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Houses are wired in a few different ways. Inside of walls, ceilings, and floors, NM (Non-metallic) or Romex cable typically is used. Short runs of exposed wiring are usually protected by armored cable or BX. Outdoor wiring runs are often enclosed in metal conduit, called EMT, or electrical metallic conduit. EMT is fairly rigid, but it's also bendable, provided you have the right tool and technique. The right tool is a conduit bender, and the right technique mostly involves measuring properly... to account for the bend.Continue to 2 of 4 below.
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Things That You'll Need
Continue to 3 of 4 below.
- Tape measure
- Conduit bender (sized for conduit you’re bending)
- Framing square
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Measuring and Marking for a 90-Degree Bend
The first step in making a 90-degree bend is to determine how long the bend needs to be. Let’s say that you’re running a piece of ¾" conduit straight down a wall, and you need to turn it at 90 degrees and run it horizontally into a box that is 12" from the wall.
Look at the head of the conduit bender. You should find a notation about the take-up dimension. It might say something like, "Stubs 5" to arrow." This means that a 90-degree bend adds 5" to your horizontal... measurement. A "stub" is what electricians call a 90-degree bend. The arrow is near the front end of the head and indicates the beginning of the bend.
Your conduit needs to extend 12" from the wall, so the total horizontal dimension must be 12". If the take-up dimension of your conduit bender is 5", subtract 5" from 12", giving you 7". In other words, if you start the bend at 7" from the end of the conduit and the bend adds 5", you'll get a total of 12".
Measure from the end of the conduit and make a mark at 7" to indicate the start of the bend. Slip the end of the conduit into the bender so the 7" mark is aligned with the arrow.Continue to 4 of 4 below.
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Making the Bend
Pull the handle of the bender back towards you while applying heavy foot pressure to the bender heel at the back side of the head. Continue with a steady motion until the length of conduit on the floor reaches the 90-degree mark indicated on the side of the head.
Tip: Keep firm foot pressure on the bender head while pulling back on the handle. If you don’t, the bender can slide on the conduit and the measurement will come out all wrong.
Remove the conduit from the bender and check your work with... a framing square, which forms a 90-degree angle. The two sides of the bend should align with the two legs of the square. Next, check the length of the bend: position the conduit so the short end points straight up from the floor. Measure straight up from the floor to the end of the conduit; it should be 12". If so, you’ve done it! You're bending conduit like a pro!
If the bend is less than 90 degrees, put it back in the bender and bend it a little more. If you somehow end up with more than 12" on the horizontal, you can trim off the short end with a hacksaw or a tubing cutter. On the other hand, if you came up short, you'll have to start over with a new piece of conduit. Unfortunately, there's no way to stretch it!