Feeder cable nightmare

R

Relisys190

Member
Location
USA
Occupation
Building Operator
This was a message I sent to the manufacturer of Stabiloy ALCAN cable. Backstory, hurricane helene hit our commercial office building in Oct and we suffered an event within our main switch gear cabinet. We now know a phase to phase event occurred and the blast sent salt water up into the cabinet from the conduit under ground. Two conductors were damaged (found during Megger tests )

Insurance did not see the need to replace the gear , only test the 3000 amp breaker and re-install. Only replaced feeders that were damaged .. I need help here….

I operate a 12 story commercial property that was subjected to high levels of storm surge and water entered conduits of our tap box at ground level. There are two switch gears servicing this site, a single 3000 amp as well as a 1600 amp service both fed from the tap box adjacent to our utility transformer . All conductors are 750 MCM XHHW (Please see photo of 4 conductors that we replaced with size and name (stabiloy). There are 9 parallel runs to the 3000amp and 5 parallel runs to the 1600 amp.

We were instructed by an insurance inspector to replace only the conductors in one conduit that had a phase to phase event during the storm.

The rest of the existing conductors where Meggar tested following the storm, tested good and remained in place untouched albeit sitting in salt water filled conduits all of this time. We have been on generator power and I am curious of what the salt water has done over the last 6 months to the existing conductors insulation . The property has been on generator power during this time due to waiting on repairs. No power has been running through these conductors.

I am aware XHHW is “wet” rated but has the insulation been tested long term under salt water conditions ?
During a recent attempt to repower with utility they are seeing continuity across phases and our electrician believes the insulation may have broken down over time. Another more recent Meggar test may prove this theory .

Please respond ASAP as our contractor wanted to pull new conductors back in January prior but this was not approved by our insurance carrier per the forensics engineer who conducted the study said it was not required to replace them. Any help is appreciated !



Need your thoughts guys ! Thank you,

Markus
 
Thank you for approving. To be clear. We have been on generator power for over 6 months. Running a 1 meg directly to the buildings buss riser and another 450 kv is powering my Transfer switch for emergency lighting , one chiller ( two pumps and cooling tower motors and emergency systems (fire pump and domestic water pump). This is costing us 100k per month in rentals and about 75k a month in fuel. We could have purchased SEVERAL new switch gear assemblies and new conductors at this point. It is just non-sense this far .

Best ! -Markus.
 
I don't know that salt water would damage intact insulation, but certainly could make existing damage worse if any metal was exposed. It's possible that a small knick in a conductor(s) could evolve over time into a full blown short.
 
I was on an under construction project that was damaged by Hurricane Sandy. The wire manufacturer was still willing to honor the warranty but the conduit manufacturer not. I believe it was RMC.
 
The cable manufacture (or someone) should have data on salt water.
Did the "forensic engineer" actually inspect the removed & damaged cable?
Not replacing the whole run complete w/cleaning and checking the pipe was a very, very bad idea... ddare i say.
How long was the one run?
There is zero garauntee the run is fixed, imo.
 
rambojoe said:
The cable manufacture (or someone) should have data on salt water.
Did the "forensic engineer" actually inspect the removed & damaged cable?
Not replacing the whole run complete w/cleaning and checking the pipe was a very, very bad idea... ddare i say.
How long was the one run?
There is zero garauntee the run is fixed, imo.
Click to expand...
We had a contractor replace 4 conductors in the conduit that suffered the anomaly back in Oct. The forensic engineer only initially approved the two damaged conductors to be replaced but the contractor argued how impossible it would be to replace only 2 out of the 4 within that run.

The distance is approx 150 feet from tap box to switch gear room. The phase to phase event that occured in the pipe was strong enough to send salt water up into the 3000 amp gear enclosure. The fact that they said it did not need to be replaced is absurd to me. We did have the 3000 sent out for testing and it surprisingly passed inspection. They would not approve a full replacement of the gear nor the other un-effected conductors 8 parallel runs to the 3000 and 5 parallel runs to the 1600 all fed from the tap box.

-M
 
Insurance finally approved replacement of ALL feeder cables. The contractor has pulled out the 52 cables. Each around 115 feet total. They reamed each conduit and used high pressure to blow the remaining salt water out from hurricane Helene . It has been really something… but we are getting close to going back to utility power. Hopefully as early as this Saturday.

-M
 
We passed inspection of all 52 feeders. The vendor completed and we energized with TECO this passed Saturday the 17th. I am
Having issues on the 1600 amp side. I posted a new thread for this. The fun never ends !

-M
 
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