144 Section 3 Installation Copyright Goodheart-Willcox Co., Inc. PROCEDURE Stub Bend A stub bend is a 90° bend that usually brings a horizontal run of conduit up or down to an outlet box. Practicing this basic bend will help you become familiar with the conduit bender. See Figure 10-5. 1. Measure the height of the total bend. This is typically from the bottom of the horizontal conduit to the bottom of an electrical box (if the bend is pointing upward). Subtract the radius of the conduit bender from the total height. The radius should be noted on the head of the bender. The resulting num- ber is the distance to mark from the end of the conduit. For example, if the total height needed is 10″ and the bender’s radius is 5″, mark the conduit 5″ from the end. 2. Place the conduit in the bender with the mark aligned to the bender’s arrow. 3. Press down on the foot pedal of the bender (while guiding the handle to keep the bend perpendicular to the fl oor) until the stub is 90°. Apply pressure on the bender with your foot. Your hand should only guide the direction of the bend. 4. Use a torpedo level to confi rm that the stub is vertical. When the horizontal sec- tion of the conduit is level, the stub should be plumb (perfectly vertical). 10.1.3 Bending Metallic Conduit The purpose of bending conduit is to route it around corners and over obstructions. There are numerous specially manufactured fi ttings available that can be used to make turns in conduit, but bending is usually preferable to using fi ttings. A fi eld bend is a bend that is made on the construction site. This generally saves time and is far more economical than installing fi ttings. Most bends in EMT are made with a hand tool called a conduit bender. Always use the correct size of bender for the conduit you are bending. This tool is designed to create a bend with the proper bend radius. The NEC lists the minimum radius of conduit bends in Chapter 9, Table 2. Typical bends include stub (often called a stub-up), back-to-back, offset, and saddle. The following sections will help you make these fun- damental bends. Bending conduit is an impor- tant skill that you can master with practice. Offset Bend The offset bend is used when the conduit must go around an obstruction or when the plane of the conduit must change slightly. Generally, off- sets may be done at almost any angle, but shal- low bends (those at smaller angles) are easier to pull wires through than deeper bends. Deeper bends bring the offset closer to the obstruction but make it more diffi cult to pull the wires. Goodheart-Willcox Publisher Figure 10-4. The burr created by cutting EMT must be removed or it may damage the insulation when wires are pulled through the conduit. Removing Burrs from Metal Conduit Use a flat file on the outside Use a round file on the inside Deburring tool for outside and inside