From measuring to marking to cutting, conduit bending is truly one of the fundamental tasks for an electrician.
In Part One, we looked at how to mark conduit for a right-angle bend. You can use the same techniques for end bends and offsets. As before, we'll assume you're using a hickey. As always, make sure you ream the conduit with the proper tool before starting.
Making an end bend. Sooner or later, you'll need to make a small radius bend at the end of a conduit run. If you're using RGS conduit, you'll have to thread the conduit very close to the bend. This can be frustrating, if you don't know the right way to do it. Let's look at how to make an end bend successfully the first time.
First, here's a simple trick to preventing thread damage during the bending process. Thread the conduit while it is still straight, but go only about 3/4 of an inch. These threads will allow you to use a die later. They are not the threads you will use to assemble the conduit, so don't go longer than 3/4 of an inch. Screw a coupling onto the threads to protect them.
Now make your bend the normal way. This leaves you with a piece of conduit that has threads and a bend, but the threads are too far from the bend. That's only because we haven't finished the process.
Remove the coupling. Now, run your threading die over the threads and cut new threads until you have threads close enough to the bend to meet your installation requirements. Leave the die at the elbow end of the threads. Cut the threaded part to the right length. As you unscrew your die, you will clean up the threads on the piece of conduit you intend to use. You now have a conduit with the correct bend and undamaged threads right where you need them.
Making an offset. If you don't have an offset bending machine, use this technique. Fig. 1 (original article) shows a properly made offset. Distance A is the distance from your box to where you need the first bend to begin. Distance B is the distance within which the bends fall. Distance C is the amount of offset the bend will give you. You should make distance B as short as possible, especially if this is an exposed conduit. Keep all bends within the limits of the Code (Art. 346-349).
First, measure for distances A, B, and C. Then mark these measurements on the floor, in a way similar to that done in Part One. You'll need to draw the additional lines shown in Fig. 2 (original article). The run must lead up to point 1, extend diagonally to point 2, and then extend parallel to the straight section that preceded point 1.
To make the first bend, mark off the distance A from one end of the conduit. Slip your hickey on so it lines up with this mark. Place it in the position shown in Fig. 3 (original article). Press down on the unmeasured end of the conduit until the bend passes through the center of the rectangle in Fig. 2 (original article). Then, slip the conduit to the point where the second bend begins. Turn the unmeasured end upward. Pull down on the upturned end until you complete your offset.