In the NEC book page 70-168 paragraph 314.16 (b) (1) conductor fill, it seems that the first line of the paragraph contradicts the last sentence. Can you explain this in lay-mans terms. It sounds like you deduct the conductors that are terminated on the device, therefore donot count these conductors at all. Thankyou, Confused!
Hi, Welcome to Just Answer. My name is XXXXX XXX would be glad to assist.
It means that if a conductor enters the box and doesnt connect to another wire, looped or connect to a device, dont count it
Basically, it is not used for anything.
Sorry, mis read your post
What that is stating, is like you have a pigtail on the wires. Connect the whites together and pigtail to a receptacle for instance
That pigtail neither enters or leaves the box
it is just inside the box
Not considered a conductor for fill requirements.
Sorry for any confusion
The system says you have posted, but I do not see anything.
Sorry 1st time using this. just checked my email found answer was waiting on just answer didnot see any reply. In my class study book it has a picture of two conductors coming into a box and the white and black are both under a screw on a device. But the statement below the picture says; Each conductor originating outside the box and terminating inside the box is rated as one conductor. Two are shown here: therefore a deduction of two conductors must be made. This is from NCCER Level One Corriculum.
Also, to 100% answer my question, when conductors terminate on a screw to a device or wire to a light fixture, they are not considered dead-ends and you do not deduct them back out!
Ok, you stated:In my class study book it has a picture of two conductors coming into a box and the white and black are both under a screw on a device. But the statement below the picture says; Each conductor originating outside the box and terminating inside the box is rated as one conductor.
Yes, each conductor is counted. The picture and statement are the same thing. Each one enters and is used and terminated.
But it also says below that sentence, Two are shown here; therefore two conductors must be deducted.
Each single wire is a conductor. So each one counts towards the total.
A conductor is not a cable.
Ok! so basically what that statement means is that when it says deducted it means for the purpose of the box fill calculations to give total.
Yes, you add up the total of the conductors and subtract them from the cu/in of the box capacity
That is why the say deduct from the total of the box cu/in. It is a little misleading
Receptacle box has 2 cables 14/2 enter a box and terminate----Each black is 2, each white is 2 and both grounds together are 2 The receptacle is 4. Total is 14 cu/in. Deduct that from the box capacity of 18 and you have 4 cu/in leftover.
So, that is accepted
If the box is 12 cu/in, it would fail
I understand, thankyou very much! I have another small question may i ask it?
Sure go for it
If you run a 12/2 wire on a 20 amp breaker, and use a 15amp switch can you use a 14/2 wire for the light leg?
The switch can carry 20 amps on the feed through rating so it is allowed. The 14 wire is not rated for 20 amps
Read the switch ratings and it will say 20 amps through put, just like a 15 amp receptacle
Soif you use 12/2 wire you can't or only because you used a20amp breaker instead of a 15 amp breaker?
once the 12/2 leaves the panel, everything on that circuit MUST be #12 or larger
doesnt matter what breaker is used 15 or 20
It is the wire. Someone in the future may see the 12 and put a 20 amp breaker. Then the 14 burns the house down. They had no idea that someone used a 15 for a special connection
I see. Thankyou very much for your assistance, it's been very enlighting!
You are very welcome. Glad to be of service. If your are satisfied with my assistance to your questions then, please do click the Accept for my time.
Contractor-40 Years in the ElectricalTrade