Conduit bending
Conduit bending math comes down to multipliers and shrink. For an offset, multiply the offset depth by the angle's multiplier (2 for 30°, 1.4 for 45°) to get the distance between bend marks, and add the shrink to your measurement so the offset lands where you want it. For a 90° stub, subtract the bender's take-up from the stub height. The NEC limits a raceway run to 360° of bends between pull points, for example 358.26 for EMT.
Why conduit bending is on the exam
Bending questions test whether you can lay out marks before you bend. Most are quick multiplications: distance between bends, total shrink, a stub mark, or the degrees of bend in a run. Next to the other exam calculations, these are some of the easiest points on the test.
The key NEC rules
The NEC does not tell you how to bend, but it does limit how much you bend and how well.
- 360° between pull points. For EMT, 358.26 limits the bends between pull points (boxes, conduit bodies and similar fittings) to the equivalent of four quarter bends, which is 360° total. The same limit appears in the matching ".26" section of the other raceway articles, such as 344.26 for rigid metal conduit and 352.26 for PVC.
- Bends must not damage the raceway. For EMT, 358.24 requires bends to be made so the conduit is not damaged and its internal diameter is not effectively reduced. Minimum bend radii for field bends are found in Chapter 9, Table 2.
- Count every bend. Offsets, saddles and kicks all count toward the 360°, not just the 90s.
The 360° rule exists because every bend adds pulling tension on the conductors. For more raceway rules, see wiring methods and conduit fill.
Offset multipliers and shrink
An offset is two equal bends in opposite directions that move the conduit over by a set depth, usually to clear an obstruction or enter a box. The multiplier is the cosecant of the bend angle. Shrink is how much the conduit run shortens because of the offset.
| Bend angle | Multiplier (exact cosecant) | Trade multiplier | Shrink per inch of depth |
|---|---|---|---|
| 10° | 5.76 | 6 | 1/16 in |
| 22-1/2° | 2.61 | 2.6 | 3/16 in |
| 30° | 2.00 | 2 | 1/4 in |
| 45° | 1.41 | 1.4 | 3/8 in |
| 60° | 1.15 | 1.2 | 1/2 in |
Total shrink = offset depth × shrink per inch
Shallow angles need more room between bends but create less shrink and add fewer degrees toward the 360° limit. Steep angles fit tight spaces but pull harder. When you bend an offset toward an obstruction, add the shrink to the measured distance, or the offset ends up short.
Saddles
A saddle carries the conduit over an obstruction such as a pipe and back down to the original line.
Three-point saddle. One center bend and two outer bends in the opposite direction. The common layout is a 45° center bend with two 22-1/2° outer bends. The outer marks go 2-1/2 inches from the center mark for every inch of saddle depth, and the shrink is 3/16 inch per inch of depth. Move the center mark ahead by the shrink so the center of the saddle lands on the center of the obstruction.
Outer marks from center = saddle depth × 2.5Shrink = saddle depth × 3/16 in
Four-point saddle. Two offsets of equal depth, one going up and one coming back down, with the obstruction's width between them. Lay out the first offset, measure the obstruction's width from its second mark to find the third mark, then lay out the second offset. Total shrink is the shrink of both offsets added together.
Kicks and 90° stubs
A kick is a single bend of less than 90° that moves the conduit away from a surface, for example to line up with a knockout. Because it is one bend, it changes the conduit's direction instead of returning it to a parallel line. A kick combined with a 90° is called a kick 90. To move the end out a set distance, the angled length past the bend is roughly that distance times the angle's multiplier.
A 90° stub is laid out using the bender's take-up, the length the bend uses up. Subtract the take-up from the stub height to find the mark, then put the bender's arrow on the mark.
Mark from end = stub height − take-upCommon trade take-up values for EMT hand benders:
| EMT size | Typical take-up |
|---|---|
| 1/2 in | 5 in |
| 3/4 in | 6 in |
| 1 in | 8 in |
| 1-1/4 in | 11 in |
These vary by bender manufacturer and shoe, so always check the markings on the bender you are using. On the exam, use the take-up the question gives you.
For a back-to-back 90°, the second bend is measured from the back (outside) of the first 90°, and the bender's back-to-back mark is used to locate it.
Worked examples
Example 1: 30° offset. You need a 5-inch offset to clear an obstruction that starts 40 inches from the end of the conduit.
- Distance between bends: 5 × 2 = 10 in.
- Shrink: 5 × 1/4 = 1-1/4 in.
- First mark (nearest the obstruction): 40 + 1-1/4 = 41-1/4 in from the end.
- Second mark: 41-1/4 − 10 = 31-1/4 in from the end.
Example 2: three-point saddle. You need to cross a pipe that sits 2 inches off the surface, centered 30 inches from the end of the conduit.
- Shrink: 2 × 3/16 = 3/8 in.
- Center mark: 30 + 3/8 = 30-3/8 in from the end.
- Outer marks: 2 × 2.5 = 5 in on each side of the center mark.
Example 3: four-point saddle. An obstruction is 3 inches deep and 8 inches wide, starting 24 inches from the end. Using 30° bends, each offset needs 3 × 2 = 6 in between marks and has 3 × 1/4 = 3/4 in of shrink. Placing mark 2 at 24 + 3/4 = 24-3/4 in gives mark 1 at 18-3/4 in, mark 3 at 24-3/4 + 8 = 32-3/4 in, and mark 4 at 38-3/4 in. Total shrink for the saddle is 1-1/2 in.
Example 4: 90° stub. A 14-inch stub with 3/4-inch EMT and a 6-inch take-up: 14 − 6 = 8 in from the end.
Example 5: degree count. A run has two 90° bends, one 30° offset (60°) and a three-point saddle (45° + 22-1/2° + 22-1/2° = 90°). Total: 90 + 90 + 60 + 90 = 330°, which is within the 360° limit. Adding one more 45° offset (90°) brings it to 420°, so a pull point would be needed.
Common exam mistakes
- Using 1.4 for the 30° multiplier or 2 for 45°. Memorize the table.
- Forgetting that an offset counts as two bends. A 45° offset adds 90° to the run.
- Subtracting shrink when bending toward an obstruction. You add it.
- Adding take-up to the stub height instead of subtracting it.
- Counting a three-point saddle as 45°. It is 90° total.
Practice questions
Frequently asked questions
What is the multiplier for a 30 degree offset?
It is 2. Multiply the offset depth by 2 to get the distance between bend marks, so a 6-inch offset needs marks 12 inches apart.
How much shrink is there per inch on a 45 degree offset?
The trade value is 3/8 inch of shrink per inch of offset depth for 45° bends. An 8-inch offset at 45° shrinks the run by 3 inches.
How many degrees of bends are allowed in a conduit run?
No more than 360° total between pull points, which is the equivalent of four quarter bends. For EMT the rule is 358.26, and the other raceway articles have the same limit in their own ".26" sections.
What is the difference between a kick and an offset?
A kick is a single bend that changes the conduit's direction away from a surface. An offset is two equal bends that move the conduit over and return it to a parallel line. Try more problems on the practice test.