OK I am adding an attic junction box and 1 new circuit which involves messing around with two 1/2" EMT conduits.
I have pulled out the existing #12 solid conductors and plan on using all new stranded conductors which are easier to pull.
Between the two 1/2" EMT conduits I need to feed five (6) circuits - all for standard receptacles and lighting purposes. I will be using tandem breakers and sharing the neutral conductors between circuits on opposite legs.
So circuits 1, 2, 3, 4, 5, 6 that would be six hot conductors. circuits 1, 2 will have a common neutral, 3 and 4 one neutral, and 5 and 6 one neutral. No need for ground conductors for EMT. Altogether I will have six hot and three neutral conductors between two 1/2" EMT conduits going to the same attic junction box. I think the only way I can do this is to put 3 conductors in one (circuits 1 & 2) and 6 conductors in the other (circuits 3, 4, 5, 6) right?
Which lead to the question, is six #12 stranded THHN conductors too much for a 1/2" EMT? The box fill chart says I can put in 9 #12s but that's before derating kicks in. The way I am reading it, if I put four circuits (six conductors) in one 1/2" EMT, and the code says that 4 to 6 current carrying conductors would need to derate by 20%, which means in my case my circuits 3, 4, 5, 6 canNOT be 20A but 15A breakers correct?
IF the above is correct, then would it be better for me to divide up the six circuits EQUALLY between the two 1/2" conduits? In other words, put circuits 1, 2, 3 in one conduit (circuit 1 has it's own neutral, circuits 2,3 MWBC), and circuits 4, 5, 6 in the other conduit (circuit 4 has it's own neutral, circuits 5, 6 MWBC). The total number of conductors between the two conduits is actually more (10 total instead of 9) but in each conduit will be 3 hot and 2 neutral. If I do it this way, do I still need to worry abiut derating? Do the neutral conductors count as "current carry conductors"?
I have pulled out the existing #12 solid conductors and plan on using all new stranded conductors which are easier to pull.
Between the two 1/2" EMT conduits I need to feed five (6) circuits - all for standard receptacles and lighting purposes. I will be using tandem breakers and sharing the neutral conductors between circuits on opposite legs.
So circuits 1, 2, 3, 4, 5, 6 that would be six hot conductors. circuits 1, 2 will have a common neutral, 3 and 4 one neutral, and 5 and 6 one neutral. No need for ground conductors for EMT. Altogether I will have six hot and three neutral conductors between two 1/2" EMT conduits going to the same attic junction box. I think the only way I can do this is to put 3 conductors in one (circuits 1 & 2) and 6 conductors in the other (circuits 3, 4, 5, 6) right?
Which lead to the question, is six #12 stranded THHN conductors too much for a 1/2" EMT? The box fill chart says I can put in 9 #12s but that's before derating kicks in. The way I am reading it, if I put four circuits (six conductors) in one 1/2" EMT, and the code says that 4 to 6 current carrying conductors would need to derate by 20%, which means in my case my circuits 3, 4, 5, 6 canNOT be 20A but 15A breakers correct?
IF the above is correct, then would it be better for me to divide up the six circuits EQUALLY between the two 1/2" conduits? In other words, put circuits 1, 2, 3 in one conduit (circuit 1 has it's own neutral, circuits 2,3 MWBC), and circuits 4, 5, 6 in the other conduit (circuit 4 has it's own neutral, circuits 5, 6 MWBC). The total number of conductors between the two conduits is actually more (10 total instead of 9) but in each conduit will be 3 hot and 2 neutral. If I do it this way, do I still need to worry abiut derating? Do the neutral conductors count as "current carry conductors"?
