TVL

1. GOOD
MORNING

2. Radius of
Bends

13. Bending for a
Given Rise

14. To bend 3/4-inch conduit, you’ll need a
3/4-inch hand bender. A 3/4-inch EMT
bender will also fit on a 1/2-inch rigid
metal conduit or 1/2-inch IMC. The 1/2-
inch rigid metal conduit and 1/2-inch IMC
have about the same outside diameter as
the 3/4-inch thin wall.

15. A very common bend in
electrical installation is a 90
degree bend also known as a
stub up.

16. The height the stub reaches
above its starting point at
floor level is known as the
rise.

17. The rise is made up of two
components:
the height of the curved portion
known as the takeup
the straight portion above the bend
known as the stub.

21. A common two-bend configuration is the
back-to-back bend which is typically a
mirror image bend of the 90-degree bend.
This type of bend occurs when you’re
required to attach a piece of conduit
between two outlet boxes on facing walls.
In this case, the first bend, the bend on the
left-hand side, is easy to make since it’s
made on a piece of straight tubing. The first
bend’s starting position is measured from
the end of the tubing.

24. An offset is a bend that takes the tubing out
of line with the run and then returns it in a
direction parallel to the original run. Offsets
are used to account for a change in elevation.
In an offset, you’ll see actually two separate
bends. The first bend takes the tubing out of
line, and the second bend returns it to the
same direction, on a different line of run.

26. Since offsets require two bends, they’re a
bit more difficult to execute than one
regular bend of 90 degrees. Many offsets
are small bends to match up fractions of
an inch and must be made by eye. Practice
and experience are the only way to learn
to make them expertly.

27. The larger offsets can’t be made by
eye; they have to be calculated and
measured. That’s a bit more difficult
and definitely requires some
practice. The trick to making offsets
is measuring and marking the
conduit for the two bends.

32. A rise over or under the beam is
called a saddle.

37. Conduit Run
Requirement

38. The main concern after installing the conduit is
whether the conductors that are going to be run
through the conduit can be pulled into the
conduit and withdrawn easily. When conductors
are pulled through conduit, insulation is subject
to injury and small wires can get stretched and
broken. As more and more wire is pulled through
the conduit, more and more insulation surface
area makes contact and the friction between
wires increases.

39. The tension on the wire being pulled becomes
greater and greater as the friction increases. A
rule of thumb is that no more than 1,000 pounds
of pull should be exerted on a conductor being
pulled through a straight run of conduit. Even
though you might use some sort of pulling
lubricant for difficult pulls, the tension increases
directly with the length of the pull and the
number of bends in the run.

40. The PEC states that a run of conduit between
outlets, between a fitting and an outlet, or
between an outlet and a fitting shall contain
not more than the equivalent of four 90degree
bends, including the bends located
immediately at the outlet or fitting. Therefore,
the total allowed is 360 degrees.

41. The total can be made up of four 90degree
bends, two 90-degree bends and four 45-
degree bends, or any other combination. You
can see that it will be difficult to pull the
conductor through each bend, and the more
bends you have, the more difficult the
conductor-pulling will be.

44. ACTIVITY

45. EVALUATION

46. ASSIGNMENT