Conduit Fill Calculations

Conduit Minimum Area

40% Fill Rate for 2 strings/4 conductors in a conduit

PVC Schedule 40 Conduit

How Many PV Wires can you fit in each Conduit?

You will use Schedule 40 PVC electrical conduit when below ground.

https://www.cantexinc.com/Portals/0/CANTEX-Schedule-40-and-80-Conduit-Sell-Sheet.pdf

PVC Schedule 80 Conduit

You will need Schedule 80 Conduit when outside and above ground.

Liquidtight Flexible Metal Conduit

https://assets.southwire.com/ImConvServlet/imconv/8c11f9ef2ee16212e21baad40104faf1c527ccd0/origin?assetDescr=Titan-2-Type-UL-Liquidtight-Flexible-Metal-Conduit

3/4: https://amzn.to/47RxXe8

1”: https://amzn.to/3WW7mHO

Will need to make sure it isn’t in a location that is likely to be crushed by a vehicle. Your Electrical inspector may not permit LFMC if it is in a location where it may be damaged.

Metal Conduit (EMT)

EMT will need to be used where it enters your structure.

Burial Depth

PVC Schedule 40: Look at the 3rd column. Nonmetallic Raceways. Bury under a minimum of 18” of dirt.

Direct Burial No Conduit: First Column, Minimum of 24” of dirt.

References For Conduit Fill

Sample Calculations

National Electric Code Wire Introduction: https://www.youtube.com/watch?v=RMpglgQgdDA

Calculate Diameter of Conduit for 4x10AWG, XLPE, PV Wire.

Conduit Diameter = (Fill Capacity 4 wires

10AWG PV Wire XLPE insulation OD 0.230” Area = .0415sqin

4x.0415"=0.167sqin

Chapter 9 Table 1 (Cross Section ofConduit andTubing for Conductors): Qty of Wires 4 = 40%

0.167/.4=.415sqin

Internal Diameters: https://www.cantexinc.com/Portals/0/CANTEX-Schedule-40-and-80-Conduit-Sell-Sheet.pdf

.75” pipe: .698”/2=0.349”, 0.349^2*3.14=.382 sqin

Too small needed at least .415sqin

.91/2=0.455”, 0.455^2*3.14 = 0.65sqin larger than 0.415 so the 1” pipe works.

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