Pull Strings installed in 400' Conduit runs WITH cable

[SDavisky]

Have a project where the engineer is requiring pull strings be installed in new 400' runs with cable. We pulled the string in with the cable and naturally it would not move being engaed with the cable. Now he wants us to back up a mile and attempt to blow another string in. My position is that if you need to install more cable you simply use the old to pull in the new. It is silly to attempt to put a pull string in long dedicated conduits. I am looking for a code violation here with the string.....

 

[Hv&Lv]

Have a project where the engineer is requiring pull strings be installed in new 400' runs with cable. We pulled the string in with the cable and naturally it would not move being engaed with the cable. Now he wants us to back up a mile and attempt to blow another string in. My position is that if you need to install more cable you simply use the old to pull in the new. It is silly to attempt to put a pull string in long dedicated conduits. I am looking for a code violation here with the string.....

It would be easier to pull in two runs of new string with the old string you already have in there.
but, like you say.. Why???
we pull in a run of string with cables, but if we need to add a cable we simply put a string with the new cable as we are pulling it in.

 

[tom baker]

No code reference for pulls strings.If you try and blow in another string it may get hung up.
What are you using for a pull string?
Strongly recommend Mule Tape, its a braided fabric, easy to pull, does not burn thru 90s, we used the 2,000 rated version, and it has footage markers

 

[Hv&Lv]

Strongly recommend Mule Tape, its a braided fabric, easy to pull, does not burn thru 90s, we used the 2,000 rated version, and it has footage markers

totally agree here. The nice thing is for the most part the mule tape is free.
get up with a boring contractor.. they throw miles of the stuff in the dumpster.

 

[SDavisky]

No code reference for pulls strings.If you try and blow in another string it may get hung up.
What are you using for a pull string?
Strongly recommend Mule Tape, its a braided fabric, easy to pull, does not burn thru 90s, we used the 2,000 rated version, and it has footage markers

Using 200lb jet string. The existing wire is THWN and have a pscho inspector who declares any deviation in the nylon jacket damaged cable, honestly as easily as the nylon is ruffled or bunched I hesitate to attempt to install anything with the wire already in there. which is why I am looking for a code out against pull strings. Thought I found one the no other system in 300.8

I have never been a fan of pulling strings to leave in conduit with existing wire. Tangles or saws the existing wire too easily. These runs are 400' long

 

[cabledawg]

If you can, remove the other 2 cables and string and run all with a "swivel" so you avoid "twisting" the cable and string. Personally, used Mule tape! 400' is easy to figure 8. Once cables are out, You can attach your new cable to it and run it right back in. Hope it helps! P.S.

 

[LarryFine]

totally agree here. The nice thing is for the most part the mule tape is free.
get up with a boring contractor.. they throw miles of the stuff in the dumpster.

Don't fun and exciting contractors use it, too?

 

[Coppersmith]

I just searched my electronic NEC and was surprised to find several references to "string" but none were related to pull strings.

Festoon Lighting. A string of outdoor lights that is suspended
between two points.

(e.g., PV modules, ac output of utility-interactive
inverters), and also connected to sources having significantly
higher current availability (e.g., parallel strings of
modules, utility power), shall be protected at the source
from overcurrent.

(E) Disconnection of Series Battery Circuits. Battery circuits
subject to field servicing, where more than twenty four
2-volt cells are connected in series (48 volts, nominal),
shall have provisions to disconnect the series-connected
strings into segments of 24 cells or less for maintenance by
qualified persons. Non–load-break bolted or plug-in disconnects
shall be permitted.

 

[Coppersmith]

totally agree here. The nice thing is for the most part the mule tape is free.
get up with a boring contractor.. they throw miles of the stuff in the dumpster.

I was doing a job and really wanted some mule tape for a long heavy pull. I discovered it very pricey and ended up going another way. Makes me sad I threw away all that mule tape I used when working for the man.

 

[roger]

The existing wire is THWN and have a pscho inspector who declares any deviation in the nylon jacket damaged cable

I have never been a fan of pulling strings to leave in conduit with existing wire. Tangles or saws the existing wire too easily. These runs are 400' long

the Inspector is uneducated as far as the nylon jacket is concerned and needs to research UL info on THHN/THWN. The nylon jacket ads nothing to the insulation value and is actually removed for listing tests. It is basically for pulling reasons and from one manufacturers own words "it makes it sexy" or something to that effect.

Roger

 

[jusme123]

400’ run, good luck, that string will ‘corkscrew’ around that wire the entire length. IMO, pull a spare wire if its not too expensive

 

[kwired]

the Inspector is uneducated as far as the nylon jacket is concerned and needs to research UL info on THHN/THWN. The nylon jacket ads nothing to the insulation value and is actually removed for listing tests. It is basically for pulling reasons and from one manufacturers own words "it makes it sexy" or something to that effect.

Roger

Nylon jacket supposedly gives the insulation gasoline and oil resistance rating. Been a while but inspectors here used to be fine with nicked nylon jacket as long as not needing gasoline or oil resistance where it is being used.

 

[SDavisky]

the Inspector is uneducated as far as the nylon jacket is concerned and needs to research UL info on THHN/THWN. The nylon jacket ads nothing to the insulation value and is actually removed for listing tests. It is basically for pulling reasons and from one manufacturers own words "it makes it sexy" or something to that effect.

Roger

It would be easier to pull in two runs of new string with the old string you already have in there.
but, like you say.. Why???
we pull in a run of string with cables, but if we need to add a cable we simply put a string with the new cable as we are pulling it in.

Yes, that is what we did but the string won't pull and I won't let him tug it hard

 

[SDavisky]

Nylon jacket supposedly gives the insulation gasoline and oil resistance rating. Been a while but inspectors here used to be fine with nicked nylon jacket as long as not needing gasoline or oil resistance where it is being used.

If you can, remove the other 2 cables and string and run all with a "swivel" so you avoid "twisting" the cable and string. Personally, used Mule tape! 400' is easy to figure 8. Once cables are out, You can attach your new cable to it and run it right back in. Hope it helps! P.S.

I have used mule tape and it does save the pvc 90's for sure but I can't see being able to blow it 400's in existing cable.

 

[SDavisky]

Yes, that is what we did but the string won't pull and I won't let him tug it hard

I have used mule tape and it does save the pvc 90's for sure but I can't see being able to blow it 400's in existing cable.

It is underground at an airport so given the oil gas info, which I am sure they don't have, they would insist due to jet fuel from aircraft spills/crashes

 

[SDavisky]

Yes, that is what we did but the string won't pull and I won't let him tug it hard

the Inspector is uneducated as far as the nylon jacket is concerned and needs to research UL info on THHN/THWN. The nylon jacket ads nothing to the insulation value and is actually removed for listing tests. It is basically for pulling reasons and from one manufacturers own words "it makes it sexy" or something to that effect.

Roger

Do you have a source on the removed for testing?

 

[SDavisky]

400’ run, good luck, that string will ‘corkscrew’ around that wire the entire length. IMO, pull a spare wire if its not too expensive

the Inspector is uneducated as far as the nylon jacket is concerned and needs to research UL info on THHN/THWN. The nylon jacket ads nothing to the insulation value and is actually removed for listing tests. It is basically for pulling reasons and from one manufacturers own words "it makes it sexy" or something to that effect.

Roger

Totally with you on the uneducated....

 

[roger]

Do you have a source on the removed for testing?

Here is one article, I'll try to find the information on the listing test.

https://forums.mikeholt.com/attachments/1c6659pdp_152172-1-pdf.2380435/

Roger

 

[rambojoe]

Mule tape will most certainly burn through pvc 90°s...with a load on it- and a long run...

 

[texie]

Pull string, rope, mule tape, etc. is worthless and likely to cause damage if used in anything but an empty conduit. I ought to be banned from installing with conductors.