Figure 5-44. - Using the star for back-to-back bend.
Figure 5-45. - Box offset.
of stub you need, as described previously. To determine where to place the next stub, you first need an outside- to-outside measurement. This measurement is the distance from the back of the first bend to the point where you want the back of the second bend.
Two methods are used for making the second bend. The first is to subtract the take-up, use the arrow on the bender, and pull the bend in the same direction as you did the first bend. The second method, and probably the easiest, is to turn the bender around, line up the star on the bender with your outside-to-outside measurement, and pull the bend in the opposite direction, as shown in figure 5-44.
Table 5-3. - Offset Bending Formula
FORMULAAND CONSTANT MULTIPLIER FOR DETERMINING DISTANCE BETWEEN BENDS WHEN BENDING OFFSETS
|ANGLE OF BENDS||CONSTANT MULTIPLIER||SHRINKAGE|
|22 1/2°x 22 1/2°||2.6||3/16 PER INCH|
|30° x 30°||2.0||1/4 PER INCH|
|45° x 45°||1.5||3/8" PER INCH|
|60° x 60°||1.2||1/2 PER INCH|
OFFSET BENDS. - An offset bend is two equal bends in opposite directions. It is used to avoid contacting a part of the structure or to bring the conduit out from the structure to match a knockout in a box or panel. The angle of the bend in an offset depends on several things; how much offset is needed, how much room there is where the offset is going to be placed, and the type of obstacle you are avoiding. Figure 5-45 shows a box offset into a handy box. There is no way to mark the conduit for a box offset. The amount of bend and the distance between bends are estimated. The key to making good box offsets is practice.
Figure 5-46. - Bending an offset.Continue Reading