "house wiring devices such as switches or receptacles." So does anyone know which one is right? With this in mind, as for my specific application, would it be acceptable to use a 3x2x2 steel box, 14 AWG, 2 or 3 conductor wire to go into the box with a receptacle, then out of the box to any box? Any help and enlightenment would be greatly appreciated.
------------------------------------------------
Hi again (1/6/06),
The moderator suggested that I post my personal contact with him as further explaination of my question. He asked for the purpose of my questions, and I replied with...
Fair enough...I (as an untrained person) am not trying to install any electrical device or instruct any other untrained person to perform any electrical installations either. My questions stem from the fact that my company has used electrical boxes as an integral part of some of our construction products. Now all these boxes were installed and wired by trained professionals. The problem is that upon inspection, some inspectors have approved it and some have rejected it saying it was too small for the application. What is unique about our product is that an electrical box can fit into it, but there are some size limitations. I am trying to accurately determine conductor fill, which dictates the box volume, so that I can either modify our product to an appropriately sized box or just recommend a different dimensioned box with the same volume to fit our product, based on Table 314.16 of the 2002-NEC (mind you, all installation and wiring would be done by a trained professional). I posted my questions because I was getting different answers from different people, and what I was reading out of the NEC wasn't jiving with what I was being told...which is rather frustrating. So to ensure passing our electrical inspections, I am trying to understand how the inspector is making his determination (which I am assuming is based in the NEC), so that I can redesign our product if necessary for future use.
Thanks,
Zach
[ January 06, 2006, 09:19 AM: Message edited by: zmccartney ]
:roll: