15 degree conduit offset: multiplier and shrink

Where 15 degrees fits

Fifteen degrees is the middle ground between a long, lazy 10° offset and the 22.5° or 30° bends most people reach for. At 3.864 it needs about two-thirds of the room a 10° offset takes, yet the bends are still shallow enough that wire pulls through easily and the shrink stays small.

• Medium offsets of 2" to 4" along a wall or ceiling, where there is room for a few feet of travel.
• Clearing a trim ring, a locknut or the edge of a box on the way in, without a visible dogleg.
• Runs with a lot of bends before the next pull point. Two 15° bends count for 30° against the NEC limit of 360° between pull points, a third of what an offset of two 45° bends would use up.

Making a 15 degree bend

Many hand benders have no dedicated 15° mark, so the angle is usually set rather than read off the head. A few degree scales include a 15° line; look at yours before you reach for a level.

1. Find the 15° line on the head’s degree scale if there is one. If not, hold a level or a digital angle finder on the conduit.
2. Bend the first mark until the leg reads 15° off the original line, allowing a degree or so for springback.
3. Save a short scrap bent to 15° as a gauge. Laying it against the second bend is quicker than measuring each time, and it makes the two bends match.
4. Roll the conduit half a turn for the second bend, and check the two legs are parallel by sighting along them.

Choosing between 10, 15 and 22.5 degrees

The trade-off is room against shrink. Shrink per inch climbs from 0.087" at 10° to 0.132" at 15° and 0.199" at 22.5°, so the steeper angle also asks for more extra conduit. If you have the length, 15° gives you the smaller number; if you do not, move to 22.5°.