Some electrical wiring projects require the use of electrical metallic tubing (EMT), more commonly known as conduit. In particular, electrical codes require conduit in projects where the electrical cable has exposure to moisture or excessive humidity, and jobs where the wiring attaches to concrete walls. Many wiring projects require conduits to run around corners or other obstructions, so bending the straight conduit is necessary. Two of the most common bends are 90-degree corners and offsets.
Things You'll Need
- Tape measure
- Permanent marker
- Tube cutter or hacksaw
- Conduit bender
Measure the distance between each junction box and the corner. Make sure you account for the connectors that affix the conduit to the boxes. The run from the first box to the corner is the top of the bend, while the distance from the corner to the second box is the bottom of the bend. Mark the top bend distance on the conduit.
Measure the bend distance from the mark you made in Step 1 back toward the beginning of the top of the bend segment. Determine bend distance by the diameter of the conduit. For 1/2-inch conduit, the bend distance is 5 inches. For larger conduit (3/4-inch or 1-inch), the bend distance is 6 inches for the former and 8 inches for the latter. Mark the bend distance on the top of the bend segment. Using the proper bend distance prevents unusable crimped conduit.
Slip the conduit bender onto the top bend portion of the conduit. The fulcrum of the bender must align with the bend distance mark. With the conduit lying on the ground, face the top bend segment. Put one foot on the foot panel of the bender.
Bend the conduit. Pull the handle of the bender toward you, carefully and slowly with constant force. The top of the bend segment will rise up in the air. Pulling too quickly or forcefully will cause the conduit to crimp at the bend, rendering it useless (it is impossible to pull cable through a crimped conduit). The bender's protractor has angle markings to tell you when you have bent the conduit far enough.
Cut the bottom of the bend segment so it reaches the destination box.
Locate the painted end of the conduit to make offset bends easier to do. If there is no mark, measure in about 2 inches from the end of the conduit.
Make a 15-degree bend at the end of the conduit that will attach to the junction box. Offset bends are necessary because the junction box extends farther away from the wall than conduit mounted flush.
Roll the conduit over so the 15-degree bend faces down. Move the bender away from the end by about 2 inches. Pull the bender toward you until the end of the conduit beyond the first bend is parallel to the floor.
Tips & Warnings
- You can use offset connectors in place of the offset bend.
- Use the protractor to measure bends of angles less than 90 degrees. The bend distance does not change.
- Do not be discouraged if you do not get a good bend the first few times you try. Bending conduit requires practice.
- Most electrical codes prohibit the sum of angles in a run to exceed 360-degrees. A run begins where you can access the wiring to pull it through the conduit.
- "Wiring, 7th ed."; Creative Homeowner; 2010.
- Photo Credit electrician,electrical, image by Greg Pickens from Fotolia.com
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