I'm not sure how they think they can justify a "leaky" wire. You hired them to pull in new XHHW and when tested, it was damaged. Bad pipe, bad technique, bad wire(?), really doesn't matter. It's ain't what you ordered. ("If I'd wanted a bare neutral, I'd have ordered a bare neutral.")
Thank you -- that's exactly what I've been arguing all this time!
Of course there is much more to this story -- all of it bad. The old aluminum main feeders that brought power into our facility were not the only wires damaged back in 2012. The contractor also damaged a number of the new copper wires he installed for taking our solar power out to the grid.
After half our aluminum main feeders shorted two months ago, we decided that we were going to have all the project's AC feeders and branch circuit conductors (BCC's) megger tested by an independent testing company. Testing of the remaining aluminum main feeders required interrupting power to our facility -- and our commercial tenants. So to minimize disruption, we planned the testing to be done on the same day (Saturday) that the contractor was scheduled to pull out the one conduit of shorted main feeders. This meant we also needed to de-energize and unlug all the solar feeders and BCC's for testing on the same day.
One thing I insisted upon was performing the insulation resistance tests with the wire wetted (i.e., filling the buried PVC conduits with water), because megger testing the wire will not reveal any damage to the insulation if the exposed inner conductor is dry and there's no electrical path to ground. The contractor fought back on this and tried to claim that flooding the conduits would damage something (despite the fact that he knew many of the in-ground conduits he installed were already completely flooded end-to-end from accumulated rain/ground water). To counter his claims, I contacted the wire manufacturer and their standards/specifications engineer confirmed that they factory-test their wire while it is submerged in water. So we flat-out told the contractor in advance that we would be flooding the conduits for testing. But even on the day of the testing, the contractor was yelling at me and trying to stop me from filling the conduits with water.
Anyway, the challenge on our side was to manage and sequence all the various tasks that were to occur that day. We wanted to flood all the conduits, but ten of those conduits (five in one direction, five in the other) opened into the large in-ground pull box where the contractor's employees would be extracting the shorted aluminum feeders. We decided we would wait until after their job was completed before flooding those conduits so not to interfere with their wire removal operation. The problem was, the contractor only brought two men to do the job of pulling out the 360 linear feet of (8) 500 MCM aluminum wires. And the first 200 foot section went very slooooooooowly; in part because of the geometry of the pull, and in part because one of the damaged aluminum wires had internally corroded and swollen to the size of a salami inside the conduit. As a result, the contractor's two employees didn't complete the wire removal until around 9PM at night, long after the man from the independent testing company had left. So the (18) 350 MCM copper solar feeders that passed through that pull-box were meggered, but they were not tested with their conduits flooded. Out of those (18) feeders, three tested bad: two had insulation resistance values so low (9.8K & 2.2M) they had to be taken out-of-service, and one was marginal (50M) but still temporarily serviceable. There were a few other wires that were in the 0.8G to 1.2G range; the rest were 4G or above.
That first set of testing was on 19 April. Which now brings us to last Friday (30 May). In addition to pulling in the eight new 400 MCM copper main feeders, the contractor and his sub were to also remove & replace the three sections of damaged solar feeders (the damaged solar feeders were cut in the pull-box: two sections were bad between the box and the switch gear, and one section was bad between the box and our electrical room). Note that the contractor was not directly involved in the new wire pulls; these were being performed by the sub-contractor. The primary contractor -- and the one electrician he brought with him -- were only unlugging/lugging the wires and making-up the splices.
Again, we hired the independent testing company to come in the afternoon to perform commissioning testing on all the replaced wires, plus we opted to re-test all 18 solar feeders so that they could be tested wet this time. Once again, the contractor objected to the testing and objected to the flooding of the conduits. In fact, he directed his electrician to start lugging some of the newly-pulled wires in the morning before any IR tests had been performed. I had to put a stop to that. Since the contractor and his electrician were not doing anything while the main facility feeders were being pulled, we asked him to unlug the remaining solar feeders at both ends so they'd be ready for when the testing company arrived. Instead, he sat in his truck sulking like a petulant child, so I had to unlug all the feeders myself.
By around 4PM, all wire pulling had been completed and the primary contractor had spliced all the wires, so I could finally proceed with prepping the remaining eight conduits for testing. First, I had to pack the conduit ends in the pull-box with duct seal so the water would be contained within the conduits. Again the contractor complained, claiming it was too late in the day and that the sub-contractor wanted to wrap-up and leave; he wanted to have the wires tested dry. It's a good thing I stood my ground. In addition to the new main feeder wire that tested bad (the subject of my first post), we identified three more defective solar feeders. These were solar feeders that had previously been deemed "good" during the dry IR testing performed a month ago. But with the wet tests, these three wires now measured at 50K, 295K, and 600M Ohms.
The contractor knows that he's going to have to replace the two wires that measure below 1M Ohm. But he claims that the third wire is acceptable because it's over 100M Ohms -- a number that I consider to be rather arbitrary and relevant only for maintenance "Go/No-go" testing, not for new equipment commissioning.** All the other wires exceeded the measuring capacity of the testing meter: >4G Ohms.
In my opinion, NEC 110.7 still applies for this 600M Ohm wire. What say you?
And that's not the end of this saga. Stay tuned for my next thread where I discuss the creative way he "repaired" one of our inverter's damaged BCC's...
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**(Technically, our solar installation is no longer "new" as it was put in service 18 months ago. But since the contractor never performed any testing, these current measurements are the closest we have to commission tests.)
