Pullbox Size Calculator
Choose a straight or angle pull, enter the largest raceway trade size and the sum of the other raceways on the same wall. The calculator applies the 8 × and 6 × rules of NEC 314.28 and gives the minimum box size.
- Box length
- Distance to the opposite wall
- Raceway spacing
Use trade sizes in inches, such as 2 for 2 in conduit.
Pull boxes for conductors 4 AWG and larger have minimum sizes. For a straight pull, the box is at least 8 times the largest raceway. With 2 in conduit that is 16 in. For an angle pull, the distance to the opposite wall is 6 times the largest plus the other raceways in that row, such as 6 × 2 + 1.5 = 13.5 in.
Pull box size chart
NEC 314.28. Search for a size.
| Largest raceway (in) | Straight pull (in) | Angle pull, single (in) |
|---|---|---|
| 0.75 | 6 | 4.5 |
| 1 | 8 | 6 |
| 1.25 | 10 | 7.5 |
| 1.5 | 12 | 9 |
| 2 | 16 | 12 |
| 2.5 | 20 | 15 |
| 3 | 24 | 18 |
| 3.5 | 28 | 21 |
| 4 | 32 | 24 |
Inches.
Raceway and box
Straight pull. Slide the raceway size.
The box grows with the largest raceway.
How to size a pull box
Raceway to box. Step through it.
Pull type
Straight or angle.
Check each wall and each row of raceways for an angle pull, and use the largest.
Straight, angle or U pull
Pull types. Compare them.
Through.
Corner.
Same wall.
A U pull enters and leaves on the same wall and uses the angle rule.
Before you order
Pull box checks. Tick each item.
Tick each item as you go.
Boxes over 100 cubic inches holding conductors 4 AWG and larger follow these rules.
What you get
Pull box sizing. Each tile explains one result.
Minimum.
8 × or 6 ×.
To order.
Raceways.
NEC 314.28.
Raceways holding the same conductor must also be at least 6 × the largest raceway apart.
Frequently Asked Questions
No question matches that search.
How do I size a pull box?
For a straight pull, eight times the largest raceway. For an angle pull, six times the largest plus the other raceways in the row.
What size pull box for two inch conduit?
At least sixteen inches long for a straight pull.
What NEC section covers pull boxes?
Section three fourteen point twenty-eight.
Do the rules apply to small wires?
They apply to conductors of four AWG and larger.
What is a U pull?
A pull where the conductors enter and leave on the same wall.
How far apart should raceways be?
Raceways holding the same conductor at least six times the largest raceway apart.
Can the inspector require a bigger box?
Yes. The local authority has the final say.
Room to pull
Size the box by the rules and the cable pulls without damage, and the inspection goes smoothly.
More size calculators
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