Multiply the area of one wire by the number of wires you plan to pull.
PVC conduit (Schedule 40 & 80) has different IDs due to thicker walls. Schedule 80 PVC has smaller ID than Schedule 40 of the same trade size. conduit sizes
When choosing a conduit size, consider the following factors: Multiply the area of one wire by the
| Conduit Type | Wall Thickness | ID relative to trade size | Typical Sizes Available | |--------------|----------------|---------------------------|--------------------------| | EMT (thinwall) | Thinnest | Largest ID | 1/2” to 4” | | RMC (rigid) | Thick | Smallest ID (for same trade size) | 1/2” to 6”+ | | IMC (intermediate) | Medium | ID between RMC and EMT | 1/2” to 4” | | PVC Sch 40 | Medium | Similar to EMT | 1/2” to 24” | | PVC Sch 80 | Thickest | Smallest ID (for plastic) | 1/2” to 24” | | ENT (smurf tube) | Thin | Large ID | 1/2” to 2” | When choosing a conduit size, consider the following
For metric (ISO) conduit sizes (used outside North America), trade sizes are in mm: 16, 20, 25, 32, 40, 50, 63, etc., with different fill rules per IEC 61386.