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Submitted By -SPIKE YOUR CABLES REMOTELY
I had a job to dig up and splice new cable onto existing cable. We were to install a dead front switch, replacing the live front. The cables were exposed just behind the live front switch. I had previously switched out these three runs of #2 U.G. cable. I tested the cable as dead then grounded the same cable. With a hot cutter, I cut the #2 pot head connections from the bottom of the live front switch. I then tested and grounded the other ends of the three cables, tagged them and took a clearance on all three. I then hooked up the "Pulse Indicator" at the switch end. I got a good pulse indication on A phase. I moved the "Pulse Indicator" to the other two phases and received a good pulse on B and C phases. The first phase I spiked was A phase. As the spike was being performed, I heard a loud pop. I had just spiked a hot conductor and blew a 100 amp fuse down the line. The "Pulse Indicator" indicated the hot cable as a dead one. A bleed over had occurred. Everyone on my crew was so sure the cables were identified as the dead cables. I still wanted to spike the cables remotely. Thank God I had.
Always remotely spike your cable. When you are in a vault, do it remotely out of the hole. Spike all three cables, even if they exit the same conduit. By doing so you will never fall into the deadly trap of hand cutting up close the "For sure dead cables."