Construction

Junction Box Sizing Calculator

Find minimum junction box length for straight pulls (NEC).

Calculated Output

Minimum box length 8

Formula: straight-pull box length = 8 × largest conduit

Step-by-Step Breakdown

1. Values used:

2. Largest conduit size = 1

4. Minimum box length = 8

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The math behind it

minimum box length = 8 × largest conduit size. Angle/U-pulls need different dimensions.

1 in conduit → 8 in box.

Angle pull?

Uses 6× the largest conduit plus the sum of others for each wall.