How to Run Electrical Conduit
Planning, cutting, bending, and installing EMT and rigid conduit for electrical rough-in — including underground runs.
Step-by-Step
- 1
Plan the route
Plan conduit runs to minimize bends — each 90-degree bend adds friction equivalent to 10–15 feet of straight run. NEC limits runs between pull points to 360 degrees of total bends (four 90s). Map your route before cutting anything and identify all box and pull point locations.
- 2
Size the conduit
Conduit must not exceed 40% fill of its cross-sectional area per NEC. A 1/2-inch EMT holds up to 3 #12 THHN conductors. A 3/4-inch EMT holds up to 5 #12. Use a conduit fill calculator for mixed wire sizes. Always leave room for future wires — upsize when in doubt.
- 3
Cut conduit to length
Cut EMT with a hacksaw or EMT pipe cutter. Deburr every cut end — a sharp edge will cut through wire insulation. Measure from center of bend to end for accurate cuts after bending.
- 4
Bend the conduit
Use a hand bender or mechanical bender. Mark your bend location with a pencil, align with the arrow on the bender shoe, and make the bend. A 90-degree stub-up: mark your stub length minus 5 inches (the bender's gain), bend, and the stub comes out at your mark. Practice bends on scrap before bending your good conduit.
- 5
Install conduit hangers and straps
Support conduit within 3 feet of every box or coupling, and every 10 feet in between. In seismic zones, lateral bracing is also required. Keep runs parallel and plumb — sloppy conduit work is a code violation and looks unprofessional.
- 6
Install pull boxes at bend accumulations
Install pull boxes or conduit bodies wherever bends accumulate to more than 360 degrees, or where runs exceed 100 feet between pull points. Pull boxes must remain accessible — never bury them in a wall or ceiling.
- 7
Install a pull string in every conduit
Before closing any conduit run, install a pull string. Tape the string to the deburring end and fish it through. Tie the string to a nail inside the box — this allows future wire pulls without disassembly. Never leave empty conduit without a pull string.
- 8
Underground runs
Use rigid galvanized conduit or schedule 40/80 PVC underground. PVC requires larger radius elbows (LB bodies don't work underground). Minimum burial depth for PVC is 18 inches for residential branch circuits; 24 inches under driveways. Concrete-encased elbows reduce depth requirements.
Pro Tips
- → Use 'kick and saddle' bends to route conduit around obstacles — they look clean and are faster than cutting and installing conduit bodies.
- → Label both ends of every conduit with the circuit number before pulling wire — it saves hours at panel termination.
- → Pull string in every conduit, always, no exceptions. The next electrician (or you, 5 years later) will thank you.
Watch Out
- ! Never exceed 40% conduit fill — overloaded conduit overheats wiring and is a fire hazard.
- ! Call 811 before any underground conduit work. Even on your own property.