Preparing the Conduit for Bending
Measure the length of conduit you’ll need. Start from a corner or other orienting point, then measure from the corner to where the conduit will end (usually a converter box). Place a pencil mark on the conduit at the measurement where the corner should be. Make sure that you have some extra conduit on hand if you do not do it often. It’s easy to make a mistake regarding the take up of the bend, especially when performing more complex bends.
Calculate the amount of extra conduit you will need. When you bend conduit, you lose length as the conduit is bent in the direction of another plane. The amount of conduit you’ll need for the corner depends on the diameter of the conduit. A ½-inch (1.27 cm) pipe requires 5 inches (12.7 cm) of extra conduit, ¾-inch (1.905 cm) conduit takes 6 inches (15.24 cm) and a 1-inch (2.54 cm) conduit pipe requires 8 inches (20.32 cm).
Cut the conduit to the size you need, removing burrs from the end. Use a conduit reamer or knife to scrape the edges to get rid of any fragments, or burrs. Ensure that all burrs are removed before you install the conduit. Otherwise, this may cause a short or ground fault after the wire has been installed.
Making a Basic Bend
Work with a bender. A bender is an essential for any conduit bending project. The tool should fit the correct sized conduit tube that you need to use. Before you start the bending process, locate any instructions on the conduit bender that may describe how much conduit should remain past the bend to the end of the bending shoe. If there are no instructions on the bender, follow the standards (as listed above) for the size conduit you are using. As you'll see, the bender should have three or four distinctive features: The 90° mark. This is the point at which a bent conduit has reached a right angle. It is one of the most commonly used angle marks. Other angle marks. Common angle marks include the 10°, 22.5°, 30°, 45°, and 60°. Stub height mark. This mark will usually list a number (like 6 inches (15 cm)) to use for the bender take-up.
Slide the conduit into the bender. Be sure to leave the appropriate amount past the arrow on the bending shoe. Set the conduit on a level, firm ground and place your foot firmly on top of the foot of the bender. The top of the pipe should come through the bender, so your foot should be able to steady it as well.
Pull the bender handle toward you to create the bend. Use a firm and steady motion to avoid kinks or crimps in the conduit. Make sure your foot and hand remain securely on the bender; any small slip in the conduit can cause an off-centered bend, and you will need to start over with a new piece of conduit. Make sure that you apply firm pressure with your foot to avoid creating kinks in the bend. Be aware that when you bend, you may need to overbend slightly to compensate for any spring back in the conduit. Do this slowly and carefully.
Bend until your bender reaches the 90° mark or other desired corner angle. Most benders include marks for 15°, 30°, and 60° as well. Go slow and take your time.
Check to make sure your bend is the right angle. You can do this either holding it up to the wall or using a level held snugly against the front side of the pipe. You can also hold it to a surface you know is level to check it.
Mastering Bending Techniques
Learn how to air bend in a pinch. Most of the time, you'll use your bender and the floor to bend the conduit. But sometimes, especially if you're doing a more complicated bend, like a back to back bend or an offset bend, you won't be able to use the floor as a fulcrum. If you need to use an airbend to twist your conduit, here's how: Put the hilt of the bender on the ground. Secure it in place with both feet or another reliable anchor. Keep the bender straight and let your body apply the pressure to the conduit. Don't try to use the bender to airbend. Make sure the head of the bender stays rigid as the conduit bends into the cradle.
Use the correct-sized bender for the type of conduit you're using. While it's tempting to think that your bender is a one-size-fits all tool, it's not. Be prepared to use or buy a bender for each different type of conduit you need to bend. For example, ⁄2 inch (1.3 cm) conduit shouldn't be bent using a 1 inch (2.5 cm) bender.
Use a level and protractor to double-check the measurements. Don't be afraid to use a water level and protractor to measure your angles with certainty. Of course, sometimes getting the exact angle on a bend isn't important; but often, whole conduit systems will be thrown out of whack if just a single angle is off 5°.
Take your time to make sure the bends are aligned. This is particularly important on conduits with multiple bends. Be careful about creating a dog leg when you shape conduit. A dog leg is where multiple bends on a line don't line up in the same plane. Examine the alignment in all directions before bending off.
Experiment with different kinds of bends. A typical electrical job will require more than simply a 90° stub-up bend. In fact, there are dozens of different combinations of bends you can use. It's helpful to experiment with bending a couple of them. Remember that practice makes perfect! Back to back bends. Two 90° stub up bends on opposite sides of the conduit, with both stubs moving in the same direction. Offset bends. Almost a sidewinder pattern, this bend incorporates two 45° angles in order to shift the conduit beside an obstacle but still run in parallel with the old line. Three- and four-point saddle bends. A variant of the offset, where the 45° bend returns back 45° after clearing an obstacle. A four-point saddle offers more clearance than a three-point saddle.
Be patient and keep practicing. Bending conduit is an art and can take some time to do correctly. Don’t get frustrated if it doesn’t come out the way you want it to, just be patient and keep practicing. In time, your skills will improve.
Comments
0 comment