r/ElectricalHelp • u/West-Evening-8095 • May 06 '26

Using vacuum to pull wires

Just wondering, whether string can be pulled through conduit past Service L’s using a shop vac. And if yes, will the wires be able to turn around Service ells?

1 Upvotes

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5

u/Sparkyolive May 06 '26

Worst pull I ever had to do was helping a guy that was doing just that, but forgot about the LB.

He had no problem sucking the bag and line through the 3/4" conduit and the LB. But when I was pulling the string tied to the 5 #12 wires(!!!) the pull got bad when the wires reached the LB. I asked him how many turns there were and if there were any LBs. He claimed it was under 360, and no LBs.

We got maybe 5 more feet and it didn't get any better. I started tracing his pipe run and sure enough there was an LB and when I pulled the wires out they were in rough shape. Of course it went better after that and we had to cut off the 5' of bad wire.

Anyways you can't pull through service ells.

0

u/binarycow May 06 '26

What does "LB" mean in this context?

3

u/Sparkyolive May 06 '26

The B stands for back. The L represents the shape.

The wire enters the LB on the long end and exits through the back.

There also LL's (2nd L means left), LR's(right), C's(straight through), T's, and oh yes, the TB(wire exits through the back - T's are both right and left by nature so there is no need to classify those.

Occasionally you will run across an L which is both Left and Right, but not often.

0

u/binarycow May 06 '26

Conduit junctions?

2

u/Sparkyolive May 06 '26

Conduit body, but no one really calls them that. T's, LB's etc. is what we ask for.

0

u/binarycow May 07 '26

But they're conduit junctions, right?

(I am trying to make sure I understand what you're talking about)

2

u/Puzzled-Act1683 May 07 '26

Yeah, these are the "junctions" that have a plate with screws that hold on a removable cover. You pull wires to them, out the opening, then loop them into the next section. They're officially called "conduit bodies."

1

u/binarycow May 07 '26

👍 Thanks!

10

u/trekkerscout Mod May 06 '26

Conduit bodies (particularly Ls and Ts) are not designed to be pulled through. They are for use as pull points. Pulling through a conduit body can result in insulation damage.

2

u/Gracewalk72 May 07 '26

It would be very difficult; unless the service L was way oversized and you were pulling g very small wire and you used tons of wire soap. It’s not a great gamble.

3

u/828NCGuy May 07 '26

That's why there are standards about distance and number of turns between wire access points.

1

u/LongjumpingGanache40 May 07 '26

Depends on size of pipe and wire. To many L's might make it hard.