wire jacket incompatibility with pulling lubricant

[JimS]

Had reason to pull a cable out of a conduit due to damage from others work.  Cable is about 7 years old.  The cable is meant for direct burial and was in a buried PVC conduit.  The jacket is cracked in numerous places along the length.  Some of this may be from tension from breaking the conduit at one end with construction equipment but it appears the pull lube interacted with the cable sheath.  I am trying to get information on the sheath material.  Lube is Ideal 77.  I see that they say not for low density polyethylene so I am guessing that may be the material.  Their 77+ is a different formulation and "recommended for all cable types."  Now I am faced with what to do when replacing this.  The options seem to be:
 
- clean out the conduit (replacement is not practical).  This isn't going to be easy and likely not very effective but I could pull something through to get some of it and/or run soap and warm water through it.
 
- coat the cable with something to protect it - not sure what that would be...
 
- put tubing over the cable.  It's a bit less than 1/4" diameter so there is lots of room.  Run is about 60 feet.  Conduit is 3/4".
 
- just replace the cable (and attached sensor) and expect to replace again eventually.  It's low voltage so isn't a safety issue.  Based on the previous one it should last at least 10 years if undisturbed.
 
Any suggestions?

 

[pete_c]

In the early 1980's I had a home with a new detached garage built in the 1970's. 
 
The original home was built in the 1950's.
 
The electric was run in PVC using underground electric cable (from what I remember).  The original owners built a cement patio in front of the back end of the garage.
 
One day noticed by accident noticed that the electrical conduit in the garage was carrying AC voltage; which was not a good thing.  There was a sub fuse panel in the garage.
 
The garage was maybe 50-75 feet from the house.  I disconnected the electric at both ends and tried to pull it to replace it.  I couldn't from either end.  I did end up digging underneath the cement slab and found that a nearby tree / roots had pushed and stretched a section of PVC to the point of breaking/fusing the HV wires.
 
I cut out the section of PVC, ran new HV voltage wires (underground 1980's style) using the broken section to pull the wires to and from the garage to the home running the wires through a new section of PVC and just glued it there and all was well afterwards.
 
You mentioned cleaning out and replacing the line and that the run is 60 feet.  I would do this and if need be cut out a section in the middle, use the section to your advantage, pull the new cable and replace the PVC section with new.  (~ 30 feet PVC wouldn't be too difficult to work with).  Or replace run with new wire and or new PVC. 

 

[Del91574]

I would find out factually what the lube and installed cable are before assuming that one or the other interacted, as that's going to be the biggest item to consider. I doubt the cable is going to be polyethelene
 
Usually most lubes have a solvent that will clean them off, which would be what you'd need to consider. Barring that, you should be able to send a mouse or similar through the pipe to scour out what may be inside, but remnants would still remain.
 
Cracking sounds more like a freeze/thaw on a PVC jacket and/or aging more than anything else. Most likely, if the jacket is poly, it's going to be crosslinked if direct burial.