Quick conduit fill question

[rust buster]

Can someone verify whether or not I can do this?
Can I run (3) #6 THHN conductors, (3) #10 THHN conductors, and (3) #12 THHN conductors in a 3/4" EMT conduit? I'm getting mixed results on the online calculators I am reading.

Running from my panel in the shop to a two post lift, so it's the lift power, a welder outlet, and a 20A general use outlet.

Thanks in advance.

 

[Stuart in MN]

I've found this calculator to be pretty good: http://www.electrician2.com/calculators/rf_calculator.html It says you'll need a 1" EMT conduit minimum. However, it doesn't take into account derating the wire, so if you have more than three currrent carrying conductors you need to consider that as well.

 

[rust buster]

Thanks for the quick response Stuart. I can't get that link to work, but it might be my computer.

 

[Stuart in MN]

That's odd, I'll try posting the link again: http://www.electrician2.com/calculators/rf_calculator.html

edit: fixed the link.

A few other things to consider. I'm assuming the #6 wires are for the welder circuit, if so you can probably downsize the ground wire to a #10. Secondly, depending on what you're doing at the far end (is all this going into a junction box, then splitting off to each circuit?) you can share a single ground wire. Third, if the EMT is a continuous metallic path you may be able to use it as the ground connection instead of running separate wires. However, there may be local restrictions on this method; also some prefer not using the conduit as the ground connection as there's the possibility of a loose conduit fitting in the future.

 

[rust buster]

Now it works! No idea what the issue was.
Thanks!

 

[FarmerPete]

You're going to have to derate with that many conductors. From my experience working with #6 in a 3/4 EMT, I would recommend going to 1".

 

[rust buster]

Yeah, based on all replies, I think I am going to run two different runs of 3/4" conduit. Keep the #6 in one run and then the #12 and #10 in another. I already have plenty of the 3/4" and this will allow me to keep the wire length down since I can run them in a direct route to their end location.

 

[rockwithjason]

that might be better for you .

 

[ddawg16]

If the run is of any distance, I would up size to 1". Especially if you have 2-3 90's in there. It just makes life a whole lot easier and the cost difference is minimal.

 

[rockwithjason]

wise also