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Electrical Raceway Layout

Conduit Bending Chart

Calculate conduit offset spacing, shrink, 90° stub marks, back-to-back references, and 3-bend saddle marks from source-checked field methods.

Interactive Layout

Calculate Conduit Bend Marks

Choose the bend, enter field dimensions, and transfer the calculated marks to the conduit.

Live Bend Layout

30-degree conduit offset bend layout An equal-bend offset with a 4-inch rise, 8-inch bend spacing, Mark A at 25 inches and Mark B at 17 inches from the conduit reference end. 8 in spacing 4 in rise Mark B · 17 in Mark A · 25 in
Measure every displayed mark from the same conduit reference end. The drawing explains the layout; it is not a scaled bend-radius template.
Primary mark
25 in
Second mark
17 in
Bend spacing
8 in
Offset / obstacle height
4 in

Stub deduct/take-up is bender-specific. Use the deduct stamped on your actual bender or a verified manufacturer value for that exact shoe. The offset multiplier table does not determine stub deduct.

Field Reference

Conduit Bending Multiplier and Shrink Chart

Equal opposing offset constants from Greenlee Site-Rite hand-bender guidance.

Use the multiplier for center-to-center bend spacing and the shrink value for total longitudinal shrink. Stub deduct is a separate bender-specific value.

Scroll horizontally to view additional columns. Column headers remain visible while scrolling.

Greenlee Site-Rite REV 02 Table 1 offset constants. Center-to-center spacing = offset height × multiplier; total shrink = offset height × shrink per inch of offset.
Bend pair Spacing formula Typical alignment Copy
10° 10° × 10° 6.0 1/16 in/in H × 6.0 Arrow
15° 15° × 15° 3.86 1/8 in/in H × 3.86 Arrow
22.5° 22.5° × 22.5° 2.6 3/16 in/in H × 2.6 Arrow
30° 30° × 30° 2.0 1/4 in/in H × 2.0 Arrow
45° 45° × 45° 1.4 3/8 in/in H × 1.4 Arrow
60° 60° × 60° 1.2 1/2 in/in H × 1.2 Arrow

These constants apply to equal opposing offsets using the Greenlee Site-Rite field method. They do not establish a universal 90° stub deduct, minimum code bend radius, or project approval.

How to Use the Bend Marks

Start from one clearly chosen conduit reference end and keep every dimension tied to that same end. For an equal-bend offset, the calculator gives the two arrow-alignment marks and the center-to-center spacing between them.

  1. Mark the calculated first bend location on the conduit.
  2. Measure the calculated center-to-center spacing to place the second mark.
  3. Align the first mark with the bender arrow and bend to the selected angle.
  4. Rotate the conduit 180° so both bends stay in the same plane, align the second mark with the arrow, and make the equal opposing bend.
  5. Inspect the completed offset before pulling conductors.

When working toward an obstruction, the Greenlee method adds total shrink to the measured obstruction distance before locating the obstruction-side mark. When working past an obstruction, the entered first-bend distance is the first mark and the second mark is one calculated spacing farther along the conduit.

90° Stub Deduct Is Bender-Specific

For a stub-up, deduct (often called take-up) is the distance subtracted from the desired finished stub height to locate the arrow mark. The correct deduct comes from the actual bender or its verified manufacturer instructions.

Stub mark Mark distance = desired stub height − bender deduct

Example: a 14 in desired stub with a verified 6 in deduct places the arrow mark 8 in from the conduit end.

Do not transfer deduct blindly between benders. Shoe geometry changes by conduit size and bender model.

Verified Greenlee Site-Rite examples

Limited model-specific examples from Greenlee 52034125 REV 02 specifications; verify the current manual and marking on the actual tool.
Greenlee model family Published deduct Typical listed EMT capacity
840A/AH, 840F/FH5 in1/2 in EMT
841A/AH, 841F/FH6 in3/4 in EMT
842A/AH, 842F/FH8 in1 in EMT
843A/AH, 843F/FH11 in1-1/4 in EMT

Offset Angle: Space vs Pulling Difficulty

Shallow offsets use more conduit length because the multiplier is larger. Steeper offsets shorten the run needed to gain the same height, but Greenlee cautions that steeper bends require more pulling force. Choose the angle that fits the available space while keeping the raceway practical to pull and inspect.

10° to 22.5°

Longer, gentler offsets. Useful when run length is available and a gradual direction change is desirable.

30°

Convenient field arithmetic because the multiplier is 2.0 and the source shrink constant is 1/4 in per inch of offset.

45° to 60°

Shorter offsets, but with greater change in direction. Evaluate pulling difficulty and project requirements before choosing a steep offset.

Worked Conduit Bending Examples

4 in, 30° offset toward an obstruction

Assumptions: equal opposing bends; obstruction is 24 in from the conduit reference end.

Spacing = 4 × 2.0 = 8 in. Shrink = 4 × 1/4 = 1 in.

Obstruction-side Mark A = 24 + 1 = 25 in. Mark B = 25 − 8 = 17 in.

Sanity check: both marks are positive and 8 in apart.

14 in stub with a verified 6 in deduct

Assumption: the actual bender is marked or documented for a 6 in deduct.

Arrow mark = 14 − 6 = 8 in from the conduit end.

Limitation: a different bender or shoe may use a different deduct.

4 in, 45° three-bend saddle

Assumption: Greenlee’s 22.5° outer / 45° center saddle method.

Center advancement = 4 × 3/16 = 3/4 in. Outer marks are 2.5 × 4 = 10 in on each side of the advanced center mark.

Sanity check: the outer bends are equal and the center bend is twice each outer angle.

Common Conduit Bending Mistakes

  • Using one deduct for every bender: verify the value stamped on the actual shoe or in its current manufacturer instructions.
  • Applying shrink in the wrong direction: use the selected layout method and keep the same conduit reference end.
  • Measuring to the wrong bender mark: offsets and stubs commonly use the arrow; back-to-back work uses the star/back-of-90 reference on supported benders.
  • Failing to rotate 180°: the second offset bend must stay in the same plane as the first.
  • Mixing inches and millimeters: switch units in the tool instead of manually mixing converted and unconverted dimensions.
  • Using the wrong shoe size: a mismatched bender can produce poor-quality bends and invalid field assumptions.

Bender Marks: Arrow, Star, Notch, and Angle Scale

Arrow
Common alignment reference for stub and offset bend marks in the Greenlee and IDEAL hand-bender procedures cited here.
Star
Back-of-90 reference used for back-to-back 90° bends on supported benders.
3-bend saddle notch
Center-bend reference used for the middle mark of the Greenlee three-bend saddle method.
Angle scale
Tool markings used to bend to the desired angle; the exact visual layout depends on the bender.
Generic conduit bender marking schematic A simplified original schematic showing the functional relationship of an arrow, star or back-of-90 reference, saddle notch, and angle scale. Exact positions vary by bender model. Arrow Star / back of 90 Saddle notch Angle scale follows the shoe arc
Functional schematic only—not a tracing of any manufacturer bender. Use the labels to identify the role of each reference, then verify its exact location on your tool.

These names describe the cited manufacturer methods, not a guarantee that every hand bender uses identical symbols. Match the procedure to the markings on the tool in hand.

Source, Scope, and Field Verification

Scope: common hand-bender layout methods for equal offsets, stub 90s, back-to-back 90s, and a standard 22.5°/45°/22.5° three-bend saddle.

Turn2Engineering uses Greenlee Site-Rite REV 02 as the controlling practical field reference for the offset constants and saddle method on this page. Manufacturer-specific deduct values are labeled as such and should be checked against the actual bender before use.

Dataset and Source-Check Details

Controlling field source
Greenlee 52034125 REV 02, 04/23
Offset data location
Table 1: Offsets, manual page 9
Saddle data location
3-Bend Saddle and Table 3, manual page 10
Stub method location
Marking Basics, manual page 8; deduct from the bender
Calculation basis
Spacing = H × multiplier; shrink = H × source shrink constant
Rights handling
Limited transformed reference only; no full manufacturer-table CSV
Publisher
Turn2Engineering
Maintenance class
Recheck when cited manufacturer manuals or supported models change

Conduit Bending Questions

The controlling Greenlee offset reference uses a 2.0 multiplier, so center-to-center bend spacing is twice the offset height.

Use the Chart for Constants, Then Verify the Bender

Use the interactive tool to turn common offset and saddle constants into actual conduit marks, then confirm shoe-specific values such as 90° deduct on the bender in hand. After the bend layout is established, continue with conductor fill and voltage-drop checks as required for the installation.

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