Pulling more wire in existing conduit

[Marty Tippin]

I've got an existing 3/4" EMT conduit with 3 #10 stranded conductors in it, the run is about 50 ft with a couple of 90-degree turns. I need to pull 3 #8 stranded conductors for a new circuit - my calculation says I'll be at about 32% fill so I think I'm good code-wise.

When I pulled the first set of conductors, I neglected to drag a string along with the bunch. But I do have a 50 ft wire fish tape that I might be able to use.

Suggestions on the best way to proceed? Fish tape or no? Just pull out the existing #10s and re-pull all 6 wires?

[Frank Pratt]

Safest way is to tie a line onto the existing #10 wires & pull them out. Then pull in the new wires with the old #10s. Pulling new wires in with existing runs a risk of rubbing through the insulation on the old wires.

[Julie Moriarty]

It depends on what kind of fish tape you have and how difficult it was to pull the existing wire in. Some conduits have a "less friendly" inner surface that makes wire pulling harder. If you have the slinky-type fish tape, I'd take a shot at pushing it in and see how it goes. The first 900 will tell you how much resistance you'll have to deal with. Sometimes you can spin the fish tape to help it through. I've even used a variable speed drill to spin the tape but you have to be careful not to ruin the slinky.

If you have a steel fish tape with a proper head on it, you can try that but you should tape the end and place a little lubricant on it. You have to make sure, if you can't get it through and have to pull it out, there's no way the head can snag on the wire.

If the fish tape method fails and you can easily pull the all wire out, take them all out and tie either your fish tape or rope strong enough to pull the wire back in.

If the fish tape gets through, use lubricant to pull the new wire in. Same thing if you re-pull the entire set and are pulling in a string for future use. And try to make sure the wires don't cross over one another when doing the pull. If they do, your pull sting could get woven in the mess making your future pull more difficult, if not impossible.

[Marty Tippin]

Thanks all, the original pull was surprisingly easy (probably because it was 3 #10's in a 3/4 EMT), so I'm inclined to just pull them back out and re-pull the whole bundle, hoping that it doesn't bind up too much.

My fish tape is the steel kind with a big head on the end; I can just see myself getting it stuck halfway and making a mess of things.

[Robert Engel]

Just pull out the existing #10s and re-pull all 6 wires?
YES.

Even if you had a string, you couldn't pull them with wires in the conduit.

Side note: Seems to me that's a lot of wire for a 3/4 conduit.
I have pulled 6 #12's and that's about all I can do.

[paul cottingham]

That seems like a lot of conductors for a 3/4" conduit.

[John Lanciani]

That seems like a lot of conductors for a 3/4" conduit.


Code says up to 6x #8 is fine so 3x #8 & 3x #10 is no problem.

[Mike Heidrick]

Let us know how well it works.

[Greg R Bradley]

Let us know how well it works.


This sounds like where a bit of experience is worth a large amount of spec sheets, books, and theory