atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Cabling Telephones Systems Wiring Fish Tape for long flex

I read past posts, but couldn't find this specific info. I have a nightmare cable run to install through about 150 ft of flex conduit. The 1/8 in steel will not go through from either end.I found a break in the flex about 30 ft from one end where a previous installer broke the flex to negotiate two 90's-hopefully there are no more breaks cause we can't find any. Out here in the San Francisco area, almost noone uses conduit anymore, preferring Plenum cabling. Back in the good ole days in the phone company we used to carry a "big steel" for runs like these and very long runs. I can't remember if it was 1/4 in steel or 1/2 inch. Also, I've never used fiberglass fish tape. Would fiber be better for this run? I would assume it would be good for short distances but hard to force past 100 ft.

Providing no more breaks a vacuum might be the easiest method.

Unfortunately there are 2 cables in the conduit which would interfere w a seal. The tech onsite said these cables wouldn't budge to use a a pull wire and then pull them back in.

The most important part of the information you left out- what size is the conduit and what is it? Greenfield (FMC), Sealtite (LMC), plastic?

None of those are suitable for 150' runs so basically you are screwed even with nothing in it. Depending on the size, if it were me I would try a 1/8" tape with a spring leader but I wouldn't get my hopes up. There has to be some reason the existing runs can't be pulled out and that right there isn't good news.

-Hal

150' is too long a run to be installed with flex. Perhaps there's a pull box in the middle of the run (at the 100' mark) and that's why you can't pull the old cables out?

It's also possible that the old cables were installed with a crappy lubricant which has dried and hardened.

The fish snake you're remembering was probably a 1/4" one.

You might get better results with a rodder, but - as Hal said - How big is this conduit? What size are the cables already in it?

Why don't you just pull the new run in plenum and bypass the conduit?

Bill, I've never had any luck with a vacuum on flexible conduit (Greenfield) - too much air loss.

Sam

I've seen a number of Greenfield runs where the sparkies convoluted the flex so much you couldn't get anything through it. We've done some installations where we actually pull our cables through before the electricians finalize the placement. Here's one example of why we always pull a follow-line in with our cables for (possible) future use.

Also, I second Sam's analysis of air loss for a vacuum install.

Bill

I think Sam pretty well called it although I wouldn't count out the vacuum trick...or blowing. Yep, probably a box somewhere. Blow and listen for the whistle.

I have a 1/8th inch fiberglass tape (125') that is like pushing a wet noodle but it will go places no other tape will go....it works well with flex.

Good Luck.

ken may be onto something....maybe a softsnake

I have had good luck with a rigid fiberglass snake, it wasn't cheap, I think it was $150 for 100'

Not that I see this will help any but this is what I use in flex that I have to fish, it seems a little better than fiberglass to me.

https://cableorganizer.com/ideal-industries/31-090-zoom-fish-tape.html#image