The following table lists common trade sizes with typical actual IDs and ODs for and Electrical Metallic Tubing (EMT) – two widely used types.
Reserved for main service entrance cables or large-scale industrial distribution. Standard Sizes for Popular Materials conduit sizes
In metric regions (Europe, Asia, etc.), sizes are typically defined in millimeters (mm). Common sizes include: The following table lists common trade sizes with
| Trade Size (inches) | RMC – ID (in) | RMC – OD (in) | EMT – ID (in) | EMT – OD (in) | |---------------------|---------------|---------------|---------------|---------------| | 1/2 | 0.602 | 0.840 | 0.622 | 0.706 | | 3/4 | 0.804 | 1.050 | 0.824 | 0.922 | | 1 | 1.033 | 1.315 | 1.049 | 1.163 | | 1 1/4 | 1.364 | 1.660 | 1.380 | 1.510 | | 1 1/2 | 1.592 | 1.900 | 1.610 | 1.740 | | 2 | 2.067 | 2.375 | 2.067 | 2.197 | | 2 1/2 | 2.469 | 2.875 | 2.469 | 2.875* | | 3 | 3.068 | 3.500 | 3.068 | 3.500* | | 4 | 4.026 | 4.500 | 4.026 | 4.500* | Common sizes include: | Trade Size (inches) |
The most common size for residential branch circuits, like outlets and lights.
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.