How to Bend PVC Conduit

Why PVC is different

Schedule 40 and Schedule 80 PVC conduit is rigid plastic. Instead of being pulled round a shoe, it is heated until it is soft, shaped, and held until it cools and keeps the shape. Schedule 80 has the thicker wall, so it takes longer to heat through.

Factory elbows come in standard angles and radii. Heat bending covers the offsets, saddles and odd angles you cannot buy, and lets you match a bend to the job.

What you need

• A heater made for bending PVC: a heater box, or a heat blanket that wraps round the conduit.
• Gloves, because the softened conduit is hot.
• A tape, a marker, and a level or angle finder.
• A wet rag or water to cool the bend.
• For larger sizes, a plug for each end, so the conduit keeps its round shape as it bends.
• A form, or a flat surface with the bend drawn on it, if you are bending several the same.

Heating and forming a bend

1. Mark the center of the bend, and the length you will heat on either side of it.
2. For larger sizes, plug both ends before heating.
3. Heat the marked length, turning the conduit as it heats so it warms evenly all the way round. Follow the heater’s instructions for time and temperature.
4. When the whole length is soft and flexible, take it out and form the bend: by hand, against a form, or over a line drawn on the floor. Keep the curve smooth and do not let it flatten.
5. Hold it in shape until it cools. A wet rag or water on the bend speeds this up and sets it.
6. Check the angle and the plane before the next bend, just as with steel.

Marking offsets on PVC

There is no shoe, so there is no deduct and no arrow: mark the center of each bend and heat around it. The offset triangle is the same as for steel, so the multipliers work exactly the same way.

A heat bend’s radius is whatever you form it to, so a real offset can differ a little from the multiplier’s sharp corners. Bend the first one, hold it against the job, and adjust before you do the rest. BendMate’s bender library covers EMT, rigid and IMC, but the multiplier method is in the free version and gives the bend-center marks for a PVC offset or saddle.

The code: radius and the 360° rule

NEC 352.24 holds a PVC field bend to the minimum radius in Chapter 9, Table 2, measured to the centerline. Heat bends are not made on a one-shot or full-shoe bender, so they use the table’s “other bends” column.

NEC 352.26 limits a PVC run to the equivalent of four quarter bends, 360° in total, between pull points, the same as metal conduit. Count both bends of every offset. Follow your local code and inspector where they differ.