45 degree conduit offset: multiplier and shrink
By Andrew ·
Quick answer
The multiplier for a 45 degree offset is 1.414, which the trade rounds to 1.4. Shrink is 0.414" per inch of height, but the usual rule of thumb is 3/8", which is short. A 10" offset at 45° has the bends 14 1/8" apart and shrinks 4 1/8"; the rule says 3 3/4".
45° offset marks
| Offset height | Distance between bends | Shrink |
|---|---|---|
| 1" | 1 7/16" | 7/16" |
| 2" | 2 13/16" | 13/16" |
| 3" | 4 1/4" | 1 1/4" |
| 4" | 5 11/16" | 1 11/16" |
| 5" | 7 1/16" | 2 1/16" |
| 6" | 8 1/2" | 2 1/2" |
| 7" | 9 7/8" | 2 7/8" |
| 8" | 11 5/16" | 3 5/16" |
| 9" | 12 3/4" | 3 3/4" |
| 10" | 14 1/8" | 4 1/8" |
| 12" | 17" | 5" |
| 15" | 21 3/16" | 6 3/16" |
| 18" | 25 7/16" | 7 7/16" |
| 24" | 33 15/16" | 9 15/16" |
What a 45 degree offset is for
Forty-five degrees is the angle you bend when the offset is tall and the room is short. The multiplier is only 1.414, so a 10" offset fits between bends 14 1/8" apart where 30° would need 20". It is the usual choice for stepping around a beam, a duct or a pipe that crosses your path, and for offsets around a box.
- Tall offsets in a short space. Six inches or more, where there is no room for 30° bends.
- Clearing something close by. The conduit leaves and returns to its line quickly.
- Saddle and box offsets. A 45° center notch is on nearly every hand bender, so the 45° mark is the one you can trust.
The price: shrink and wire pulling
A steep bend takes more conduit with it. At 45° the exact shrink is 0.414" per inch, so a 10" offset eats 4 1/8". The common rule of 3/8" per inch gives 3 3/4" and leaves the conduit short by the difference. If your run is measured from the end, use the exact figure.
| Offset height | Between bends | Shrink | Shrink (rule) |
|---|---|---|---|
| 4" | 5 11/16" | 1 5/8" | 1 1/2" |
| 6" | 8 1/2" | 2 1/2" | 2 1/4" |
| 8" | 11 5/16" | 3 5/16" | 3" |
| 10" | 14 1/8" | 4 1/8" | 3 3/4" |
| 12" | 17" | 4 15/16" | 4 1/2" |
Steeper bends also drag harder on wire. The NEC limits a run to the equivalent of four quarter bends, 360° in total between pull points, and an offset counts both of its bends, so one 45° offset uses 90° of that allowance. Plan for it when a run has several offsets.
Worked example: a 10 inch offset at 45 degrees
- Offset height
- 10"
- Angle
- 45°
- Between bends
- 14 1/8"
- Shrink
- 4 1/8"
- Between bends by the rule
- 14"
- Shrink by the rule
- 3 3/4"
Bending 45 degrees on a hand bender
The 45° mark is the one most hand benders are built around. The head usually carries a notch or line cut for the center of a 45° bend, with the degree scale on either side of it, so you can bend to the mark and check it against a level.
- Mark the first bend, then the second 14 1/8" further along for a 10" offset.
- Bend the first mark to 45° with the hook toward the end, and check the angle against the degree scale or a level.
- Roll the conduit half a turn, slide to the second mark and bend a second 45°.
- Lay the finished offset on a flat surface. Both legs should sit flat with no rocking.
Short offsets are the exception. Two 45° bends need enough straight conduit between them for the shoe to grip, so if the offset is small and the bends would run into each other, drop to 30° or less.
Get the marks for your bender
BendMate works this out from your bender’s radius and deduct, flags a bend that won’t work, and shows you every mark.
Common questions
What is the multiplier for a 45 degree offset?
1.414, rounded to 1.4 by most crews. A 6" offset needs 8 1/2" between bends.
What is the shrink for a 45 degree offset?
0.414" per inch of offset height. Charts that say 3/8" per inch have rounded down, which for a 10" offset leaves the conduit 3/8" short.
When do I use 45 degrees instead of 30?
When the offset is tall or the room between the bend and the obstruction is short. It trades extra shrink and a harder wire pull for a shorter run.