TradesHow this works
An offset jogs the conduit up and over an obstacle with two matching bends. Two numbers lay it out: the distance between the bends, which is the obstacle height times the multiplier for the angle, and the shrink, which is how much the conduit pulls back so you take it off your mark before bending.
The angle is the real decision. A shallow angle pulls easily and looks clean but spreads the offset out. A steep angle hugs the obstacle tight but is harder to pull and shrinks more. This gives the layout for every common angle and recommends one for an easy pull or a tight space, so you can mark and bend with confidence.
Common questions
How do you calculate a conduit offset?
For a two-bend offset, the distance between the bends is the height of the obstacle times a multiplier, and the multiplier is one over the sine of the bend angle. At 30 degrees the multiplier is 2, so a 6 inch offset puts the bends 12 inches apart. Then you subtract the shrink, which is the height times the tangent of half the angle, from your measured distance to the obstacle.
What is shrink in conduit bending?
When you bend an offset, the conduit pulls back a little because the diagonal path between the bends is shorter along the run than a straight piece would be. That pull-back is the shrink. If you do not account for it, the fitting on the end lands short. The shrink is the offset height times the tangent of half the bend angle, and you take it off your mark before the first bend.
What angle should I bend an offset?
Thirty degrees is the everyday default because the math is clean, the multiplier is exactly 2, and it pulls easily. Use a shallower angle like 22.5 degrees when you want the gentlest possible pull and have room for a long offset, and a steeper angle like 45 degrees when you need to hug the offset in tight to the obstacle, at the cost of a harder pull and more shrink.
Sources: Offset geometry (evergreen): distance = rise / sin(angle), shrink = rise x tan(angle/2) · Field multipliers and shrink constants: standard bending references. Engine version 1.0.0. Risk tier 1.