I need help with this calculation

[OSC16]

I am trying to figure out what size EMT must I go with to fit 14 number 12 AWG THHN?

So what size EMT should I go with? I have done the math and I have come up with 3/4. Is this right? Please let me know.

 

[iwire]

Sure

But when your done you will be lucky if the derated ampacity of the conductors is even 15 amps.

 

[Dennis Alwon]

3/4" emt is correct however you must derate based on Table 310.15(B)(2)(a)

14 wires means you must derate 50%

 

[nizak]

If space allows, would probably just be easier to run 2 conduits. BTW, I would assume you are talking about a long run and not just a short nipple between 2 points(i.e. a panel and a trough for instance).

 

[LarryFine]

3/4" emt is correct however you must derate based on Table 310.15(B)(2)(a)

14 wires means you must derate 50%

In other words, if you need the 15a per circuit, you'd have to use #12 (starts @ 30a), then recalculate the conduit for 14 #12's.

 

[don_resqcapt19]

I am trying to figure out what size EMT must I go with to fit 14 number 12 AWG THHN?

So what size EMT should I go with? I have done the math and I have come up with 3/4. Is this right? Please let me know.

Why do the math? There are tables in Annex C with this all worked out for cases like this where all of the conductors are of the same size and type.