multiple multiconductor tray cables in RMC help

[TexMasterElectrician]

I'm looking for some direction on conduit fill when using multiple multiconductor tray cables in a RMC and PVC conduit. For example coming out of a box through the nipple into the cable tray, then going underground in PVC but with Rigid 90's and rigid above ground. Back to cable tray and then finally 1-3 tray cables in RMC to feed a skid with several motors on it. Also for some insight this is an industrial application outdoors in an oilfield facility. I have the overall diameter of wire from manufacturer (.294) for 16 awg single pair, and using chapter 9 table 4, 1.5" RMC is .829 at 40%. This is where I getting stuck. Or am I just not even in the same ballpark with the answer?

 

[wwhitney]

If the diameter (largest dimension) of the cable is 0.294", then the circular area of the cable is pi/4 * 0.294² = .0678 in². So if you allowed fill is 0.829 in², you can fit up to 12 cables. (0.829 / 0.0678, rounded down).

Cheers, Wayne

 

[TexMasterElectrician]

If the diameter (largest dimension) of the cable is 0.294", then the circular area of the cable is pi/4 * 0.294² = .0678 in². So if you allowed fill is 0.829 in², you can fit up to 12 cables. (0.829 / 0.0678, rounded down).

Cheers, Wayne

I knew I was missing the last piece of the puzzle. Thank you so much. Also I'm assuming that formula should work if I plug in different numbers according to the specs?

 

[wwhitney]

I knew I was missing the last piece of the puzzle. Thank you so much. Also I'm assuming that formula should work if I plug in different numbers according to the specs?

Yes, the area of a circle will always be "pi * diameter squared /4."

For further details and important clarifications, see Chapter 9 Table 1 and all its notes.

Cheers, Wayne