Conduit Offset Bend
Mark spacing, shrink, and multiplier for a two-bend conduit offset at a chosen angle.
Example
You enter
- Offset depth (in) 6
- Bend angle 30
You get
- Distance between marks 12 in
- Multiplier 2
- Total shrink 1.608 in
Details, formula, and sources
Distance between the two bend marks = offset / sin(angle) (the cosecant multiplier); total shrink = offset * tan(angle/2). The classic multipliers (30 deg = 2.0, 45 deg = 1.41, 22.5 deg = 2.61, 60 deg = 1.15) and shrink rules fall out of the trig exactly.
Standard conduit-bending trigonometry taught in the electrical apprenticeship and summarized in Ugly's Electrical References and the NECA bending guidance, by name. NEC Article 358 minimum radius and the 360-degree-per-run limit govern the install.
Free read-only access to the NEC at nfpa.org/freeaccess. The bending trigonometry is public first-principles math.
Estimate. AHJ and licensed electrician govern. Verify against the NEC edition adopted in your jurisdiction.
Field names used by the API: offset_in, angle_deg, mark_spacing_in, multiplier, shrink_in
- In-plane bends both bends in the same plane (a simple offset)method
- Minimum radius cross-check the conductor minimum bend radius with the cable-bend-radius tileNEC Article 358