Abandoned Underground Power Cable at Station

[pwrtran]

HI all,

Can someone share your practice of dealing with abandoned underground feeder cables from substation to raiser poles on street, which the cable cannot be pulled out due to the ruptured ducts.

Thanks

 

[rcw retired EE]

If junk price of copper in the cable is less than cost of excavating the cable, cut it off at each end and abandon in place.

 

[stevenal]

NESC: "Lines and equipment permanently abandoned shall be removed or maintained in a safe
condition."

So abandoned lines are not truly abandoned, they must still be maintained.

 

[pwrtran]

rcwilson, should or shouldn't be grounded at each end?
stevenal, the cable cannot be removed without big excavation work due to the rupture of the duct somewhere don't know.

 

[cranky108]

Adverise for free copper to anyone who can pull it out.

 

[rcw retired EE]

Steven brought up a good point. In our work we abandon direct-buried temporary construction power cables under the completed power plant. Removal would require a lot of excavation. Cables are cut off a few feet below the surface and the area backfilled so there are no accessible ends. The cable route is shown on the client's as-built drawings.

Coming out of a substation, there may be a concern about transfered GPR potentials during a ground fault if you ground the cable at either end.

 

[ScottyUK]

I would earth both ends if possible. That gives you some chance of being able to use an inductive coupler to trace the cable at some point in future.

 

[waross]

If the duct damage has also damaged the cable, or if you are able to intentionally pull the cable hard enough to damage it where the duct is damaged, it may be possible to locate the damage with a Time Domain Reflectometer.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[gattie]

If the cables are multicore & you can expose the ends of cores,
try pulling the cores out one at a time with a Tirfor Winch similar device.
It worked for a scrap copper thief that pulled the 120mmm2 copper cores out of a redundant underground swa cable.
Mind you, he had a steam locomotive at his disposal!

 

[pwrtran]

Hi gattie, that is interesting LoL !
Thanks

 

[BJC]

Try a D-9
"There are no jobs to big, just machines that are to small."

 

[PersonalProfile]

Not sure about your local requirements, though in AU, AS3000 requires they are treated as live.

Regards,
Lyle