4" saddle bend: 3-point and 4-point marks and shrink

3-point or 4-point over 4"

A 4" saddle takes the conduit over a larger pipe or a run of conduit on strut and brings it back to its original line. Which kind you bend depends on the top of the obstruction, not its height.

• 3-point saddle for something round or narrow, such as a pipe. The center bend sits over its middle and the peak touches only one point. Outer mark to outer mark is 20 7/8" with a 45° center and 16" with a 60° center.
• 4-point saddle for anything with a flat top: a box, a duct, a beam or a cable tray. It is two 4" offsets with a level run between them, and the box width only sets that run. The bends and the shrink stay the same however wide the box is.

If a 3-point saddle’s peak would have to sit across a flat top, it will not clear the edges. Switch to a 4-point saddle once the top is wider than a pipe.

45° or 60° center?

The 45° center is the usual choice. It is the gentler saddle, it uses only 90° of the 360° the NEC allows between pull points, and many hand benders have a notch cut for its center bend. The 60° center packs the saddle into 16" instead of 20 7/8", at the cost of 9/16" more shrink and a third more bend for the wire to pull through.

Pick 60° when the obstruction sits close to a box, a coupling or another bend and the longer saddle will not fit. Some heads, such as Klein’s and Milwaukee’s, mark a 60° center as well as 45°.

Worked example: a 4" saddle measured from the end

Say the middle of the obstruction is 36" from the end of the conduit. The first half of the saddle uses up conduit before it reaches the peak, so the center mark moves out by one side’s shrink, 13/16" for a 45° saddle. That is where the trade’s 3/16" per inch of height comes from.

1. Measure the height from the surface the conduit runs on to the top of the obstruction, plus anything on top of it you have to clear.
2. Mark the center at 36 13/16": the 36" to the middle plus the 13/16" of one side’s shrink.
3. Mark the outer bends 10 7/16" each side of it.
4. Bend the center to 45° on the center notch, then each outer mark to 22.5°, with the conduit rolled half a turn so all three bends lie in one plane.

A 4-point saddle over a 4" box

At 30°, each offset’s bends go 8" apart, twice the height. The level run between the second and third marks is the width of the box, and the saddle shrinks 2 1/8" whatever that width is. That is the same shrink as a 30° / 60° / 30° 3-point saddle of the same height, because both climb and come down at 30°. Each half is a 4" offset at 30°, which fits every shoe of a hand bender from 1/2" to 1-1/4" EMT.

Mark 2 is the 30" to the near edge plus the 1 1/16" the first offset shrinks. Mark 1 is 8" back from it, mark 3 is 12" past it, and mark 4 is another 8" on. A real bend is an arc, so the conduit finishes its climb a little past mark 2: leave some clearance at the edge of the box.

Mistakes, and what a real bender changes

• Using 2 1/2 × height. The rule gives 10", the exact figure is 10 7/16", so each outer mark lands 7/16" short.
• Not moving the center mark. Leave it on the middle of the obstruction and the peak lands 13/16" toward the end.
• Outer bends that do not match, which tips the far leg off the original line.
• Bending the outer marks the wrong way, so the conduit climbs again instead of coming back down. The hook faces the center bend.

A real center bend is an arc, so the top of the conduit sits a little below the sharp corner the chart assumes, and its arc is twice as long as an outer bend’s. On a low saddle and a big shoe the arcs can run together. BendMate works out the marks from your bender’s real centerline radius and deduct, raises the peak so the conduit still clears, and flags a saddle whose bends would collide. The free version covers offsets, 3- and 4-point saddles, 90s and kicks.