PVC electrical fittings for making corners

[Anthony Whitesell]

I am running some electric in some 3/4" PVC conduit. There are the LL/LR/LB fittings as well as a pull elbow for making corners. When would you opt to use the LL/LR/LB fittings versus using a pull elbow?

[Chris Padilla]

I use the LL/LR/LB when I need more room to make a turn (largish wires) or as a junction box to bring in another PVC conduit (instead of a metal or plastic box).

Sometimes the long narrow size fits better, too.

[Julie Moriarty]

We call the pull elbow you are referring to a "jake". Some municipalities in the Chicago area ban their use because of the sharp turn the wires have to make and the possibility the insulation can be damaged. I've used them when aesthetics come into play or when available space is tight. It's mostly a personal decision.

But you should limit wire fill. In a 1/2" pipe, you may want to limit the number of wires to something like (2-3) #12 or (3-4) #14. That angled cover can smash the wires if the fill is too great. You also must allow for access. The jake cannot be buried in a wall or ceiling. Same with unilets.

[Anthony Whitesell]

I'm working with 3/4" PVC.

What is a unilet?

[Julie Moriarty]

Maybe I misunderstood what you meant by a "pull elbow". What I was referring to when I said "jake" is something like this:

A unilet is an LB, LL, LR, T or C (straight through)

Jakes and LBs would most often be used around outside corners. LLs & LRs the same but they just locate the cover differently for access requirements.

If by "pull elbow" you meant this:

Then the uses for elbows and unilets are very different.

[Julie Moriarty]

I use the LL/LR/LB when I need more room to make a turn (largish wires) or as a junction box to bring in another PVC conduit (instead of a metal or plastic box).

Chris, you should never use a unilet as a junction box. They are designed for pull through use only.

[Chris Padilla]

I'm sure you are correct, Julie, but it worked out VERY WELL using one as a j-box...fit nicely between other conduits.

[David L Morse]

From the NEC:

314.16 Number of Conductors in Outlet, Device, and
Junction Boxes, and Conduit Bodies.
(C) Conduit Bodies.
(2) With Splices, Taps, or Devices. Only those conduit
bodies that are durably and legibly marked by the manufacturer
with their volume shall be permitted to contain
splices, taps, or devices. The maximum number of conductors
shall be calculated in accordance with 314.16(B). Conduit
bodies shall be supported in a rigid and secure manner.

Of course just because it's permitted by code doesn't necessarily make it good practice.

[Chris Padilla]

I wrote J-BOX in big black letters on it...that count?

Actually, it might well have the volume written on it but I'm not sure; I'll have to look.

Sometimes old breaker boxes are used to splice wires when an entire breaker box is being replaced with a new breaker box. Do those have volume numbers stamped on them? I'll have to look.

[David L Morse]

I think that the marking requirement applies to boxes less than 100cuin:

(2) Other Boxes. Boxes 1650 cm3 (100 in.3) or less, other
than those described in Table 314.16(A), and nonmetallic
boxes shall be durably and legibly marked by the manufacturer
with their volume. Boxes described in Table 314.16(A)
that have a volume larger than is designated in the table
shall be permitted

And that's my LAST NEC search for this thread!

[Anthony Whitesell]

Maybe I misunderstood what you meant by a "pull elbow". What I was referring to when I said "jake" is something like this:

The bag at Lowe's calls this a pull elbow.

[Anthony Whitesell]

The last time I checked on this, the 3/4" Lx could contain splices. The 1/2" Lx could not. No volume markings.

Interest note on the pull-elbows, Julie. I was looking at the pull elbow, and it is interesting to note that the perpendicular distance to the cover is less than the diameter of the conduit. Not cool. I wonder how that got approved.

I am going to have to dry "pull" the wires and see how they fit. I will be very bummed if they don't fit in the pull elbow but fit in the conduit.

[Chris Padilla]

swim-shed1.jpgswin-shed2.jpg

Here is one of these 'unilet' boxes used as a junction box. My wires to this sub-panel were just a bit too short so I used one of these (this is a 1" box) to extend the wire.

The sub-panel and this 'unilet' used to be on the side of my house and thus got painted but I moved them into this plastic shed (my swimming pool equipment shed).

So right or wrong, there it is...working just fine.

[Anthony Whitesell]

Does any one know

(a) what the allowed bend radius is for 3/4" conduit?

or

(b) what radius bend does the 3/4" tubing bender make?

[Julie Moriarty]

Does any one know

(a) what the allowed bend radius is for 3/4" conduit?

or

(b) what radius bend does the 3/4" tubing bender make?

(b) 6" for 3/4" EMT bender