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Submitted By -Drilling A Hole In A Vault
To rack a new 138 kV cable in manholes in Los Angeles we drilled 1/4" holes in the wall and put small bolts temp to hold the pipes used to rack our new cable. We had done this for 17 manholes. On the 18th manhold we hit cable in the wall. The cable was only 1" inside the wall. The cable that was hit was 138kV oil filled cable. The vault wall was poured in place in 1942. The cement was suppose to be 3-4" thick. But back then there is no telling how much cement was used. We drilled 3/8" into the cable and found it due to the arching noise. The cable was de energized inspected and finally replaced under a clearance. This is as close to death as I ever want to be.