Online Calculators and Tables to Help You Determine Proper Wire Size
These tables list the maximum distance between conduit supports for rigid metallic and non-metallic conduit.
Supports for Rigid Metallic Conduit
| Conduit Size | Distance Between Supports |
|---|---|
| ½" - ¾" | 10 Feet |
| 1" | 12 Feet |
| 1¼" - 1½" | 14 Feet |
| 2" - 2½" | 16 Feet |
| 3" and larger | 20 Feet |
Supports for Rigid Non-Metallic Conduit
| Conduit Size | Distance Between Supports |
|---|---|
| ½" - 1" | 3 Feet |
| 1¼" - 2" | 5 Feet |
| 2½" - 3" | 6 Feet |
| 2½" - 5" | 7 Feet |
| 6" and larger | 8 Feet |
For SI Units: 1 foot = 0.3048 meters
View wire size charts from the list below.
Maximum Allowable Ampacities for Conductors in Raceway, Cable or Earth (30°C)
Maximum Allowable Ampacities for Conductors in Free Air (30°C)
Maximum Allowable Ampacities for Conductors in Raceway, Cable or Earth (40°C)
Maximum Allowable Ampacities for Conductors in Free Air (40°C)
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