pulling wire through conduit

[4570Man]

Some time ago a licensed electrician told me just because wires will physically fit in a conduit doesn't mean you can, or should, do it. I believe there is also an amperage / heat rating limit as well. Probably not an issue with this job, but it's something I ran into with my construction a while ago.

Wires carry a lower amperage rating bundled vs loose. I’m not sure how many wires are bundled together factor into the rating.

 

[plowhog]

those are long bend corners

In my area I could not find long bend 90's in 1 inch. Not at HD/Lowes nor electrical supply. Had to make them myself. Maybe a regional thing?

 

[grsthegreat]

I generally pull another pull string through along with the wires as well on long runs. You never know if you're gonna have to pull another wire through in the future. There's a risk of burning the insulation on the existing wires if you pull more through in the future, but if you're careful when pulling the initial wires through, they generally don't twist around too much, and again, if you use plenty of pulling lube and pull slowly, it's not been a problem for me.

not going aroud 2 90 and a 45...oops, I read a bit farther and see those are long bend corners, They will still add some resistance though.

exactly. i could pull those wires thru 4 of these 90's//... been there done that. i actually pull lots of hot tubs with 4 #4 thhn runs thru at least 2 of the 90's and in 1" pvc conduit , and that is never an issue.

 

[grsthegreat]

In my area I could not find long bend 90's in 1 inch. Not at HD/Lowes nor electrical supply. Had to make them myself. Maybe a regional thing?

i actually prefer to make my own using a hot box. easier pull and can custom fit work better.

 

[MossRoad]

Another vote for @MossRoad's suggested method of connecting a rope or tape to the bundle. I don't trust the mesh for anything long or important, but I do use it.

I have used both fish tape and rope. Personally, I prefer rope, or pulling tape for longer runs.

From running fiber, I learned the trick of pulling an extra rope/tape when you do your main pull. It will save you grief later if you ever need it. The other trick I learned was to pull a line with a lube soaked raccoon tail or rag through the pull both ways before doing the real pull. It leaves extra lube on all the tight bits.

The first time that I saw the vacuum trick, I felt like I was watching magic. That thought was quickly followed by the thought of all the hours that I had wasted trying to fish something with fish tape. It works like a charm. Light rope and a plastic shopping bag and you are in clover.

All the best,

Peter

The first time I saw the vacuum trick was my first year at the newspaper. I was helping contractors install automatic paster units on the press that spin a new roll of paper up to speed, match it to the speed of the web on the expiring roll, then paste the new roll onto the expiring roll on the fly. Quite interesting. The contractors were looking for conduits that ran under and along the press under the concrete VS installing new conduit. They blew smoke from a little machine into an open conduit, then looked for it coming out. There were quite a few. When they'd find one they could use, they did the vacuum trick. Pretty ingenious.

 

[jigs_n_fixtures]

Wires are THHN, longest pull between pull points is 70' +/-, ells are long radius, new pvc conduit buried and above ground. One end of the long pull is in a 10" at grade pull box with the 45 bend and the other is a condule, all other bends in the remaining 40 feet are through condulets. I tried one of those "Chinese" finger puller once, in the distant past, with bad results. I like Caver's idea. I actually increased the conduit size from code required 3/4' to the 1" as I knew it would be difficult. Arm chair eval now, I probably should have used 1 1/4".

Ron

I strip the wires, and put the largest one forward to the front of the finger puzzle, and bend it back into a hook. Then keep putting them in a little further back until you have all of the wires in the puzzle then tape the whole thing. I haven’t had one pull loose that way yet.

 

[ultrarunner]

The first time I saw the vacuum trick was my first year at the newspaper. I was helping contractors install automatic paster units on the press that spin a new roll of paper up to speed, match it to the speed of the web on the expiring roll, then paste the new roll onto the expiring roll on the fly. Quite interesting. The contractors were looking for conduits that ran under and along the press under the concrete VS installing new conduit. They blew smoke from a little machine into an open conduit, then looked for it coming out. There were quite a few. When they'd find one they could use, they did the vacuum trick. Pretty ingenious.

How did they have smoke as I have to trace some underground and no idea where it goes?

 

[MossRoad]

How did they have smoke as I have to trace some underground and no idea where it goes?

They had a little box that produced smoke, stuck the hose in the open conduit, and smoke would come out on the end, electrical boxes, etc. Probably something like a fog machine. This was 1988. I don't know if they bought it or invented it or what. They were a company that specialized in installing retrofits of newspaper machinery. Rough bunch of guys, but very efficient. Wouldn't trust them anywhere near my family.

 

[MossRoad]

How did they have smoke as I have to trace some underground and no idea where it goes?

I wonder if you could inject sound into an open conduit and hear it as you walked around?

 

[MossRoad]

Or maybe compressed air?