Straight Pull vs Angle Pull vs U-Pull Explained

> **Quick Answer:** U-pulls typically require the largest box. For the same conduit size, a U-pull and angle pull both use the 6× formula plus additional conduits on the same wall, which usually produces a larger dimension than the 8× straight pull formula. When you have multiple large conduits on one wall making a U-turn, the required box depth can be significantly larger than the straight pull length.

The Three Pull Types — And Why They Matter

Before you can size a pull box under NEC 314.28, you need to identify what type of pull you're making. The NEC uses three distinct configurations, and each one gets a different formula. Get the pull type wrong and your box might be undersized — which means a failed inspection, a rework order, and a conversation with the foreman nobody wants to have.

The pull type isn't about preference. It's determined by how the conduits enter and exit the box. The conductors inside follow the conduit routing, and the box has to be large enough that those conductors can make the bend without violating their minimum bending radius.

Straight Pulls

A straight pull is exactly what it sounds like. Conduits enter one wall of the box and exit through the directly opposite wall. The conductors go in one side and come out the other without changing direction.

**Formula:** Box length (in the direction of the pull) = 8 × trade size of the largest conduit

**Real installation scenario:** You're running a feeder from a transformer room straight through a chase wall to a distribution panel on the other side. Two 2-inch conduits enter the left wall and exit the right wall, parallel to each other. That's a straight pull. Box length = 8 × 2 = 16 inches.

The straight pull formula gives you a relatively compact box compared to the other types. The 8× multiplier exists because conductors need room to flex during installation, not because they're bending — they're essentially going straight. The length accounts for the slack needed to pull conductors without kinking them at the conduit entrance.

Angle Pulls

An angle pull happens when the conductors enter through one wall and exit through an adjacent wall — a 90-degree change in direction. This is the most common scenario in real installations, because conduit runs regularly need to turn corners.

**Formula (applied to each wall with conduit entries):**

Distance from that wall to the opposite wall = (6 × largest conduit on that wall) + (sum of all other conduits on that same wall)

You apply this independently to every wall that has conduit entries, and the box dimensions must satisfy all resulting values simultaneously.

**Real installation scenario:** You're routing a 480V motor feeder through a mechanical room. The conduit enters through the bottom of the box (coming up from underground) and exits through the left wall (going horizontally to the motor control center). Bottom wall has one 3-inch conduit. Left wall has one 3-inch conduit.

- Distance from bottom wall to top wall: 6 × 3 = 18 inches

- Distance from left wall to right wall: 6 × 3 = 18 inches

You need an 18×18 box minimum. Now add a second 2-inch conduit entering that bottom wall for a branch circuit:

- Distance from bottom wall to top wall: (6 × 3) + 2 = 20 inches

The box grows to 20×18 just from adding one more conduit on the bottom wall. This additive behavior is why the formula matters and why you can't eyeball it.

Use the [pull box sizing calculator](/pull-box-sizing-calculator) to handle multiple conduits on multiple walls without arithmetic errors.

U-Pulls

A U-pull (also called a parallel pull) is when conductors enter and exit through the same wall. They come into the box through one conduit, make a U-turn, and leave through another conduit on the same wall.

**Formula:** Distance from the entry wall to the opposite wall = (6 × largest conduit on that wall) + (sum of all other conduits on that same wall)

The formula is identical to the angle pull formula because the physics is the same — the conductors are bending through the same arc. What's different is the geometry: instead of turning a corner, the box is providing a reversal chamber.

**Real installation scenario:** A switchboard installation where two 4-inch conduits come up through the floor slab and loop back down through the same slab, serving circuits on opposite ends of the room. Both conduits enter and exit through the bottom wall.

- Distance from bottom to top: (6 × 4) + 4 = 28 inches

That's a 28-inch depth box just to meet the NEC minimum. Add a third 2-inch conduit on the same wall: (6 × 4) + 4 + 2 = 30 inches. You're now looking at custom steel fabrication or a large listed enclosure, not a stock box from the supply house.

Side-by-Side Comparison: Same 3 Conduits, Three Pull Types

Let's take a real example and run it all three ways to show how dramatically the box size changes.

**Setup:** Three conduits — one 3-inch, one 2-inch, one 1.5-inch — all carrying conductors that need to be routed through a box.

**Scenario A — Straight Pull:**

All three conduits enter the left wall and exit the right wall.

- Box length = 8 × 3 = **24 inches**

- Width needs to accommodate conduit spacing, but the pull-direction dimension is just 24 inches.

**Scenario B — Angle Pull:**

All three conduits enter the bottom wall and exit the left wall.

- Bottom wall to top wall: (6 × 3) + 2 + 1.5 = 18 + 3.5 = **21.5 inches** → round up to 22 inches

- Left wall to right wall: (6 × 3) + 2 + 1.5 = **21.5 inches** → round up to 22 inches

- Minimum box: **22×22 inches**

**Scenario C — U-Pull:**

All three conduits enter and exit the left wall.

- Left wall to right wall: (6 × 3) + 2 + 1.5 = **21.5 inches**

- But you also need spacing between the conduits on the left wall: NEC 314.28(A)(2) requires the distance between conduit entries on the same wall to be at least 6× the largest conduit = 6 × 3 = 18 inches between the center of the 3-inch conduit and the nearest conduit on the same wall.

The U-pull box ends up needing significant width (left wall length) to space the conduits apart in addition to the depth requirement. A 22×36-inch box isn't unusual for this configuration.

Compare: the straight pull was 24 inches in one direction. The U-pull might require 22 inches deep and 36 inches wide. That's more than twice the material.

How to Identify Pull Type from Drawings

On conduit routing drawings and single-line diagrams, look at how the conduit home-runs are drawn relative to the pull box symbol.

- **Straight pull:** Conduit lines enter and exit on opposite sides of the box symbol, with arrows going in the same direction.

- **Angle pull:** Conduit lines enter one side and exit an adjacent (perpendicular) side. The routing makes a 90-degree bend at the box.

- **U-pull:** Conduit lines enter and exit through the same side. You'll often see two arrows pointing in opposite directions from the same wall of the box symbol.

In practice, it helps to sketch the box and draw the conduit entries on each wall before running the formula. Even a rough pencil sketch eliminates most confusion about which type you're dealing with.

The Common Confusion: When an "Angle Pull" Is Actually a Straight Pull

Here's something that trips up a lot of journeymen: a pull box sitting at an elbow in a conduit run isn't automatically an angle pull.

If the conduit enters the left wall and exits the bottom wall, yes — angle pull. But if the conduit enters the left wall, makes a 90-degree bend *outside* the box using an LB or conduit elbow, and then enters the right side of the box, the conductors inside the box are going straight through. That's a straight pull.

The formula applies to what the conductors are doing *inside* the box, not to the conduit routing outside. Pull type is determined by the entry and exit walls for each conductor run, not by the bends in the conduit system surrounding the box.

Conductor Bending Radius Inside Each Pull Type

NEC 300.34 sets minimum bending radii for conductors, and those radii are the physical reason the pull box formulas exist.

For a **straight pull**, conductors aren't bending inside the box — they're just being pulled through. The 8× formula accounts for the work length needed to manipulate the conductors.

For an **angle pull**, conductors are making a 90-degree bend. The 6× formula ensures the bend radius is large enough that the conductor insulation doesn't crack and the copper doesn't kink. A 3-inch conduit has a roughly 3.5-inch inside diameter, and the conductors filling it can be 500 kcmil or larger. Those conductors need 18 inches of room to make a bend without damage.

For a **U-pull**, conductors are making a 180-degree reversal. The bend radius is the same as an angle pull (same 6× formula), but the conductor has to complete a full U-turn, which is why the spacing between conduit entries on the same wall also matters.

Choosing the Pull Type When You Have a Choice

Sometimes the routing isn't fixed — you have flexibility in how you run the conduit, which means you can influence which pull type you end up with.

**When possible, prefer straight pulls.** The 8× formula generally produces a smaller box dimension than the 6× formula with additive conduits, especially when you have multiple large conduits. Running conduits through opposite walls rather than adjacent walls can reduce box size significantly.

**Avoid U-pulls for large conduit bundles.** The spacing requirements between conduit entries on the same wall can force very wide boxes. If the installation allows it, split U-pull conduits onto opposite walls (making them a straight pull) to cut your box width in half.

**Use angle pulls where space dictates a corner.** When the conduit routing has to turn a corner, the angle pull formula is unavoidable. Plan for it in the design phase rather than discovering the box doesn't fit after the frame is in.

For full formula calculations on any pull type, the [NEC 314.28 box sizing tool](/pull-box-sizing-calculator) handles all three configurations and shows you the controlling dimension for each wall. Check the [about page](/about) for details on the calculation methodology.

For a deeper look at the NEC rules behind these formulas, read [NEC 314.28 explained](/nec-314-28-explained), and see [when do you need a pull box](/when-do-you-need-a-pull-box) for guidance on where in a conduit system pull boxes are actually required.